Abstracts of Papers - Harvard Forest - Harvard University

Abstracts of Papers 

Reviewed work(s): 

Source: American Journal of Botany, Vol. 70, No. 5, Part 2: Program with Abstracts of 

Papers to be Presented at the Joint Meetings of the Botanical Society of America and the 

Canadian Botanical Association with Other Affiliated Societies at the University of North 

Dakota Grand Forks, North Dakota 7-11 August 1983 (May - Jun., 1983), pp. 1-139 

Published by: Botanical Society of America 

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Journal of Botany.

Symposium: Assessing Air Quality with 

Lichens and Bryophytes-Part I 

BRYOLOGICAL AND LICHENOLOGICAL SECTION 

INTRODUCTION - Parts I and II 

This symposium will address various methods of 

using lichens and bryophytes in air quality monitoring. 

Papers will include the topics of floristic 

analysis, mapping of sensitive species, statistical 

analysis of quantitative data, correlating 

fumigation studies with physiological effects and 

with field studies, trace element analysis, species 

variability with respect to air pollution and the 

ecological importance of lichens and bryophytes. 

These papers will summarize techniques presently 

in use and evaluate their reliability and usefulness 

in assessing air pollution damage. 

Organized by Clifford Wetmore, University of Minnesota, 

St. Paul, MN and James Bennett, National 

Park Service, Denver, CO. 

BENNETT, JAMES P. National Park Service, Air 

Quality Division, Box 25287, Denver, CO 80225. 

- The air pollution importance of non-vascular 

plants to the National Park Service. 

The National Park Service (NPS) has a mandate to 

protect the biological resources of the national 

parks from the effects of air pollution. Under 

Clean Air Act regulations, the NPS has authority 

to determine whether or not higher than ambient 

S02 concentrations will cause adverse impacts on 

lichens and mosses in the parks. The NPS consid- 

ers non-vascular plants as integral components 

of natural ecosystems because of their ecological 

importance as colonizers, nitrogen-fixers, food 

sources and soil stabilizers. Their position at 

the base of many food chains makes their role of 

primary importance. 

Lichen sensitivity to S02 and heavy metals 

is well known. Several national parks are cur- 

rently experiencing elevated S02 concentrations, 

some high enough to cause effects on lichens and 

mosses. The NPS has initiated six projects on 

lichens and mosses and air pollution, including 

floristic studies, sulfur baseline sampling, 

heavy metal sampling, and ecological community 

analyses. These studies will enable NPS to de- 

termine future adverse impacts on non-vascular 

plants in the parks. 

NASH III, THOMAS H. Department of Botany 

& Microbiology, Arizona State University, 

Tempe, AZ 85287 - Correlating fumigation 

studies with field effects. 

Differential tolerance of different lichens 

to the environment of cities and isolated 

pollution sources is well established. It 

is frequently assumed that these patterns 

reflect differential sensitivity to sulfur 

dioxide and/or other air pollutants. This 

assumption may be false or only partially 

true because lichens may well respond to 

alteration of other environmental factors. 

Fumigation studies with controlled levels 

of air pollutants provides a means for ex- 

perimentally establishing whether lichens 

are in fact sensitive to air pollutants. 

It is important that both realistic exposure 

durations and realistic pollutant concentra- 

tion levels be employed. Furthermore, ex- 

posure conditions must be chosen to reflect 

conditions characteristic of the environment 

where th lichens occur naturally. The fumi- 

gation literature is critically examined 

with respect to these caveats and examples 

are given where the hypothesis that lichens 

are sensitive to air pollutants is both 

supported and not supported. 

NIEBOER, EVERT* and KEN A. KERSHAW, Departments of 

Biochemistry and Biology, McMaster University, 

Hamilton, Ontario, Canada, L8N 3Z5. 

- Ecological Implications of Laboratory Toxicity 

and Related Photosynthetic Studies. 

It will be demonstrated that a large proportion of 

the elemental content of lichens is the result of 

particulate trapping within the interstitial spaces 

of the thallus. A strong dependence on surface 

morphology can be illustrated for this phenomenon. 

Such accumulation may be expected to be relatively 

innocuous. Recent studies will be reviewed that 

show that the largely passive extracellular uptake 

of metal ions can be either protective or deleteri- 

ous, depending on the chemical reactivity of the 

metal cation. Dissection studies are reported that 

indicate that metal-ion binding occurs to both the 

algal zone and fungal medulla, and that the uptake 

capacities of these zones, as well as the total 

uptake, are strongly lichen species dependent. Work 

with the uranyl ion further illustrates the import- 

ance of chemical speciation. And finally, toxic 

effects of ion absorption and SO2 exposure are shown 

to be ameliorated by the mineral status of the 

thallus (high Ca2+, Mg2+, K+ contents), by uptake 

inhibition (phosphate competing with arsenate; metal 

-ion rivalry), and high photosynthetic capacities. 

In this context, laboratory studies that simulate 

seasonal variations in photosynthetic capacities are 

summarized. In addition to species susceptibility, 

these observations imply a substrate and seasonal 

dependence of the toxicity to lichens of environmen- 

tal pollutants. Inferences for the use of lichens 

as monitors of environmental pollution will be 

pointed out. 

PUCKETT, KEITH.* J. & SEDIGHEH SANG. 

Atmospheric Environment Service, 

Environment Canada, 4905 Dufferin St., 

Downsview, Ontario, M3H 5T4. 

-Trace element mapping with lichens and 

bryophytes. 

Since lichens and bryophytes are known to 

obtain and accumulate metal pollutants as 

well as their required nutrients from the 

atmosphere (either from rainfall or by 

impaction and sedimentation of airborne 

dust), they have been employed as 

biological indicators of trace element 

fallout in a great number of studies. In 

this paper enhanced levels of elements in 

lichens and mosses were reviewed and the 

usefulness of these plants for monitoring 

and mapping the concentrations of 

1

2 Bryological and Lichenological Section 

atmospheric pollutants around industrial 

plants is discussed. The review of the 

literature suggests that lichens and 

bryophytes either growing naturally or 

transplanted near a pollution source absorb 

and accumulate high concentrations of 

elements (e.g. Cd, Co, Cr, Cu, F, Fe, Hg, 

Ni, Pb, S, V, Zn) in their tissues. This 

accumulation appears to be related to both 

the distance from the source and prevailing 

wind conditions. In conclusion, using 

lichens and mosses as biological indicators 

of air pollution can prove to be a very 

reliable, inexpensive and practical method 

for monitoring the deposition of trace 

elements from the atmosphere. 

SHOWMAN, RAY E. Environmental Engineering 

Division, AEP Service Corporation, P.O. Box 487, 

Canton, OH 44701. - Mapping air quality with 

lichens. 

North American lichen - air quality mapping literature 

is reviewed and discussed. Lichen studies 

fall into two general categories, distribution and 

IAP mapping. Distribution mapping is best suited 

for areas where there is a significant air quality 

impact. In areas experiencing only slight effects 

a simplified IAP or other quantitative method is 

recommended. Care must be taken in interpreting 

lichen maps. In most areas a quantitative correlation 

between lichen success and long-term average 

air quality data is not possible. Never the less, 

lichen mapping is a valuable tool for obtaining a 

simple, inexpensive measure of the biological 

impact of air pollution. 

WETMORE, CLIFFORD M. Botany Department, 

University of Minnesota, St. Paul, Minn. 55108. 

-Lichen floristics and air pollution. 

Lichens are very sensitive to air pollution and many species 

are killed by low levels of pollutants. Not all species 

are equally sensitive and some are quite tolerant. By 

studying the lichen flora of a particular area one can 

draw certain inferences about the pollutant levels based 

on presence or absence of different lichens with different 

sensitivities. In order to use this survey method one must 

know the lethal levels of the pollutants for as many species 

as possible and one must have historical or 

phytogeographical and ecological information about the 

natural lichen flora. In some areas historical records are 

available but in others comparisons must be made with 

nearby clean areas. The distribution of the sensitive 

species within the study area can also give information 

about pollution levels. Sub-lethal levels of pollutants can 

be determined by analysis of lichens for levels of chemical 

elements. Ihis method of air pollution study is less precise 

than by using IAP or other quantitative methods but is 

useful when many or large areas need to be rapidly 

surveyed for air pollution. Ihe areas showing some 

reduction in the lichen flora can then be studied in more 

detail by other more sensitive methods. 

WILL-WOLF, SUSAN. Department of Botany, 

University of Wisconsin, Madison, WI 53706. 

- Statistical analysis of air pollution 

indicators . 

A survey of published field studies in which air 

pol1lut ion ef fect s were as ses sed us ing l ichens and/ or 

bryophytes, shows that the most common monitoring 

approaches in North America since 1973 have been 

1) use of lichen species numbers, diversity, or IAP 

values, and 2) measuring levels of various elements 

accumulated in lichens and mosses. Both approaches 

were generally used to delineate impact zones 

around moderate to heavy-dose point sources or urban 

areas. Whenever possible, field studies should be 

designed to allow data analysis using appropriate 

parametric statistics, such as ANOVA, multiple 

regression, or partial correlation. Non-parametric 

statistics are required whenever percentage data, 

qualitative evaluations, or indices using ratios are 

compared. Chi-square tests are appropriate for 

comparing frequency distributions of all kinds, such 

as community composition data or cover classes. 

Complex multivariate analysis techniques such as 

ordination, classification, or discriminant analysis 

are best used to provide supporting information 

rather than directly to document air pollution 

impact. Useful sample designs and analysis 

approaches are given for some monitoring situations 

not extensively treated in the literature: 1) 

effects of low-dose point source emissions, 2) 

effects of interactions between pollutants in the 

field, and 3) effects of regional air pollution. 

Symposium: Assessing Air Quality with 

Lichens and Bryophytes -Part II 

SLACK, NANCY, G. Department of Biology, Russell 

Sage College, Troy, New York, 12180. 

-Ecological importance of lichens and bryophytes: 

what happens if they disappear? 

Quite apart from their importance in assessing air 

quality, the subject of this Symposium, lichens and 

bryophytes have recently been shown to play a wide 

variety of roles in diverse ecosystems. In addition 

to their traditional role as "pioneers" in soil for- 

mation, soil retention, and colonization of difficult 

habitats not open to other groups, recent research 

has elucidated their important roles in nitrogen 

fixation, nutrient cycling, and in the food chain of 

mammals. Productivity studies have shown the impor- 

tance of bryophytes as primary producers particularly 

in arctic and mire ecosystems, with values up to 

800 g m2 year1 reported. High biomass values for 

both bryophyte and lichen epiphytes have been re- 

ported in old growth Pseudotsuga forests in Oregon. 

Cyanophilic lichens, particularly Lobaria oregana, 

have an important role in nitrogen fixation in these 

forests. The genus Lobaria is highly susceptible to 

air pollution;Lobaria pulmonaria, a nitrogen-fixer in 

deciduous forest, has disappeared from many of its 

former locations in Britain. Nitrogen fixation by 

both extra- and intracellular blue-greens association 

with Sphagnum species has been reported in both 

temperate mires and Sphagnum communities in conif- 

erous forest in Sweden, and in mires in Arctic 

Alaska, Swedish Lapland and Finland. Nutrient 

cycling in both bryophytes and lichens and the rela- 

tionship of these nutrient cycles to the utilization 

of these plants by caribou has been studied in Nor- 

thern Canada and Arctic Alaska. Whereas lichens are 

the primary winter food of caribou and reindeer, 

mosses are also important in the high Arctic, e.g.for 

reindeer in the Svalbard Archipeligo. Mosses and/or 

lichens are also important in the food chains of 

such diverse organisms as mites, lemmings, and people. 

WIRTH, VOLKMAR. Staatliches Museum fir 

Naturkunde Stuttgart, Arsenalplatz 3, D- 

7140 Ludwigsburg, Federal Republic of Ger- 

many. - Phytosociological approaches to 

air pollution monitoring with lichens. 

Phytosociology is an approach to the study of

plant communities that has been extensively 

employed throughout Europe. Basic principles 

by which different hierarchial groups of 

lichens are distinguished, are discussed and 

examples are given. Epiphytic lichen associ- 

ations have clearly been modified over the 

past two hundred years. This can be docu- 

mented by herbarium records as well as carto- 

graphic studies. Even the formerly widely 

distributed Xanthorion parietinae alliance, 

that normally prospers in areas adjacent hu- 

man settlements, has declined markedly. Many 

of the patterns in lichen community modifica- 

tions can be correlated with measured SO2 

levels. A number of lichen species have ap- 

parently disappeared entirely from the Feder- 

al Republic of Germany and about 50% of the 

lichen flora is considered endangered. 

Poster Session 

BASILE, DOMINICK V., MARGARET R. BASILE 

and ROSS E. KONING. Lehman College of 

CUNY, Bronx, N.Y. 10468 and Rutgers Univ. 

Piscataway, N.J. 08854. 

- Ethylene production and its possible 

role in regulating leaf and branch devel- 

opment in Plagiochila arctica, a leafy 

liverwort. 

Ethylene production by gametophytes of 

Plagiochila arctica Bryhn & Kaal. in axenic 

culture was determined by means of gas- 

liquid chromatography (GLC). Exogenous 

indole acetic acid (IAA) at approx. 6x 

10-5M markedly stimulated ethylene syn- 

thesis while aminoethoxyvinyl glycine (AVG) 

at approx. 10-5M significantly suppressed 

it. In these respects ethylene production 

and its regulation are the same in P. 

arctica as in representatives of the 

flowering plants (Magnoliophyta). Although 

these results may have been inferred, they 

were hitherto unsubstantiated. Furthermore, 

these data in conjunction with those ob- 

tained in previously completed experiments 

lend support to an hypothesis that auxin- 

induced ethylene synthesis plays an impor- 

tant role in regulating leaf and branch 

development in leafy liverworts, particu- 

larly those originating from ventral mero- 

phytes. 

JANSSENS, JAN A. & PAUL H. GLASER. Limnological 

Research Center, University of Minnesota, Minneapolis, 

MN 55455. 

- Fossil bryophytes and peat stratigraphy in the 

development of Red Lake Peatland, northern Minnesota. 

Ten peat cores, reaching down to the mineral sediment, 

taken along a transect 7-km long in the center 

of the vast Red Lake Peatland in northern Minnesota, 

were analyzed to reconstruct the development of a 

mire complex consisting of forested ovoid bog islands 

separated by internal water tracks marked by patterned 

fens. The reconstruction of past bog, poor-fen, 

and rich-fen communities is based primarily on the 

quantitative analysis of fossil bryophyte assemblag- 

Bryological and Lichenological Section 3 

es; concentration by weight and volume, accumulation 

rates, and percentages of identified taxa were cal- 

culated. The sharply defined bryophyte zones were 

stratigraphically correlated among cores by radio- 

carbon dates, the regional pollen zonation, and bu- 

ried wood layers. Peat-accumulation rates, calculated 

from radiocarbon dates, were correlated with measure- 

ments of bulk density, humification, and peat ontoge- 

ny as based on the local paleoenvironmental recon- 

struction. The peat stratigraphy indicates that bog 

vegetation originated about 5000 years ago at the 

watershed crest and then extended downslope, growing 

over rich-fen peat in the process. Cores from the 

internal water tracks contain a striking sequence in 

fossil assemblages, changing from a basal rich-fen 

zone to a bog or oligotrophic poor-fen zone and then 

reverting back to a rich-fen zone towards the top. 

This stratigraphy supports an earlier hypothesis, 

based on the study of present-day landforms, that the 

internal water tracks originated recently within a 

continuous complex of forested raised bogs, with 

poor-fen lawn flanks. Conversion of the bog into 

ovoid islands resulted in the complex landscape. 

Contributed Papers 

Allen, Bruce H. Department of Biological 

Sciences, University of Cincinnati, 

Cincinnati, Oh 45221.- The protonema of 

Drummondia prorepens. 

Spore germination in D. prorepens is 

precocious and endosporic. On sowing of 

these endosporic protonemata dimorphic 

protonemal filaments arise: those with long 

rhomboidal cells having end walls oblique 

to the long axis, and those with cells more 

or less square the end walls at right angles 

to the long axia. By means of anticlinal 

and periclinal divisions in the latter a 

massive three-dimensional protonema is 

formed.. Periclinal divisions in the former 

results in their elongation into the medium. 

Occasional divisions at right angles to the 

oblique end walls of the long celled fila- 

ments form cells that give rise to three- 

dimensional cell masses. Leafy gametophytes 

originate on the primary cell mass within 

20 days, and on the secondary cell masses 

within 59 days. This sporeling type is 

similar to that reported for some species 

of Ptychomitrium, Hedia and Drummondia. 

The sa.lient feature of this type is the 

ability to form, free from the constraint 

of the spore wall, a primary three- dimen- 

sional protonema. Rapid development of 

leafy gametophytes is considered the 

principal advantage of this type of spore- 

ling development: minimizing the risk of 

dessication and of being washed onto an 

unsuitable substrate. 

ANDERSON, DAVID C., LARRY 

ST. CLAIR 360 Wakara Way 

Salt Lake City, Utah 84108 

-Selection of useful parameters in assessing lichens 

as biological monitors of air pollution. 

The use of lichens as biological monitors of air qual- 

ity although in its infancy affords an "early warning"


system to potential impacts of air pollution on bio- 

logical activity. Two studies recently conducted in 

southeastern Wyoming and in eastern Utah evaluated the 

use of such a system. At permanent plots established 

at incremental distances from pollution sources the 

lichen community was characterized and the membrane 

permeability, a measurement of cell damage, of select- 

ed lichen speices was determined. The purpose of the 

studies was to identify paramenters most accurately 

replicated and to characterize the existing lichen 

community. In southeastern Wyoming, membrane- leakage 

values for Parmelia chlorochroa, a terricolous lichen, 

was significantly higher at the Dave Johnston plant, 

a plant on line since 1958, in comparison to the 

Laramie River plant, in use since 1980. Data from the 

Dave Johnston plant show significantly higher membrane 

leakage values, higher lichen selenium content and 

lower weight per individual at sites nearest the pol- 

lution source. On oil shale lands in eastern Utah, 

the results of a similar study showed that the percent- 

age of total lichen cover, the number of species/quad- 

rat and the sulfur content of the lichen thallus were 

the least variable parameters measured. The percent- 

age of total cryptogamic cover, the number of lichen 

species per unit area, membrane leakage and to some 

extent, elemental analyses of lichen tissue were para- 

meters most replicatable and would, therefore, serve 

as good indicators of lichen community conditions. 

BENNETT, JAMES P. National Park Service, Air 

Quality Division, Box 25287, Denver, CO 80225. 

- Air pollution studies on lichens in Denver, 

Colorado. 

Denver, Colorado is not known for having very 

high air quality. The notorious "brown cloud" 

is easily observed by many visitors. Using the 

Pollutant Standards Index (PSI) for 1978 to 1980, 

Denver ranked fourth in the nation for having 

polluted air. The composition of the pollution 

is the subject of a continuing controversy, but 

the presence of S02 can not be ruled out. Know- 

ing that lichens are extremely sensitive to low 

levels of S02, a study was initiated to map li- 

chen frequency on tree trunks. The presence/ 

absence of lichens are noted on a minimum of 100 

trees at least 30 cm diameter in size in parks, 

cemeteries, school yards or other locations con- 

taining sufficient number of trees. To date, 

over 2500 trees have been sampled. Only two 

species of corticolous lichens are encountered in 

Denver, the most common being Xanthoria fallax. 

With over 20 sites sampled so far, a strong rela- 

tionship has been found between the probability 

of encountering a lichen on a tree trunk and lin- 

ear distance from the city center (r = 0.73). 

An objective of the study is to sample a minimum 

of 50 sites systematically located at selected 

distances and compass directions from the city 

center. A model can then be developed relating 

the probability of lichens occuring on tree 

trunks to various geographic parameters. With 

only one S02 monitoring station in Denver it will 

not be possible to relate these effects to air 

quality, but the observed trend would suggest the 

need for more monitoring. 

DALE , MARK R. T. Botany Dept ., University 

of Alberta, Edmonton, Alberta . T6G 2E 1 

The geometry of adj oining lichen thalli in 

relation to their growth rates 

Models of the growth rates of lichen thalli 

usually include an initial phase of exponen- 

tial radial growth, followed by a phase of 

linear growth. These models predict that 

the shape of "truce" boundaries between 

adjoining thalli will have characteristic 

changes in curvature at points where growth 

has become linear. Thus a comparison of the 

shapes predicted from these models with 

those observed in boundaries between lichen 

thalli (most easily seen in species like 

those of Rhizocarpon which have distinct 

hypothalline margins) permits an evaluation 

of the models without long term studies. In 

cases where the models prove to be appropri- 

ate, the geometry of the boundaries provides 

estimates of the size at which growth be- 

comes linear. It is possible that once the 

growth curves for several species are known, 

a comparison of inter- and intraspecific 

boundaries will prove useful in evaluating 

the relative rates of linear growth in 

different species. 

DEWEY, RICHARD M. Department of Biology, Texas 

A&M University, College Station, TX 77843 

- Electrophoretic evidence for the recognition of 

Riccia mcallisteri. 

The relationship of the two concepts, Riccia 

dictyospora M.A. Howe, Bull. Torrey Bot. Club 28:163. 

1910., and R. mcallisteri M.A. Howe, The Bryologist 

20:35. 1917., is among the most vexing problems in 

the taxonomy of North American representatives of 

Riccia subgenus Riccia. An inability to discern 

reliable critical morphological differences between 

the two species has prompted some workers to view R. 

mcallisteri as a taxonomic synonym. Plants repre- 

senting R. dictyospora, sensu lato, have been 

collected in several central Texas localities, 

including the type locality of R. mcallisteri. When 

surveyed with starch-gel electrophoresis, plants 

assignable by morphology to either R. dictyospora or 

R. mcallisteri have exhibited distinctive phenotypes 

for isozymes of malate dehydrogenase, acid phospha- 

tase, peroxidase and aspartate amino transf erase. 

This preliminary electrophoretic evidence supports 

the recognition of R. dictyospora and R. mcallisteri 

as distinct species. 

ELIX, JOHN A. Department of Chemistry, Australian 

National University, P.O. Box 4, Canberra 2600, 

Australia. 

- Lichens in Papua New Guinea 

The lichen flora of Papua New Guinea is still poorly 

known, but even after a cursory investigation the 

contrast between the flora of the tropical lowland 

forests and higher altitude montane forests are 

particularly striking. Corticolous substrates are 

most important in both environments, but crustose 

growth forms growing on tree trunks and branches 

dominate in the coastal forests where lichen cover is 

high but biomass low. Genera such as Graphis, 

Arthonia and Anthracothecium are particularly abundant 

In the lower montane Castanopsis and Araucaria forests 

pantropical macrolichen genera such as Parmotrema, 

Usnea and Leptogium are prominent, while in the higher 

montane Nothofagus forests the genera 

Pseudocyphellaria, Sticta, Lobaria and Anzia are 

preponderant. Interestingly the former two genera 

and common associates (Menegazzia, Psoroma) are 

presumably of Gondwanaland origin and also prominent 

in the Nothof agus f orests of Tasmania, New Zealand 

and Chile, while Lobaria and Anzia appear of Asiatic 

origin. This dichotomous origin appears to be 

reflected in much of PNG's lichen flora.

GLIME, JANICE M. Department of Biological Sciences, 

Michigan Technological University, Houghton, MI 

49931. - A photographic study of spore and 

protonema development in Fontinalis squamosa. 

Electron microscopy was used to demonstrate 

development and arrangement of spores within the 

capsule. Spore viability, germination, and protonema 

development are illustrated by light and fluorescence 

microscopy. The presence of two spore sizes is 

clearly demonstrated and the reduced viability of the 

smaller spores is demonstrated by reduced fluoresence. 

Germination is demonstrated in culture from 5?C-22?C 

and requires light and moisture, but not submersion. 

Protonemata branches arise from 1-3 points on the 

spore, depending upon conditions. Germination and 

development are slow and depend upon the state of 

maturation of the spores at the time of culture. 

Bud development is very slow and the requirements for 

budding are unclear. 

GOWIAN, SHARON P. Botany Division, National Museum 

of Natural Sciences, National Museums of Canada, 

Ottawa, Ontario KIA OM8, Canada - A study of roof- 

dwelling lichens and the possible effects of a 

nearby phosphorus plant. 

Concern has been expressed by the inhabitants of Long 

Harbour, Newfoundland, about abundance in their town 

of roof-dwelling lichens, and the possible relation- 

ship of their growth to phosphate- and fluoride-con- 

taining substances escaping from a nearby phosphorus 

plant. In response to this concern, an ecological 

study was undertaken to compare the roof-dwelling 

lichen community in Long Harbour with that in nearby 

towns lacking any significant sources of atmospheric 

contamination. Results show a concentration of 

"enrichment species", especially Xanthoria polycarpa 

and Physcia tenella in Long Harbour, whereas species 

characteristic of acid bark and rocks, especially 

Hypogymnia physodes and H. tubulosa predominate in a 

nearby town. Coverages and effect of lichens on 

their substrate in the two towns are comparable. It 

is hypothesized that the abundance of enrichment 

species in Long Harbour is at least partially a re- 

sponse to high concentrations of air-borne dust rich 

in phosphates. 

GRAHAM, LINDA E. Department of Botany, Univer- 

sity of Wisconsin, Madison, WI 53706. 

- Coleochaete: Advanced green alga or primitive 

embryophyte? 

Ultrastructural studies of reproductive development 

in Coleochaete have revealed a number of features 

that do not occur elsewhere in the green algae, but 

which are characteristic of embryophytes. Filament- 

ous species of Coleochaete produce unicellular 

antheridia as do other green algae, but the 

parenchymatous species may produce internal, multi- 

cellular antheridia that resemble early developmental 

stages of land plant gametangia. Following 

fertilization, the zygote of Coleochaete is retained 

on the haploid plant, and apparently induces the 

formation of a layer of covering cells that may 

produce localized wall ingrowths. These cells 

resemble gametophytic placental transfer cells of 

embryophytes in location, time of development, and 

ultrastructure. Upon germination, the zygote 

develops into a multichambered, spore-producing 

structure that is not observed elsewhere among 

green algae, but which resembles spore mother cells 

of embryophytes in some important features. 

Finally, Coleochaete produces more spores per 


fertilization elSent than other freshwater, or 

haploid, haplobiontic green algae. This last 

feature is probably related to retention of the 

zygote, zygote enlargement and storage of photo- 

synthate, and putative nutrient interactions between 

haploid aind diploid phases of the life cycle. These 

features may thus have been preadaptations of major 

importance during the transition of plants to land 

and the origin of embryophytes from charophycean 

algae. 

HOARE, JANET K. Room 429 Hensill Hall, 

San Francisco State Univ.,San Francisco,CA94132 

- Lichen succession 

ian lava flows. 

and diversity on dated Hawai- 

Lichens were collected on lavas of thirty-two ages 

on the island of Hawaii to determine lichen succession 

and diversity on a series of lava substrates of 

known ages. One hundred eighty-six collections 'were 

made at sixty sites representing nine geographic 

locations. Stereocaulon is the most prevalent genus 

and, with Lepraxia, becomes established in less than 

ten years, fo'llowed by foliose genera (largely Parmelias), 

and Cladonias. Crustose genera appear on 

lavas at least thirty years old, but are uncommon 

on lavas younger than a few hundred years. The greatest 

lichen diversity was found on old lavas at sea 

level in the south-east portion of the island where 

rainfall is moderate. The most profuse growth (Stereocaulon) 

appears on lavas one hundred and fifty 

years old in the central saddle area where rainfall 

is heavy. 

LAWREY, JAMES D. Department of Biology, George 

Mason University, Fairfax, VA 22030. 

- Lichen herbivore 

ance? 

behavior: preference or avoid- 

Field data collected in a saxicolous lichen community 

in Shenandoah National Park showed that the lichen 

herbivore Pallifera varia prefers certain lichen 

species to others. Two hypotheses were developed to 

explain this preference. The avoidance hypothesis, 

that preference by slugs actually results from the 

rejection of unpalatable species, was tested by offering 

slugs choices of filter paper disks impregnated 

with secondary products of the avoided and preferred 

species. The preference hypothesis, that slugs select 

lichens of highest quality, was tested by measuring 

the ooncentration of essential elements in 

lichens eliciting high and low preference by slugs. 

Lichens with the highest element contents were assumed 

to be of highest quality to herbivores. Results 

showed that the preferred lichens had significantly 

lower concentrations of N, P, and Ca, and that 

avoided lichens produced secondary compounds that inhibited 

P. varia grazing activity. These results 

suggested that lichens with high concentrations of 

essential elements are most likely to produce defense 

compounds, an observation supporting some explanations 

for chemical defense patterns in vascular plants. 

Mankiewicz, Paul S. Harding Laboratory, 

New York Botanical Garden, Bronx, New 

York, 10458 

-Water conduction by external capillary 

spaces and the shape of bryophyte 

colonies. 

While the major kinds of bryophyte colonies 

have been well described in the literature, 

there have been no empirical studies of the 

spatial arrangement of plant axes in cushions,


wefts, tufts,and canopies of bryophytes. In 

the present study, two sets of methods have 

been elaborated: one set of methods permits 

the external capillary spaces within bryo- 

phyte colonies to be visualized by modifi- 

cations of standard parafin embedding methods, 

as well as other novel means using colloidal 

infusions or polymerization; the other set 

of methods permit direct laboratory dr field 

measures to be taken of water flow through 

a bryophyte colony. The results of these 

methods demonstrate that cushions, wefts, 

tufts and canopies are: 1)qualatatively 

distinguishable in terms of the distribution 

of axes and appendages within the colonies; 

and,2) quantatively distinguishable in terms 

of the amount of water that the cross section- 

al area of a given colony type is capable 

of transporting. 

MATTHES-SEARS, UTA and THOMAS H. NASH III. 

Department of Botany and Microbiology, Arizona 

State University, Tempe, AZ 85287. - Morphological 

and physiological variations of Ramalina menziesii 

along a coast-inland gradient. 

The corticolous lichen Ramalina menziesii Tayl. shows 

marked morphological variation along a coast-inland 

gradient in western California. Photosynthetic 

patterns throughout the year were studied at a 

coastal and an inland site and found to differ markedly 

as a result of the oceanic influence which 

modifies the moisture aspect of the climate. Both 

populations became activated by rainfall and dew 

during the rainy season; these winter photosynthetic 

rates were generally higher at the coastal than the 

inland site. During summer, the inland population 

was inactive due to drought, whereas the coastal 

population was regularly activated by coastal fog and 

high atmospheric humidity. Preliminary data show 

that the finer, less reticulate coastal morphotype 

was slightly more efficient in absorbing water vapor 

from the air and consequently exhibited higher 

photosynthetic rates under conditions of high atmospheric 

humidity. This suggests an adaptation of 

the coastal population to utilization of non-precipitation 

sources of moisture. 

MILLER, HARVEY A. Department of Biological 

Sciences, University of Central Florida, 

Orlando, Florida 32816 - Two hepatic genera new 

to Hawaii and Polynesia. 

Among the thousands of unreported collections of 

Pacific island bryophytes assembled by the author, 

many specific novelties have been discovered. Two 

genera found among these collections, Southbya and 

Aphanolejeunea, have not been reported previously 

from Hawaii and Polynesia. Southbya is new to all 

tropical Pacific islands and its presence in Hawaii 

provides additional evidence for a floristic tie to 

temperate Asia. Aphanolejeunea was reported by 

Stephani from Norfolk Island but that questionable 

record until now has been the sole report for the 

tropical Pacific. 

MISHLER, BRENT D .* and STEVEN P . CHURCHILL . Farlow 

Herbarium, Harvard University, Cambridge, MA 02138 

and Division of Biological Sciences, University of 

Kansas, Lawrence, KS 66045. - On the application 

of Hennigian 

bryophytes. 

cladistics to the phylogeny of the 

The empirical concern of bryophyte systematists with 

new methods for studying characters has generated 

important new data bearing on the relationships of 

these plants. It is important also, however, to pay 

explicit attention to the theory behind systematics 

and the study of phylogeny, to the assumptions, justifications, 

and even procedures that have usually 

been left implicit. We argue that the application of 

Hennigian cladistics to bryology can provide a rigorous 

framework for investigating phylogeny, sound concepts 

of monophyly, homology, and relationship, and a 

maximally useful basis for classification. We present 

the results of a study of the cladistic relationships 

of the major groups of bryophytes, with 

respect to the green algae and the tracheophytes. 

While the embryophytes as a whole do seem to form a 

monophyletic group, the bryophytes (sensu lato) are 

paraphyletic. The mosses appear to have shared a 

more recent compmon ancestor with the tracheophytes 

than either has with the liverworts or hornworts. 

The phylogenetic placement of the hornworts is more 

problematical, but on the basis of current information, 

they seem to have shared a more recent common 

ancestor with the moss-tracheophyte lineage, than 

with the liverworts. Hennig's central phylogenetic 

insight, that only shared, derived characters are 

evidence of relationship, can provide a focus for 

further research to test and refine the preliminary 

cladogram presented here. 

MISHLER, BRENT D.* and DANIEL C. SCHEIRER. Farlow 

Herbarium, Harvard University, Cambridge, MA 02138 

and Department of Biology, Northeastern University, 

Boston, MA 02115. - Development of the leaf of 

Tortula obtusissima: systematic and ecological 

implications. 

The development of leaves of field-collected and cul- 

tured plants of Tortula obtusissima (C. Muell.) Mitt. 

has been studied with light microscopy, SEM, and TEM. 

Leaves of young gametophores produced from spores 

show a characteristic juvenile morphology, differing 

from adult leaves in shape, curvature of the leaf 

margin, and the merely apiculate apex. The hollow 

papillae are initially simple, on 3-5 regions of both 

surfaces of the leaf cell, and develop by enlarging 

and bifurcating twice, finally becoming antleroid. 

Leaf ontogeny is of potential phylogenetic importance 

when compared to other species of Tortula with mature 

leaf morphologies similar to the juvenile morphology 

of Tortula obtusissima, and in which the same type of 

papilla is elaborated to a lesser or greater extent. 

Mature leaves of Tortula obtusissima are keeled, with 

recurved margins and a long-excurrent, hyaline, 

serrate awn. The basal leaf cells are hyaline, rect- 

angular, often with both surface walls resorbed and 

standing open wet or dry. The upper leaf cells are 

strongly mamillose, in addition to bearing the char- 

acteristic papillae, and have a cuticle. The leaf 

morphology appears to have several ecological func- 

tions. The perforated basal cells and sheathing leaf 

bases serve for external water transport. The great- 

ly amplified cell membrane in the hollow papillae 

implies transport processes--an external analogy to 

the transfer cells at the foot of moss sporophytes. 

The papillae, which with the mamillose cell walls 

form channels for capillary movement of water over 

the leaf surface, may also serve to facilitate gas 

exchange during active photosynthesis. 

NEUMANN, ALAN J. and DALE M. J. MUELLER*. Department 

of Biology, Texas A&M4 University, College 

Station, TX 77843. -Structure and function of 

the peristome in Leucodon julaceus (Musci).

The sporophyte of Leucodon julaceus (Hedw.) Sull. has 

a peristome consisting of a reduced endostome and an 

exostome of sixteen stout, pale teeth that are orna- 

mented with papillae on the upper two-thirds of the 

teeth. The endostome is composed of cellulosic prim- 

ary cell walls of the inner (IPL) and primary (PPL) 

peristome layers, plus heavy secondary wall thicken- 

ings on the IPL which appear to be of carbohydrate 

and lipid composition. The exostome is composed of 

portions of adjacent periclinal cell walls of the PPL 

and outer (OPL) peristome layers and a common middle 

lamella. The middle lamella is composed of pectin- 

aceous and lipoidal compounds. The adjacent primary 

walls of the PPL and OPL are composed of densely 

packed cellulosic microfibrils. The primary walls 

are highly birefrigent and the main axis of micro- 

fibril orientation is parallel to the longitudinal 

axis of the tooth. Secondary wall thickenings are 

heaviest along the PPL and consist of cellulosic 

microfibrils embedded in a matrix of other carbohy- 

drate and lipoidal compounds. The basal one-third of 

the exostome exhibits the heaviest secondary thicken- 

ings on the inner lamellae. The peristome functions 

in the regulation of spore release and is classified 

as hydrocastique because spore release is favored 

during periods of high humidity). The second- 

ary wall thickenings at the base of the inner 

lamellae of the exostome swell upon hydration, caus- 

ing the teeth to reflex to an erect position, thus 

allowing unhindered release of spores from the urn. 

Upon dehydration, these thickenings of the inner 

lamellae shrink causing the teeth to inflex over the 

mouth of the urn. 

OLAFSEN, ASTRID G. * and THOMAS H. NASH III. 


State University, Tempe AZ 85287. 

- Patterns in carbon and nitrogen fixation in two 

lichens from arctic habitats. 

Peltigera canina and Stereocaulon tomentosum, two disparate 

nitrogen-fixing species, were monitored diurnally 

in situ throughout the summer at Anaktuvuk Pass, 

Alaska. Nitrogen fixation showed greter responses to 

changes in thallus water content (%oven dry weight) 

than did carbon fixation. At thallus water less than 

250% (P. canina) and 160% (S. tomentosum), nitrogen 

fixation declined, almost ceasing at 100%, in contrast 

to carbon fixation, which began dropping rapidly at 

100% for both species. Above 250% and 160%, nitrogen 

fixation increased gradually, peaking at 300% and 200% 

for P. canina and S. tomentosum, respectively. Carbon 

fixation plateaued at water greater than 100% for both 

species, with no decline at high water contents, which 

never exceeded 520% for P. canina nor 350% for S. tomentosum. 

Nitrogen fixation increased with temperature, 

both species having their highest activity (15 nmoles 

C2H4 mg-lhr-l (P. c.) and 4.2 nmoles C 2H4 mg-lhr-l 

(S. t.)) recorded at 19-21? C, while any photosynthetic 

increase with temperature was indistinguisable 

from the light effect. Gross photosynthesis saturated 

at 260-320 ,uE (.28 cal cm 2min 1) for P. canina, and 

100 ,uE higher for S. tomentosum, with nightime fixation 

5-10% of daytime levels; nightime nitrogen fixation 

continued on par with daytime levels, showing no 

increase with increased light. Since 90% of the observed 

light levels and 80% of the observed temperatures 

of physiologically active samples were at or below 

these optima, 

photosynthesis 

both species were light 

and temperature limited 

limited for 

for nitrogen 

fixation through most of the season. 


RUSHING, ANN E.*, ZANE B. CAROTHERS AND JEFFREY G. 

DUCKETT. Department of Botany, University of 

Illinois, Urbana, IL 61801 and School of Biological 

Sciences, Queen Mary College, Mile End Road, London 

El 4NS. U.K. Some aspects of spermatid microanatomy 

in the Jungermanniales. 

A comparative study of the locomotory apparatus and 

cytoskeleton of Cephalozia lunulifolia and Chiloscyphus 

pallescens (Jungermanniales) has revealed numerous 

similarities between these two species and notable 

differences from previously investigated hepatics. 

In both species, the spermatid mother cells undergo 

ovalization prior to the final mitotic division, and 

the multilayered structure (MLS) shows the typical 

4-layered morphology. In Cephalozia, the anterior 

portion of the lamellar strip (LS) is wider on both 

sides than the narrow anterior portion of the spline 

but is equal in width to the sDline at its maximum. 

Similar lateral extensions of the LS were not observed 

in Chiloscyphus. At its widest, the spline 

of Cephalozia comprises 17 microtubles while that of 

Chiloscyphus comprises 25. The spline narrows gradually 

to form a shank usually made up of 6 long 

tubules. The anterior basal body (ABB) occupies a 

subapical position; the triplet extensions of the 

posterior basal body (PBB) extend forward and overlap 

with the ABB. The anterior mitochondrion (AM) 

follows closely the outline of the LS and may extend 

posteriorly beyond the LS where it then underlies 

the spline. The posterior mitochondrion, in certain 

sections, is seen to nearly ensheath the spherical, 

starch-containing plastid, a condition more commonly 

seen in mosses. The starch grains show a clumped 

arrangement. In contrast, the spermatids of Marsupella, 

the only other jungermannialian genus to be 

studied in detail, show no overlap of the ABB and the 

PBB or their extensions and the starch grains are 

linearly arranged in the plastid. 

SCHAFFER, KAREN L. Department of Botany, 

University of Iowa, Iowa City, IA 52242. 

- Development of papillae on stem leaves of 

Thuidium delicatulum (Hedw.)BSG. 

The development of papillae on upper cells of stem 

leaves of Thuidium delicatulum was investigated with 

light, scanning and transmission electron microscopy. 

Initially, through a combination of cell wall depo- 

sition and expansion, a small protuberance forms in 

the central portion of the cell wall. At this point 

the cell wall is very thin, but inner and outer 

layers are differentiated. The protoplast extends 

into the lumen of the developing papilla. As a 

result of further deposition of inner cell wall 

material, the papilla continues to enlarge and there 

is a progressive thickening of the entire cell wall. 

Associated with this stage is the occurrence of 

tubular vesicles that originate inside the proto- 

plast and possibly contain wall precursor material. 

These vesicles are closely associated with the 

plasmalemma. Also, microfibril formation has been 

observed on the side of the plasmalemma adjacent to 

the cell wall. Ultimately, the papillae are more- 

or-less solid structures that are composed primarily 

of inner wall material. Although the papillae that 

occur on mature stem leaf cells of Thuidium 

delicatulum are simple, the developmental stages are 

fundmentally the same as those that have been es- 

tablished previously for the branched papillae 

that characterize upper leaf cells of Anomodon 

attenuatus (Hedw.) Hub.


SHAW, A. JONATHAN. Herbarium, University of 

Michigan, Ann Arbor, MI 48109 - Peristome 

Morphology and Homology in Mielichhoferia. 

The peristome of M. mielichhoferi has traditionally 

been considered single and endostomial. However, 

new observations provide evidence that it is 

double, consisting of more or less well-developed 

exostome teeth and a rudimentary, endostomial 

basal membrane. Other Mielichhoferia species 

whose peristomes have been incorrectly interpreted 

as single and endostomial include M. himalayana, 

M. macrocarpa, and M. lahulensis. Many tropical 

Mielichhoferias do have peristomes consisting of 

endostome only, but there is much variation in 

structural detail. Observations on Mielichhoferia, 

as well as selected other diplolepideous taxa, 

support Philibert's contention that the endostome 

is two layered, consisting of inner and outer cell 

wall plates. 

SIGAL, LORENE L. Oak Ridge National Laboratory, 

P.O. Box X, Oak Ridge, TN 37830.1 - Lichen 

research and regulatory decisions. 

During recent years, in response to an increased 

awareness of the adverse consequences of air 

pollution, the government has enacted legislation 

that is of interest to lichenologists. This report 

discusses the role that lichen research has had in 

the development of this legislation or in decisions 

made as a result of the legislation. The major acts 

of interest are the National Environmental Policy 

Act of 1969 and the Clean Air Act Amendments of 1970 

and 1977. Under the Clean Air Act, the Environmental 

Protection Agency established the National Ambient 

Air Quality Standards, the Prevention of Significant 

Deterioration class I, II, III areas, and the 

"adverse impact" determination for class I areas. 

In order to make enlightened decisions on 

environmental issues related to these regulations, 

data are needed that define: 1) terminology such as 

"adverse impact," acceptability, significance, 

reversibility, etc.; 2) dose-response functions, 

including chronic effects and effects of pollutant 

combinations; 3) differential sensitivities of 

species; 4) abundance of natural populations; 

5) understanding of inter- and intra-specific 

relations; and 6) the role of the organism in the 

structure and function of ecosystems. Lichen 

research has addressed some of the preceding points, 

but the necessary data for others are lacking. 

Evaluation of existing research has identified 

information gaps and suggested avenues of future 

research not only for lichenologists interested in 

air pollution but also for those interested in 

ecology, population biology, and physiology. 

1Operated by Union Carbide Corporation under contract 

W-7405-eng-26 with the U.S. Department of Energy. 

SMITH, CLIFFORD W.* & WILLIAM J. HOE. Department 

of Botany, University of Hawaii at Manoa, 3190 

Maile Way, Honolulu, HI 96822, and Herbarium 

Pacificum, Bishop Museum, P.O. Box 19000-A, 

Honolulu, HI 96819. - Bryophytes and lichens atop 

Mauna Kea, Hawaii. 

Mauna Kea above 13,000 ft. is a bleak area which had 

remained relatively unaffected by modern civilization 

until it became the site of several astronomical 

observatories. It is an ideal site for such studies 

because of its general aridity and unpolluted 

atmosphere. A survey conducted to provide baseline 

information for an environmental impact statement 

for further development of the area demostrated the 

presence of 11 mosses (including one new species) and 

22 lichens. No liverworts were found. Six species 

were new records to the Hawaiian Islands. Most 

species are found in highly protected areas though 

Umbilicaria hawaiiensis and Pseudephebe pubescens are 

found on rock faces fully exposed to the prevailing 

winds. The cinder cones were poor habitat except in 

spatter ramparts. The lava flows supported the 

richest flora particularly on west-facing aspects. 

Lake Waiau, a permanent lake at 13,000 ft. on the 

south side of the mountain, had a very poor flora 

even though the area is immersed in late afternoon 

fog particularly in the summertime. The absence of 

fruticose species in this situation may be the result 

of freezing temperatures every night of the year. 

STARK, LLOYD R. Department of Biology, 202 

Buckhout Laboratory, The Pennsylvania State 

University, University Park, PA 16802. - Life 

history studies on Forsstroemia trichomitria 

(Hedw.) Lindb. (Cryphaeaceae). 

Populations of Forsstroemia trichomitria in central 

Virginia initiate perigonia and perichaetia along 

same stems during June. Inflorescences are produced 

on current cycle stems only, and maturation of 

inflorescences is acropetal. In most cases, the 

arrangement of inflorescences is gonioautoicous. The 

interval of fertilization extends from mid-August 

through September, with young embryos first observed 

in September. These embryos are hyaline for several 

weeks and exhibit very slow development. Near the 

onset of winter, the embryos cease growing and become 

chlorophyllose. Both stem and sporophyte elongation 

are apparently negligible during the winter months. 

Resumption of growth in the spring entails renewed 

embryonic and stem elongation. The embryonic phase 

is broken near the end of July, as setae elongate. 

Capsule expansion begins shortly thereafter, extending 

through September. Spore development is slow, and 

opercula do not fall until February of the ensuing 

winter. Thus while a set of gametangia is initiated 

and matured in the same growing season, sporophyte 

maturation takes approximately 17 months. Hence, 

during the months of September-February, two sporo- 

phyte generations occur simultaneously on the same 

stem. 

THOMAS, R. J.* and JAMES G. ELLIS. Department of 

Biology, Bates College, Lewiston, ME 04240. 

- Phototropic curvature of Pellia sporophytes. 

Positive phototropic curvature of elongating liver- 

wort sporophytes was described by Askenasy as early 

as 1874, but has only been studied sporadically since 

that time. The response is of interest in that: (1) 

it is rapid (occurring within 20-60 minutes after ex- 

posure to unilateral illumination); (2) it is sensi- 

tive (blue wavelengths of light being the most effec- 

tive); and (3) it is not possible to separate the re- 

sponse from the site of perception. Removal of api- 

cal spore capsules from Pellia epiphylla sporophytes, 

for example, has little effect on the phototropic re- 

sponses of sporophyte stalks. Localized unilateral 

illumination of sporophyte stalks results in curva- 

ture at the point of illumination only, with no 

transmission of the stimulus. Acid ef flux, as deter- 

mined by agar-dye techniques (Mulkey and Evans, 1981 

- Science), is also associated with localized regions 

of curvature. Owing to (1) the simulation of curva- 

ture using localized application of indole-3-acidic 

acid in lanolin paste, and (2) a presumed relation-

ship between auxin concentration and H+ efflux 

(Rayle, 1973 - Planta), we postulate a mechanism for 

phototropism based on change in relative hormone con- 

centrations between opposite sides of these struc- 

tures. 

WEBSTER, HAROLD J. Biology Department, 

DuBois Campus, The Pennsylvania State 

University, DuBois, PA 15801 - Elemental 

Analyses of Splachnaceae and Their Sub- 

strates. 

The elemental analyses of field-collected 

plants and their substrates and of labora- 

tory-cultured plants of the Splachnaceae 

provided evidence in reference to the 

nitrophile hypothesis. The Splachnaceae 

exhibit strong affinities for substrates of 

animal origin, which has been suggested as 

a requirement for nitrogen. Owl pellets 

and dung with and without plants of the 

Splachnaceae had relatively high levels of 

N, P, and Ca. Field-collected taxa had 

slightly higher elemental percentages than 

other cold-region bryophytes. The higher 

Ca and P levels reflect substrate contents. 

Tetraplodon mnioides plants had higher Ca, 

P, and N percentages than did the more 

hydric Aplodon wormskjoldii plants. Anal- 

ysis of cultured plants shows no major dif- 

ferences among taxa or among media used, 

although deficiency levels were indicated 

for plants grown on media with low levels 

of Ca, N, and Mg. Comparison of field and 

culture analyses suggests field plants may 

be nitrogen deficient despite the high 

nitrogen content of their substrates. 

Symposium: A Developmental and Structural 

Perspective on Phenotypic Plasticity: A 

Contribution to its Delineation 

INTRODUCTION 

When the concept of phenotypic plasticity is invoked, 

it is usually in reference to the impact of external 

environments on plant form. There are two possible 

ways to view phenotypic plasticity. One is that it 

represents an additional set of developmental events 

induced by the external environment and, in that con- 

text, represents something added to the normal dev- 

elopmental processes in a plant. The other is that 

it is a manifestation of the normal developmental 

events seen in the ontogeny of any plant. It is the 

purpose of this symposim to present information on 

plant development, including that of phenotypically 

plastic systems, to assess which of the two views 

presented above, or any others, are most appropriate 

for understanding phenotypic plasticity. An under- 

standing of the underlying basis for phenotypic 

plasticity is of significance in attempting to ex- 

plain the evolutionary and developmental consequences 

of its existence. 

Organized by Jack Maze, University of British Colum- 

bia, Vancouver, BC. 

Developmental and Structural Section 9 

WHITTIER, 1R. O., H. PRINGLE, H. A. MILLER & B. A. 

WHITTIER. Department of Biological Sciences, 

University of Central Florida, Orlando, FL 32816 

- Matrix analysis for Pacific insular bryogeography. 

Electronic data files established during production 

of the Prodromus Florae Muscorum Polynesiae (1978) 

and the Prodromus Florae Hepaticarum Polynesiae (in 

press) provide a data base containing nomenclatural 

and distributional records for 174 genera and 1,760 

hepatic species, and 254 genera and 1,627 moss 

species, reported on 114 tropical Pacific islands and 

as shared with 49 circum-Pacific and other world 

areas approximating those of Index Muscorum (Wijk et 

al ., 1959-1967). Files kept current on key-punched 

cards for security may be accessed directly by entry 

onto Harris 800 disk files. FORTRAN programs enable 

production of matrices as large as 200 X 200 geographic 

areas. Recoding permits organization into 

smaller condensed geographic groups or regions. These 

matrices display numbers of species reported for an 

island or its archipelago on the diagonal, and at 

matrix intersections in the upper triangle, numbers 

shared by two areas. A lower triangle contains 

indices of similarity. A taxonomic recoding option 

permits similar matrix production for genera. 

Subprograms list (1) families (either alphabetically 

or phylogenetically) with their genera and species, 

or (2) genera and species alone, for any single 

island, group, or for all islands and groups, and can 

ideritify and enumerate reported endemics and their 

percentage of the known bryoflora. Various cluster 

analysis routines carn be applied within the program 

system. Program construction design is such that 

application requires minimal computer experience, and 

permits use of other taxonomic and biogeographic data 

sets (up to 9,999 taxa and 200 geographic areas). 

Conversion to a microcompuiter program system is 

planned. 

DEVELOPMENTAL AND STRUCTURAL SECTION 

FISHER, JACK B. Fairchild Tropical Garden, Miami, 

FL 33156. - Branching patterns and simulations of 

trees: deterministic vs. stochastic models. 

Published attempts at computer modeling of the geom- 

try of tree crowns and rhizomes are reviewed. Deter- 

ministic and stochastic (probabilistic) models are 

contrasted, and the problems associated with each 

method of simulating complex biological patterns are 

noted. Small changes in the elemental parameters of 

branching geometry (branch angles, branch unit 

length) can have major effects on overall crown shape 

after many orders of branching. While stochastic 

simulations produce "realistic" trees, they may not 

be meaningful for ecological or adaptational studies 

since they obscure local specific phenotypic 

responses to environmental or age-dependent condi- 

tions, e.g. sun-shade effects, architectural 

reiteration. 

KAPLAN, DONALD 

R. Department of Botany, 

University of California, Berkeley, CA 94720 

- Heteroblastic development and phenotypic 

plasticity in higher plants. 

Any effort to study environmentally induced changes 

in plant structure (phenotypic plasticity) must be 

done against the background of the normal develop-

10 Developmental and Structural Section 

mental changes expressed during the ontogeny of the 

plant. The term "heteroblastic development" has 

been used to refer to such regular ontogenetic 

changes in plant form. Using recent research on 

the developmental basis of the heteroblastic change 

in leaf form in Acacia, it will be shown that the 

change involves: 1) a regular ontogenetic change 

in proportion of blade to petiole; and 2) a change 

in the type of blade morphology (from pinnate to 

simple) which is independent of its position in the 

shoot and hence a plasticity response. Once a 

clear delineation of the involvement of these two 

components in this heterophylly is made, it can be 

shown that the original distinction between homo- 

blastic and heteroblastic development was falsely 

defined because it was based on the phenotypically 

plastic component. From an analysis of attempts to 

induce juvenile types of foliage in adult plants, 

using hormones such as gibberellic acid, it is 

suggested that many of the responses may be examples 

of phenotypic plasticity and not a true reversal of 

the developmental phase. The significance of these 

conclusions for the evaluation of hormone roles in 

phase changes in plants will be discussed. 

PAOLILLO, D. J., JR. AND GAIL RUBIN. Section of 

Plant Biology, Cornell University, Ithaca, NY 

14853. - Environmental plasticity of sexual 

phenotypes in Onoclea sensibilis.. 

Young Onoclea gametophytes become male in abundance 

when grown on their native soil but are inhibited 

from expressing maleness when grown in axenic 

cultures on agar. Classical experiments designed to 

test the action of antheridiogens using agar-grown 

Onoclea gametophytes are logically restricted to the 

explanation of laboratory anomalies because the 

control plants do not resemble field-grown organisms. 

Most soil-grown plants become male, without the 

intervention of antheridiogens, after attaining their 

meristems and becomingsmall hearts. On agar, female- 

ness is more prominent but some heart-shaped gameto- 

phytes become male at the same time their cohorts 

become female. Thus, the concept that a meristem 

is antithetic to maleness is also related to labora- 

tory artifacts. On agar, dark-grown gametophytes 

become male at the same time as light-grown gameto- 

phytes. Male plants in the dark are small filaments. 

Thus, neither the meristem nor the morphological 

state of the organism appears to bear a direct, 

causal relationship to maleness. Likewise, there is 

no basis for the concept that the action of antheri- 

diogens in Onoclea is to overcome a light-induced 

block to maleness. It remains possible, however, 

that the action of applied antheridiogen is antagon- 

ized by light in Onoclea. However, these and all 

other conclusions based on agar cultures must be 

interpreted with a fuller knowledge of the limits of 

phenotypic plasticity when Onoclea is the test 

organi sm. 

Richards, J.H. Dept. of Biol., Fla. Inter- 

national U., Miami, FL 33199. Developmen- 

tal basis of leaf plasticity in Eichhornia 

crassipes Solms. (Pontederiaceae). 

In 1965 A.D. Bradshaw defined plasticity as 

the "amount by which the expression of indiv- 

idual characteristics of a genotype are chan- 

ged by different environments." Such change 

requires some change in development of that 

characteristic. Leaf development was studied 

in a clonal mat of water hyacinth in order to 

quantify parameters which show variability 

and to document the developmental basis of 

divergence in form. The mat environment var- 

ies from the mat edge to center. Leaves on 

plants inside the mat differ in petiole 

length, lamina length, petiole width and lam- 

ina width from leaves on the mat edge. Dif- 

ferences are not a function of plant age 

alone. Leaf shape parameters have different 

variances between the two environments--pet- 

iole measurements display more variability 

than lamina. When development of the two 

leaf types is compared, they show parallel 

relative growth rates for leaves less than 

2.5 mm. Divergence in form results from dif- 

ferences between leaf types in 1) how long 

growth continues and/or 2) late-developing 

differences in relative growth rates. The 

earliest divergences in relative growth rates 

occur in leaves app. 8 mm long. 

Developmental divergences between these 

plastic leaf types contrasts with developmen- 

tal divergences between invariant leaf types. 

In E. crassipes prophylls and foliage leaves 

are always different in form, regardless of 

environment. These differences, however, are 

present soon after leaf initiation. 

Symposium: Developmental Physiology of 

Flowering 

INTRODUCTION 

The process of flowering can be divided into at 

least five sequential phases; our speakers will re- 

view the subjects of flower induction, flower differ- 

entiation, flower opening, pollination, and flower 

senscence. 

Organized by Ross E. Koning, Rutgers University, Pis- 

cataway, NJ. 

GREYSON, RICHARD I. Department of Plant Sciences, 

University of Western Ontario, London, Ontario. 

N6A 5B7. - Flower primordia - a challenge to 

plant developmental i sts. 

The following phenomena, all described from traditional 

morphological and anatomical viewpoints still 

represent a profound challenge to developmentalists. 

A) Primordia initiation: The relative contributions 

and orientations of cell division and enlargement to 

the setting and establishment of a primordium. 

B) Determination and differentiation: A number of 

different models have been described. Some exhibit 

delayed canalization while others are less easily 

modified. C) Organ growth: From the few analyses 

that do exist, primarily on stamens, one should 

expect considerable variety in the regulatory stimuli 

and the type of cellular response which leads to 

common structures. This variety of mechanism points 

toward considerable parallalism in the evolution of 

the final developmental events. D) Sexual 

differentiation: The exploration of the developmental 

basis of sexual differentiation has proceeded at a 

plant of levels. Perhaps the most popular studies 

impl icate pl ant hormones as causal factors. In 

reviewing these studies we conclude that while in 

some flowers regulation may sharply correlate with 

endogenous levels and activities of hormones, more 

frequently such parallels cannot be identified.

Certainly, no single hormone-based model can be 

presented at present to account for sexual different- 

iation. Studies of protein patterns and other gene- 

product analyses are rare and at present 

inconcl usive. 

HALEVY, ABRAHAM H. Department of Environmental 

Horticulture, The University of California, Davis. 

(on leave from The Hebrew University, Rehovot, 

Israel). 

- Regulation of petal senescence. 

The main growth regulator controlling petal senescence 

of some flowers (e.g., carnations) is ethylene. 

Other flowers (e.g., roses) are much less sensitive 

to ethylene. The most effective inhibitor of senescence 

and abscission in ethylene-sensitive flowers is 

Ag+, applied as Ag-thiosulfate. Cytokinins delay 

petal senescence by inhibiting ethylene biosynthesis. 

Pollination promotes petal senescence. There seems 

to be a multi-stage pollination-induced senescence 

signal. The first one being I-aminocyclopropane-lcarboxylic 

acid (ACC), diffused from the pollen. 

Wound-ethylene and auxin may participate in later 

stages. In both ethylene sensitive and ethylene nonsensitive 

flowers, a decrease in membrane fluidity 

was observed during aging. Environmental or chemical 

agents modifying the rate of senescence, correspondingly 

also altered the rate of change in petal membranes 

fluidity. The decrease in fluidity corresponding 

to an increase in the ratio of free sterols 

to phospholipids, due to a decrease in the content 

of membrane phospholipids. The activity of petal 

ATPase and of sucrose uptake by the petals is correlated 

with membrane fluidity. These processes may 

regulate the reduction in water and dry weight 

content of fading petals. 

KEVAN, PETER G. Department of Environmental 

Biology, University of Guelph, Guelph, Ontario 

NlG 2W1, Canada. 

- Floral characteristics for pollinators. 

Floral attractants appeal to the senses of pollina- 

tors and should be investigated with those in mind. 

Attractants may be visual, as colors, color patterns, 

sizes, outline shapes, and arrangement of floral 

parts. Depth effects, as in tube- and funnel-shaped 

flowers are also involved. Olfactory cues function 

in long- and short-distance attraction of, and in 

flower discrimination by pollinators. Guide patterns 

on flowers may be visual, chemical, and structural 

and aid pollinators in foraging and pollinating. Mi- 

crosculptural features on flowers are distinguished 

by insects which may use them as guides and in plant 

species recognition. Some floral structures benefit 

pollinators by providing shelter and/or warmth. 

Color, form, presentation, and sporophyll placement 

indicate the various pollination syndromes. Correla- 

ted with those are features of pollen and the 

chemical nature and amounts of floral rewards for 

pollinators. 

KONING, ROSS E. Department of Biological Sciences- 

Botany, Rutgers University, Piscataway, NJ 08854. 

- Plant hormones and growth of flower parts during 

flFoweropening. 

There is no simple understanding of the roles of plant 

hormones in control of flower part growth since, until 

recently, no species had been examined for the 


roles of all of the plant hormones, both applied and 

endogenous, in growth of all of the flower parts. 

Such an analysis was recently completed for Gaillardia 

gra randiflora. Three types of measurements weiMade: 

1) growth of the flower parts under natural conditions, 

2) growth of isolated flower parts in response 

to hormones applied in vitro, and 3) the endogenous 

hormone levels. These measurements were correlated 

with each other to determine the roles of the 

various plant growth substances. In Gaillardia, 

corolla elongation occurs by gibberelliT ofrel, ffilament 

and style elongation occur by auxin control, and 

stigma unfolding occurs by ethylene control. The ray 

flower corolla must be fully expanded to attract pollinators 

before the fertile disc flowers open, thus 

explaining need for separate controls. The growth of 

the filaments and the style can be controlled by a 

single hormone; the sequential events are timed by 

the position of the two organs with respect to the 

auxin source: the pollen. As pollen develops, auxin 

is first transported to the filament; only after the 

pollen is shed directly onto the stigma, is the auxin 

transported to the style. The level of auxin in the 

stigma is then high enough to promote the production 

of ethylene and cause stigma unfolding. The tidy 

control mechanism elucidated in Gaillardia probably 

applies only to members of a sma of Asteraceae 

species, since in the literature, unrelated 

plants have different methods of developmental control. 

Future complete studies will provide a basis 

for sorting the seemingly contradictory findings into 

a more systematic understanding of flower part growth. 

LANG, ANTON. MSU-DOE 

Plant Research Laboratory, 

Michigan State University, East Lansing, MI 48824 

- Flower induction: endogenous hormone-like 

factors . 

Evidence for a hormone-like inducer of flower forma- 

tion ("florigen"), which is formed in the leaves 

while acting in the apical shoot meristems, exists 

for about 50 years. Most of it is based on grafting 

experiments between photoperiodic plants maintained 

in the noninductive daylength ("receptors") on one 

hand and similar plants exposed to the inductive day- 

length or dayneutral (DN) plants ("donors") on the 

other. Experiments of this kind have been done in 

eight plant families. It has al so been shown that 

long-day (LD) receptors can be induced to form 

flowers by LD, short-day (SD) and DN donors; SD re- 

ceptors can be induced by SD, LD and DN donors; and 

flower in DN receptors can be hastened by LD and SD 

donors. Donors and receptors can belong to the same 

species, to different species of the same genus, and 

to different genera. Thus, florigen appears to be 

ubiquitous and to be nonspecific in both the taxono- 

mic sense and with respect to the physiological re- 

sponse type. For about 5 years we also have evidence 

for a graft-transmissible inhibitor of flower forma- 

tion ("antiflorigen"), so far in two LD plants. 

Antiflorigen inhibits flower induction in DN and SD 

plants of the same or a different genus; like flori- 

gen it is evidently nonspecific both taxonomically 

and physiologically. Flower induction thus appears 

to involve both promotive and inhibitory, endogenous 

hormone-like factors: florigen which in LD and SD is 

formed only in LD and SD respectively, while in DN 

plants it is formed independent of daylength; and 

antiflorigen which is formed at least in some LD 

plants under SD conditions. This situation will be 

briefly discussed in relation to other aspects of 

f lower i nd ucti on .


Symposium: Homology in Modular 

Organisms-Concepts and Consequences 

INTRODUCTION 

It is proposed that the concept of homology as it 

applies to modular organisms (specifically higher 

plants) be the subject of this symposium. The dis- 

cussion will be timely as the recognition of homolo- 

gous structures is foundational to the application of 

cladistic methods. If the basic assumptions of cla- 

distic analysis can be shown to be well-founded, its 

methodology is strengthened; if it is not, then the 

methodology is likely to lead to erroneous conclusions. 

Clearly also the basic concepts of evolutionary mor- 

phology of higher plants deserves a careful scrutiny 

independent of any influence derived from the study 

of organisms with unitary construction. 

Organized by P.B. Tomlinson, Harvard University, 

Petersham, MA. 

KAPLAN, DONALD R. Department of Botany, 

University of California, 

- The problem of serial 

a case study. 

Berkeley, CA 94720 

homology in higher plants: 

When two different organ forms are produced along 

the higher plant shoot, intermediates between the two 

types typically are formed at the intervening nodes. 

Such transitional forms have been a principal source 

of evidence in determining the structural correspondences 

(serial homology) between the two leaL types. 

Typically most morphologists in the past were content 

to determine such structural relationships from 

the comparison of fully-developed organs rather than 

study their development. In a recent study of the 

developmental basis for the classic case of heterophylly 

in Acacia it was shown that such deductions 

of serial homology based on mature leaf forms led to 

erroneous conclusions of phyllode morphology and 

developmental divergence. The difficulty arose 

because the nature of the change in blade form masked 

the true change in proportion between petiole and 

blade, forcing investigators to rely on blade form 

as an indication of the length of the petiole. 

Underlying much of the erroneous judgement of 

phyllode morphology was the assumption that the 

developmental change proceeded by Goebel's metamorphosis 

concept. Actual comparative developmental 

analysis of serial appendages in seedlings of 

phyllodineous species of Acacia have not only 

negated the metamorphic concept but have underscored 

the necessity of truly comparative developmental 

data for a correct assessment of organ homologies. 

SATTLER, ROLF. Biology Department, 

McGill University, Montreal, Quebec H3A IBl 

- Homology - a continuing challenge. 

According to Sneath and Sokal (1973) morphological 

correspondence and common ancestry are the two 

basic ideas at the root of the many different 

homology concepts which have been proposed. 

Definitions of homology in terms of common ancestry 

have been criticized by many authors for a variety 

of reasons. The other idea of homology which 

refers to morphological correspondence may be based 

on a philosophy of essentialism. Accordingly, two 

structures are homologous whenever they are 

essentially similar. Remane (1952) specified three 

main criteria and a number of auxiliary criteria 

which determine what is meant by essential 

similarity or morphological correspondence. 

Although many structures can be easily homologized 

according to these criteria, difficulties arise 

when different criteria lead to contradictory 

honologizations. A resolution of such difficulties 

is achieved by distinguishing different kinds of 

homology. Other difficulties are resolved by the 

application of a semiquantitative or quantitative 

homology concept which leads to the recognition of 

partial homologies (or partial correspondences) in 

contrast to total homologies (1:1 correspondences). 

STEVENS, Peter F. Harvard University Herbaria, 

22 Divinity Avenue, Cambridge, MA 02138 - Homology 

and plant systematics. 

I discuss aspects of similarity, homology, and the 

relationship between them. (1) The operations by 

which we decide that characters are similar (potent- 

ially homologous) and so usefui in phylogenetic 

analysis are little discussed in recent taxonomic 

literature; we face similar problems irrespective of 

our taxonomic school. These problems include the 

evaluation of conflicting criteria of similarity; 

the reification of terms which may then lead to 

untested assumptions about similarity; and the cri- 

teria used in the delimitation of character states. 

(2) The translation of assessments of simple simi- 

larity to hypotheses of homology, similarity as a 

result of common ancestry, are crucial. The trans- 

lation involves cladistic analysis of all similar 

characters; those derived characters that are con- 

gruent with the best-supported cladogram may be 

hypothesized to be homologies; such hypotheses are 

tested both against new data and more detailed 

studies of the original similarities. In cladistic 

analysis, homology and synapomorphy are synonymous 

and neither can be partial. (3) The relationships 

between organisms, criteria for assessing similarity 

in structure of different organisms, and theories 

concerning the relationships between organisms that 

is decided by some estimate of similarity, are con- 

sidered. Emphasis is placed on the process of re- 

ciprocal illumination in an attempt to evaluate the 

claims of some morphologists and systematists as to 

the historical and/or epistemological priority of 

certain parts of the systematic process. 

TOMLINSON, 

PHILIP B. Harvard University, 

Harvard Forest, Petersham, MA 01366. 

- Homology: An empirical view. 

Comparative morphology in plants is presented as an 

empirical discipline into which "homology" (a set of 

theoretical concepts) is often inserted as an impedi- 

ment to analysis. Problems arise because homology is 

defined and homologous structures are established in 

a variety of ways. A priori rules applied in morpho- 

logical analysis can result in circular reasoning. 

Observation can be relegated to a lower order of 

scientific endeavour, at the expense of theoretical 

analysis. Modular organisms, like the higher plants 

with extended heteroblastic ontogenetic sequences and 

indeterminate addition of parts, offer abundant op- 

portunity for misinterpretation, as compared with 

organisms with unitary construction. Their adaptive 

organization depends on a high degree of plasticity. 

Evolutionary development of plant form is a process 

of "fixing" this plasticity and regenerating it in 

novel ways. A particular confusion is that between 

"'structural similarity" which is a direct result of 

the organization of the individual, and is inherent

in the concept of "serial homology", and the more 

concise notion of strict homology which (by defini- 

tion) is due to descent. A historical perspective is 

particularly illuminating, especially as the basic 

principles of comparative morphology are largely 

conceived in a pre-evolutionary environment. Em- 

phasis will be placed on developmental analysis in 

comparative morphology as a basic process in the 

generation of the modular organism. Knowledge of 

development can frequently illuminate comparative 

analysis. Examples will be cited where the organiza- 

tional plasticity almost defeats the possibility of 

evolutionary morphological analysis in modular organ- 

isms. 

W. H. WAGNER, JR., Department of Botany, University 

of Michigan, Ann Arbor, Michigan 48109. - 

Homology and the early 

plants. 

diversification of vascular 

Primitive vascular plants are the ones that first appeared 

in the fossil record, that possess simple life 

cycles,and are most similar to the outside group, the 

bryophytes. Because of their diversity, homology of 

even major organs has been controversial. Theories 

like the Stelar Theory or the Telome Theory try to 

fit the morphics of plants into preconceived molds 

Objectivity is best accomplished by using classical 

tests of position, ontogeny, mature structure, and 

absence of intermediates. Evidence of early diversification 

of vascular plants comes from cladistic analysis 

of living groups, psilotopsids, lycopsids, 

equisetopsids, and polypodiopsids, together with the 

fossil remains of trimerophytes, zosterophytes, and 

rhyniophytes, a motley assemblage. Our problem is 

to connect different organs in different groups, because 

there are such large gaps, and intermediate 

stages or trends are lacking. How teratology fits 

into this is a question. In addition to varlous tissue 

types, the major organs are discussed:stem, root, 

leaf, sporangium, spore, gametophyte, gametangia, 

gametes, embryo, and foot. Because of homoplasy, 

homology is, by itself, not necessarily a criterion 

of relationship. At the tissue level, the stele provides 

a challenge; at the organ level, the foliar 

appendages. Parsimony suggests that at least in the 

case of the leaf, all of the appendages were originally 

emergences. The position of sporangia, so fundamental, 

apparently, in the early differentiation 

of vascular plants, is a good example, of the absence 

of intermediates, suggesting abrupt, rapid changes. 

There is a spectrum of degrees 

organs of early vascular plants 

to very questionable. 

of homology of the 

-- from very obvious 


BASILE, DOMINICK V. and MARGARET R. BASILE 

Department of Biological Sciences, H. H. 

Lehman College of CUNY, Bronx, N.Y. 10468. 

- Auxin antagonist-induced desuppression 

of leaf primordia of Plagiochila arctica 

(Hepaticae): Possible integration of 

auxin, ethylene and hydroxyproline-alterable 

proteins in correlative control of 

cellular suppression. 

Two inhibitors of auxin transport, triiodobenzoic 

acid (TIBA) and N-l-naphthylphthalamic 

acid 

auxin action, i - 

(NPA), and an inhibitor of 

(p-chlorophenoxy) isobutyric 

acid (PCIB), induced the same kind of pheno- 


variation in Plagiochila arctica Bryhn & 

Kaal. (Hepaticae) as do antagonists of ethy- 

lene synthesis/action and antagonists of 

hydroxyproline-protein (hyp-protein) syn- 

thesis. This indicates that the two phyto- 

hormones and a cell surface protein sensi- 

tive to antagonists of hyp-protein synthesis 

play an integrated role in the correlative 

control of cellular suppression - primordium 

development. Auxin-induced ethylene syn- 

thesis and ethylene-induced cell surface 

hydroxyproline protein deposition correlated 

with suppressed development have been re- 

ported byothers, previously. This, however, 

is the first experimental evidence to impli- 

cate all three molecules, two phytohormones 

and a cell surface glycoprotein, in the same 

morphoregulatory system. This correlative 

control system conceivably plays an impor- 

tany role in other, if not all, groups of 

land plants (Embryophyta). 

CAESAR, J. C. AND A. D. MACDONALD*. Department 

of Biology, Lakehead University, Thunder Bay, 

Ontario. P7B 5EI. 

- Comparison of early growth of vegetative and 

reproductive short shoots of Betula papyrifera. 

This study shows the cost to short shoot growth of 

female inflorescence development. Expanding and 

flushing short shoot buds were collected from mature 

trees from April-June 1982. Quantitative analyses 

were made on fresh and FAA-fixed material for 

relative growth rates (RGR) of leaves and buds, 

specific leaf area (SLA), leaf area ratio (LAR), leaf 

area (LA) and number of leaf side nerve pairs (SNP). 

Material was partially dissected to determine whether 

the bud was reproductive or vegetative. Short shoot 

buds may be vegetative or may bear a female 

inflorescence; these buds may be proximal on a long 

shoot or terminal on a short shoot. Axillary short 

shoot buds flush later than 2-4 year old short shoot 

terminal buds, which flush later than 5-10 year old 

shoots. Mean RGR of 5-10 year old short shoot buds 

is greater than that of younger short-shoot buds. It 

is suggested that older short shoot buds are 

relatively autonomous and that the flushing long 

shoot exhibits an inhibitory influence on the 

proximal axillary buds and possibly on young short 

shoot terminal buds. Reproductive short shoots diffr 

from vegetative short shoots in that they have lower 

LAR's and leaf RGR's, higher SLA's, smaller LA's, 

fewer SNP's and they seem to grow more in length 

than in width. These findings are related to 

reproductive cost. The developing inflorescences 

act as preferred 'sinks' for resource allocation. 

CECICH, ROBERT A. Forestry Sciences Laboratory, 

P.O. Box 898, Rhinelander, WI 54501 - 

Histochemical and ultrastructural changes in 

microsporangia of jack pine during the winter. 

The development of jack pine (Pinus banksiana Lamb.) 

microsporangia from October to April was investigated. 

DNA, RNA, and protein content of sporogenous 

cells was measured with a microdensitometer at 

monthly intervals. DNA was unreplicated (2c) until 

March when DNA synthesis was first noted, coinciding 

with a loss of condensed chromatin. Protein staini 

ng i ncreased i n Apri . RNA stai-n i ng i ncreased i n 

December, followed by a loss of staining in January.


Numerous stacks of rough endoplasmic reticulum (RER) 

and lipid bodies first appeared in the sporogenous 

cells in December and may be related to the increase 

in RNA. The RER stacks were only occasionally seen 

in the March collection. Lipid bodies were abundant 

in the tapetal and primary wall cells throughout the 

period of study. The apparent incorporation of 

lipids into the plasmalemma of those two cell types 

was noted in November. An unidentified cytoplasmic 

structure, without a bounding membrane, was abundant 

from November through March. Golgi bodies, abundant 

in October, were rarely seen again until March. 

Microbodies were abundant in March when starch was 

first noted in the plastids. Observations substan- 

tiate reports that winter is not a time for 

cessation of development. 

DOBBINS, DAVID R. & HARRY ALDEN. Biology Dept., 

Millersville University, Millersville, PA 17551, 

& Dept. of Botany, University of California, 

Davie, CA 95616. - Development of the shoot 

system in Marcgravia rectifolia L. 

Marcgravia rectifolia L. is a dimormorphic vine 

having distinct juvenile and adult shoots. The 

juvenile shoot is a climber characterized by an 

orthotropic growth habit. Its stem is very flatten- 

ed and has numerous adventitious roots along the 

stem edges. In contrast, the adult shoot has a 

plagiotropic growth habit, a cylindrical stem and 

no adventitious rootb. Both phases have distichous 

phyllotaxy, but the plastochron is shorter for the 

adult phase than for the juvenile phase. The 

mature leaf of the juvenile shoot is ovate while 

that of the adult shoot is lanceolate. 

Developmentally, the flattened stem of the 

juvenile results from differential production of 

cells primarily in the pith region. Internodes 

of the adult phase are longer than those of the 

juvenile. The longer internodes are a result of 

more cell production rather than greater cell 

expansion. The juvenile phase can change into 

the adult phase and the adult phase can revert 

to the juvenile phase with equal frequency. 

GREEN-PENNINGTON, J.K.*, P.E. RICHARDSON AND R.L. 

BURTON. Department of Botany and Microbiology, and 

Department of Entomology and USDA, Oklahoma State 

University, Stillwater, OK 74074 - Evaluation of 

silicon levels surrounding the penetration site of 

two biotypes of aphid in the leaves of a susceptible 

and resistant strain of barley 

Silicon deposits are naturally occurring in the node, 

internode and leaves of barley. Deposition has been 

found in epidermal cells, sclerenchyma, mesophyll and 

xylem elements. Silicon may be found in impregnations 

of the secondary wall or in opaline silica 

deposits filling the entire lumen of the cell. Preliminary 

study indicates an increase in the level of 

silicon surrounding the penetration sites of the 

aphid. Two biotypes (C and E) of the aphid Schizaphis 

qrarninum (Rondani) were studied on a susceptible 

(Rogers) and a resistant (Will) strain of Hordeum 

vulgare. Aphids were allowed to feed for approximately 

one hour. Samples were taken at time intervals 

and prepared for study under the light microscope, 

SEM, and electron probe x-ray microanalyser. 

MACDONALD, A.D.* AND D. H. MOTHERSILL. Department 

of Biology, Lakehead University, Thunder Bay, 

Ontario P7B 5E1. 

- Short shoot organogenesis in Betula papyrifera. 

This study describes the sequence and chronology of 

inception and development of structures associated 

with various short shoot buds, which include: 1. 

axillary short shoot buds (proximal axillary buds 

on long shoots), 2. terminal vegetative bud, 3. 

terminal reproductive bud, 4. short shoot axillary 

bud (forms on a flowering short shoot). Developing 

and expanding buds were collected from mature trees 

from April to September in 1980-1982, fixed in FAA, 

dissected, stained with fast green and photographed 

with an epi-microscope. Drawings of long and short 

shoots were made from photocopied fresh material. 

Silhouette drawing of bud parts were prepared with a 

camera lucida. An axillary short shoot apex forms in 

year n, appendages are initiated in n + 1, flushing 

occurs in n + 2. This apex forms a terminal bud 

after bud burst. Floral induction may occur in late 

June, year n + 1, or any subsequent year. All buds 

possess 1-3 embryonic foliage leaves, initiated in 

May-June and a fixed number of rudimentary leaves 

which arise in late June-July. Stipules of the 

latter form bud scales of the succeeding bud. 

Pattern of foliage leaf formation followed by 

inception of 3 rudimentary leaves may repeat for 

several years for the successive development of 

terminal buds. Flowering breaks the repetitive 

sequence and an axillary bud forms in the axil of a 

foliage leaf. Buds are determined as incipient long 

or short shoots during bud development, in early July, 

but this may be altered at flushing. 

SEKHAR, K.N. CHANDRA* 

and VIPEN K. SAWHNEY. 

Department of Biology, University of Saskatchewan, 

Saskatoon, Sask., S7N OWO, Canada. - Comparative 

studies of vegetative shoot apices of the sclan- 

ifolium mutant and normal plants of tomato. 

We are using single gene mutants to investigate the 

factors which regulate the genetic expression in the 

leaf and flower development. In the mutant Solani- 

folium (sf/sf), the development of both leaves and 

flowers is affected. The leaves produced had entire 

margins in contrast to the dentate margins of the 

normal plants and the mutant flowers had free sepals, 

petals, stamens and split carpels as opposed to the 

partly fused sepals and petals and united anthers 

and carpels of normal plants. In order to establish 

the stage at which the differences between the two 

genotypes appear, vegetative shoot apices of both 

types of plants were studied with the LM, SEM and 

TEM. The LM and SEM studies showed differences in 

the time of initiation of leaflet primordia; in the 

normal plants leaflet primordia were initiated on 

the P3 leaf primordia while in the mutant plants 

leaflet primordia were initiated on P4. TEM studies 

of the apical meristems showed the following features 

common to both types of plants: meristems with a two 

layered tunica; cells of T1 with large distal 

vacuoles containing electron dense structures and 

cells of Ti and differentiating cells containing 

chloroplasts with proteinaceons bodies - the pret- 

hylakoidal bodies. The only significant difference 

observed between the two genotypes was the presence 

of microbodies near the axils of the leaf primordia 

of mutant plants. These studies show that morpho- 

logical and some fine structural differences are 

detectable early in the ontogeny of leaves of the 

two genotypes.


ALLEN, RANDY D.*, DAVID A. PRIER AND LOUIS 

H. BRAGG. Department of Biology, Texas A&M 

University, College Station, TX 77843 and 

Department of Biology, University of Texas 

at Arlington, Arlington, TX 76019. 

-Ultrastructure of Prosopis glandulosa cotyledon 

cells during storage mobilization. 

Cotyledon cells of Prosopis contain numerous large 

protein bodies which are closely surrounded by a 

single layer of minute lipid bodies. Lipid bodies 

also line the inner face of the plasmalemma. After 

germination, the protein body matrix first develops 

a granular appearance. Later, electron transparent 

regions form, usually at the protein body periphery. 

These areas are memibrane botnd and have been termed 

"Protein body vacuoles." These areas swell and may 

become much larger than the original protein bodies. 

Electron dense protein body fragments remain within 

the protein body vacuoles. Fusion of protein body 

vacuole areas eventually results in the formation 

of a large main cell vacuole which still contains 

spherical fragments of undigested storage protein. 

Lipid bodies enlarge slightly but retain their 

position around protein bodies until enlargement 

of the protein body vacuole. Some evidence of lipid 

body fusion is seen and fewer, larger lipid bodies 

are observed in cells at later stages of development. 

ALMOUSAWI, A.H., P.E. RICHARDSON,* R.L. BURTON. 

Department of Entomology and Botany, Oklahoma State 

University, Stillwater, OK 74078 - The Ultrastruc- 

ture of Greenbug Feeding Damage in Susceptible and 

Resistant Wheat Cultivars. 

Cell and tissue differences resulted when biotype C 

greenbugs Schizaphis graminum (Rondani) fed on 

susceptible as opposed to resistant wheat cultivars. 

There were two different types of cell damage in the 

susceptible cultivar (TAM W-101). Adjacent to aphid 

feeding tracks in vascular bundles there was exten- 

sive and rapid damage to a few phloem cells and 

their contents. In a second type of damaged area 

there was slower degeneration of organelles of meso- 

phyll parenchyma cells in areas traversed by the 

tracks. Chloroplasts lost all membrane structure. 

Later, vesicles appeared in mitochondrial cristae and 

in the nuclear envelope. Dense sheath material was 

located in many feeding sites. Resistant wheat 

(Amigo x TAM W-101) was symptomless at 10 days post- 

infestation. At two days there were a few patches 

of scattered collapsed dried mesophyll cells sur- 

rounded by many unaffected cells. Salavary sheath 

material was found at 2 days post-infestation but 

not later. Feeding tracks in susceptible wheat are 

mostly intercellular with feeding in the phloem. 

Feeding damage to the resistant variety was mainly to 

mesophyll, was slight, and appeared to result in 

little persistant damage. There were no physical 

structural differences between varieties, and dif- 

ferences in extent and types of feeding tracks and 

damaged cells appeared to reflect genetic, physio- 

logical, and biochemical differences. 

ANDERSON, LORAN C. Department of Biological 

Science, Florida State University, Tallahassee, 

FL 32306.--Neotenic expression in Gordonia stomata. 

The Loblolly Bay, G. lasianthus (Theaceae), is a 

medium-sized evergeen tree. Large buttressed peri- 

stomatal rims characterize the stomata. Extensive 


survey for stomatal variation throughout the species ' 

range found that a few trees had a strikingly different 

cuticular pattern around the stomata (concentric rings 

of striae rather than buttressed cups). Seeds were 

germinated from plants having the standard buttressed 

cup cuticles. Stomata of cotyledons lack cuticular 

relief; seedling leaves are sequentially more elaborate in 

cuticular build-up until eventually they achieve the 

striate pattern seen rarely on older (neotenous) trees. 

Root sprouts, on mature "standard pattern" trees, have 

the juvenile cuticular pattern as well. The general tree 

age for switching to cuticles with buttressed 

peristomatal cups has not been determined. 

ARMSTRONG, JOSEPH E. Department of Biological 

Sciences, Illinois State University, Normal, IL 

61761. - The comparative floral anatomy of the 

Solanaceae. 

There have been relatively few studies of floral 

anatomy in the Solanaceae and none of the broad, 

comprehensive studies necessary for comparative study 

of the systematics and phylogeny of this family. A 

preliminary survey of floral anatomy in the 

Solanaceae was recently undertaken to provide a basis 

for further studies. The vascular anatomy and histology 

of the floral organs provided numerous characters 

and character states of potential systematic 

usefulness. Preliminary observations support the 

recognition of two subfamilies, Solanoideae and 

Cestroideae, and also supports their proposed relative 

level of phylogenetic specialization. Anatomical 

characters support the recognition of the endemic 

Australian genera as the tribe Anthocercideae. The 

Lycieae and Nicotianeae are similarly distinct tribes 

based on anatomical characters. Floral anatomy does 

not support the recognition of the Nolanaceae as a 

separate family. 

ARNOTT, HOWARD 3.* and MARY ALICE WEBB. 

Department of Biology, The University of Texas at 

Arlington, Arlington, TX 76019-0498. - Calcium oxa- 

late crystal development in a fungus found in pine 

beetle mines in the cambial zone of Pinus ponderosa 

The production of calcium oxalate crystals by fungal 

hyphae has been established for almost a century (De 

Bary, 1887), but up to now only a few examples have been 

studied with electron microscopy. In the present case we 

have studied a fungus found growing in association with a 

pine beetle that bored through the cambial region of Pinus 

ponderosa logs collected in Pagosa Springs, Colorado. The 

fungus produces clamp connections and is therefore a 

basidiomycete, but is otherwise not yet identified. The 

fungus produces a white mat in the beetle mines, both in 

association with the bark and the beetle excrement. In 

many areas the white mat is many hyphal layers thick. 

Calcium oxalate dihydrate (Weddellite) is produced by the 

hyphae in three ways. 1) Single bipyramidal crystals 

develop along the surface of the hyphae. 2) An encrusta- 

tion of many small interpenetrant twins is produced along 

segments of hyphae. 3) Druse-like multiple interpene- 

trant twins are also found. Many of these druse-like 

bodies are produced as terminations of main hyphae or 

terminations of short lateral hyphal branches. Occa- 

sionally the druse-like bodies are produced on one side of 

a hypha similar to those reported by Arnott (1983). TEM 

and SEM observations on the development of these three 

forms of calcification will be presented and discussed. De 

Bary, A. 1887. Comparative Morphology and Biology of 

Fungi, Mycetozoa and Bacteria. Clarendon Press, Oxford; 

Arnott, H. J. Calcium oxalate (Weddellite) crystals in 

forest litter. Scanning Elect. Microsc., 1983. III: 1141- 

1149.


BARKER, W. GEORGE. Department of Botany and 

Genetics, University of Guelph, Guelph, ON 

NlG 2W1. 

- Further observations on the regenerative 

pattern of Impatiens balsamini L. seedlings 

following mutilations. 

In continued studies on regenerative behaviour of 

seedlings of Impatiens balsamini L., garden balsam, 

additional patterns have been identified. The seeds 

now available exhibit after germination the same 

developmental sequences as those discussed (Annals 

of Botany 47:661, 1981) but the events occur more 

rapidly than reported. Additionally, a series of 

further experiments discloses other behaviours of 

this plant following seedling mutilations. The 

ability to form a regenerated collet is minimized 

and lost as the seedling ages. The tendency to form 

roots in the area basipetal to the excised collet 

persists as seedlings mature but without the 

encircling collet swelling and without associated 

hairs. Single roots become more common than the 

four earlier noted. In seedlings of ca. 6.0 cm in 

total length the rooting after mutilation is quite 

distinctive if the excising cut is made immediately 

behind the collet, midway between collet and 

cotyledon and adjacent to cotyledons. 

It is quite apparent that the control leading to 

the regeneration of the collet-root complex is 

diminished with physiological age. 

BARKER,* W. GEORGE, and HUSSEY, D. BLAINE. 

Department of Botany and Genetics, University of 

Guelph, Guelph, ON NlG 2W1. 

- The initiation of lateral root primordia during 

the early development of seeds in Impatiens 

balsamina L. 

Impatiens balsamina L. seedlings produce a swollen 

encircling ring, the collet basipetal to the root 

apical meristem. From this four lateral roots 

emerge promptly after germination. As recently 

reported (Annals of Botany 47-661, 1951), mutilation 

of seedling by excision of the collet-radical-lateral 

root apparatus will result in the regeneration of a 

basal encircling swelling from which four lateral 

roots and root hairs will emerge (regenerated 

collet). Present evidence suggests that this 

regeneration requires the presence of cotyledonary 

tissue. 

It was considered central to further work on 

lateral root development in garden balsam to 

establish the normal pattern of development of the 

collet-lateral root complex. To this end plants 

were grown in the greenhouse and sections were made 

of developmental stages subsequent to fertilization 

and including the visual appearance of the collet 

subsequent to germination. It is apparent that the 

essence of the collet complex was present very early 

in the development of the embryo. 

BENDA, G. T. A. U.S. Sugarcane Field Laboratory, 

Box 470, Houma, LA 70361. -Leaf-base overlap in 

subtending leaves and bud scales of a sugarcane 

clone. 

The sequence of direction of overlap of leaf bases 

was determined for groups of four leaves, each group 

consisting of the subtending leaf and the three 

oldest scale leaves of the main bud in its axil. A 

total of 380 nodes was examined from 10 greenhouse- 

grown shoots, 15 to 18 months of age, of a sugarcane 

clone (Saccharum interspecific hybrid, CP 68-413) 

selected because of the frequent occurrence of one or 

two supernumerary buds per node. The sequence was 

identified unequivocally for 244 groups. The 

subtending leaves (lv) had 120 of an expected 122 

leaf bases which overlapped to the left, the oldest 

scale leaves (sl), 117, the second-oldest scale 

leaves (s2), 112, and the third-oldest scale leaves 

(s3), 132. The direction of overlap was the same 

for lv and sl in 65% of the groups, for s1 and 

S2 in 56%, and for s2 and s3 in 39%. When the 

groups were classified according to the sequence of 

direction of overlap from lv to s3, all classes 

corresponding to the 16 permutations had some groups, 

but the distribution among classes was not uniform. 

When these classes were assigned to five combina- 

tions, the number of groups in each were as follows: 

all left (14), three left-one right (61), two left- 

two right (89), one left-three right (64), all right 

(16). These results agree with those p'redicted from 

the binomial formula for equal probability of overlap 

in either direction. When the direction of overlap 

of s1 was compared for the main.and supernumerary 

bud of 98 two-budded nodes, the results showed that 

it was the same for 50 and opposite for 48 pairs. 

These results demonstrate that the sequence of 

direction of overlap in this clone does not follow a 

standard pattern of development such as a sequential 

alternation of direction. 

BRAGG, LOUIS H. Biology Department, University 

of Texas at Arlington, Arlington, TX 76019. 

- The testa, hilum, and tracheoids of selected 

Lupinus seeds. 

Seeds of Lupinus texensis Hook., L. subcarnosus 

Hook., and L. havardii S. Wats. were examined with 

scanning electron microscopy for characters that 

would separate them at the species level. Varia- 

tions of the basic simple-foveolate pattern of the 

testa were distinctively different for each species 

with minor exceptions. This basic pattern has been 

unreported for the genus. The hila shapes are 

species characteristic as well. The tracheid bar 

is the most common type found in the subfamiLy but 

possesses tracheoid variations between these species. 

Usefulness of the testa and the hilum as taxonomic 

characters is suggested. 

BROWN, ROY C. and BETTY E. LEMMON. Department of 

Biology, University of Southwestern Louisiana, 

Lafayette, LA 70504 - Microtubule organization 

and morphogenesis in young spores of the' moss 

Tetraphis pellucida Hedw. 

Microtubule systems appear sequentially at the distal 

and proximal poles of tetrad members during mid- 

sporogenesis in the moss Tetraphis pellucida Hedw. 

The distal microtubule system, which'appears immedi- 

ately after cytokinesis, emanates from a microtubule 

organizing center (MTOC) located between the single 

plastid and the nucleus. Whereas the distal system 

is ephemeral, the proximal microtubule system, which 

appears slightly later than the distal system, is a 

more stable component of mid-sporogenesis. The prox- 

imal MTOC is an irregularly lobed, patelliform aggre- 

gation of electron-dense granules located beneath the 

plasma membrane at the proximal spore pole. Several 

bundles of microtubules radiate from the proximal 

MTOC and traverse the cell, enclosing the nucleus in 

a cone of microtubules. The proximal microtubule 

system is thought to function in aperture development 

and organelle migration. The nucleus migrates to the 

proximal pole early in the tetrad stage and maintains

its acentric position throughout later stages of 

sporogenesis. The plastid migrates later in the 

tetrad stage from its meiotic position parallel to 

the distal surface to a position perpendicular to the 

distal surface with one tip in close proximity to the 

proximal MTOC. The proximal microtubule system 

reaches its maximum development by the end of the 

tetrad stage and all micrographic evidence of it is 

lost in the maturation stages of late sporogenesis. 

BRUCK, DAVID K. and DAN B. WALKER. Department 

of Biology, UCLA, Los Angeles, CA 90024 

- Epidermal commitment in the Citrus embryo. 

At the 30-60 celled globular stage of embryogenesis 

in the rough lemon (Citrus jambhiri), a central core 

of cells dividing in random planes is surrounded by 

cells whose anticlinal walls predominantly radiate 

out from the core. Not until a globular stage con- 

taining 150-200 cells, however, are periclinal divi- 

sions in the peripheral cells eliminated. Thereafter 

the convoluted surface becomes smooth as the proto- 

dermal cells are layered and tabular. The thick 

cuticle of the mature lemon epidermis is not obser- 

vable during embryogenesis under conventional histo- 

logical stains. Whether the layering of the surface 

cells is truly a reflection of commitment to epider- 

mal ontogeny is one subject of our investigations. 

Our experimental evidence to date indicates that 

once the epidermis is determined, except for rare or 

specialized circumstances, the subepidermal tissue 

lacks the competence to redifferentiate as epidermal 

even if put in the position and environment of an 

epidermal cell. Removal of epidermal cells in 

various organs (stems, leaves, floral organs) at 

various developmental stages has resulted in a 

replacement of the epidermis with wound callus or 

periderm rather than epidermal regeneration by sub- 

epidermal tissue. To test if embryos at sufficient- 

ly early stages of tissue commitment can be induced 

to regenerate a protoderm from subsurface cells, we 

have surgically removed the protoderm from intact 

embryos. Surgical procedures and subsequent growth 

of embryos required the development of an in vitro 

culture system where the lemon embryos were grown 

in nurse ovules of citron (Citrus medica). 

BUNTMAN, D.J.* and H.T. HORNER. Department of 

Botany, Iowa State University, Ames, IA 50011. 

- Microsporogenesis of normal and ms3 mutant soybean 

(Glycine max). 

The Ms3 genetic male sterile soybean anther is compared 

with its normal line by using light, scanning, 

and transmission electron microscopy. Floral development, 

with the exception of androecium development, 

is similar between normal and ms3 lines. The first 

difference between normal and ms anther development 

is observed in the tapetum. At Lhe early meiocyte 

stage ms mitochondria appear abnormal. The ms 

tapetum then becomes more disorganized and breais 

down prematurely. Tetrads are not released and subsequently 

abort. These events are accompanied by the 

accumulation of large amounts of an unidentified 

refractive material interior to the parietal cells. 

CALVIN,* CLYDE L. and M. CAROL ALOSI. Department 

of Biology, Portland State University, Portland, 

OR 97207 and Department of Botany, University of 

Cal iforni a, Berkel ey, CA 94720 - Devel opmental 


anatomy of thd epidermis of the dwarf mistletoe, 

Arceuthobium tsugense. 

The developmental anatomy of the epidermis of 

Arceuthobium tsugense (Rosendahl) G.N. Jones was 

studied using both light and scanning electron 

microscopy. Aerial shoots of the dwarf mistletoe may 

reach a height of 10 cm or more, but most are 

somewhat shorter. In recently emerged shoots the 

decussately arranged leaves of adjacent nodes overlap, 

concealing the stem. As internodal elongation 

continues, stem segments gradually become visible. 

The leaf pairs, which are joined at their bases, stop 

their development early. In mature stems they appear 

as small boat-shaped structures surrounding the nodes. 

No trichomes were present on the shoots examined at 

any stage of development. Stomates are present on 

stems and leaves. On the latter, they are most 

abundant on the keeled midregions of abaxial leaf 

surfaces. The longitudinal axes of stomates are 

oriented perpendicular to the stem,axis. Guard cells 

are partially covered by over-aching subsidiary cells, 

producing a small antechamber just above the stomatal 

aperture. Substomatal chambers are small to absent 

and contiguous tissues have a paucity of intercellular 

spaces. As development continues, the epidermis is 

covered by a very thick cuticular layer and stomates 

becomes occluded. Subsequently, subepidermal cells 

also secrete cuticular material, isolating sections 

of epidermal tissue that become necrotic. The changes 

outline constitute the formation of a cuticular 

epithelium much like that described for Phoradendron. 

The generally xerophytic features displayed by 

Arceuthobium seem inconsistent with known physiology 

of the parasite. 

P.C. CHENG*, TAN K.H., McGOWAN J.Wm. and FEDER R. 

Dept. of Anatomy, Univ. of Illinois, Chicago, IL; 

Canadian Synchrotron Radiation Facility(CSRF), 

Physical Sci. Lab., Univ. of Wisconsin, WI; Dept. 

of Physics, Univ. of Western Ontario, Canada; IBM 

T.J. Watson Res. Ctr., NY.-Recent developments in 

soft x-ray spectroscopy and contact microscopy. 

Feder et al(1981) reported that the x-ray image of 

blood platelets is different from the electron image, 

which they believe is due to differences in the x-ray 

absorption and electron scattering properties of P in 

cytoplasmic phosphate compounds. We have also reported 

some preliminary attemps on imaging plant tissues by 

x-rays. A better understanding of the absorption 

spectra of various biological compounds is important 

for future interpretation of x-ray microscopic images. 

Due to the availbility of a synchrotron source, only 

low(20-280 eV) x-ray spectra were used in this study. 

Three biological samples, ADP(Na salt), 1-methionine 

and crude corn leaf extract(1:1 methanol/chloroform) 

and two polyamino acids(homopolymers), poly-l-methio- 

nine and poly-cysteine, were used in the study. The 

samples were either dissolved in water or EtOH and 

coated on a thin Formvar film, or incorporated in the 

Formvar film(i.e. leaf extract). Absorption measure- 

ment was done on a beam line of Tantalus storage ring 

with a Mark IV Grasshopper monochromator(CSRF). The 

results show a P L absorption edge in the ADP sample 

and a S L edge in the 1-methionine, poly,l-methionine 

and poly-cysteine samples. The S L absorption edge of 

methionine shows a few eV shift from the atomic state. 

Corn leaf extract shows a P edge which could be 

contributed by membrane phospholipids. 

X-ray contact microscopy of various corn tissues were 

conducted with synchrotron radiation and x-rays 

generated by a stationary target source(C and V 

targets). X-ray contact images were formed on a PMMA 

x-ray resist back supported by a Si3N4 window, then 

the contact image magnif ied by a TEM.


* 

CONTRERAS, LUZ., and NELS R. LERSTEN. Depart- 

ment of Botany, Iowa State University, Ames, IA 

50011. 

-Foliar nectaries in Ebenaceae: Morphology, 

anatomy, and distribution. 

The Ebenaceae is variously interpreted as having 2-6 

genera. The approximately 450 species are trees or 

shrubs of mostly tropical distribution, although a 

few extend to temperate regions. Foliar nectaries 

are widespread in the family but they have mostly 

been reported as "glands" without any detailed de- 

scriptions. A morphological survey was made, largely 

from herbarium specimens, of about 160 species from 

the four major genera and most sections of Diospyros, 

the largest genus. One or more leaves from all 

species examined were cleared. Nectary-bearing 

portions of leaves from about 25 representative 

species were then processed for paraffin sectioning, 

and samples from a few living plants were processed 

for paraffin and resin sectioning, and for scanning 

electron microscopy. Foliar nectaries were found on 

all species except for a few in Euclea. There may be 

few to many nectaries per leaf. They are all abaxial, 

occurring both in the proximal and distal halves. 

All nectaries are discoid or oval and embedded, 

usually flush with the surface, but they can be 

divided into two categories. The A-type is small 

and lacks direct connections to vascular bundles, 

which remain separated by 2-3 layers of parenchyma 

sheath. A-type occurs mostly in North American and 

Asian species. B-type nectaries are mainly larger, 

with connections to veins which end just below the 

nec.tatiferotis tissue. B-type nectaries occur mostly 

in species from Africa and Central and South 

America. Nectariferous tissue in both consists of 

small, more-or-less isodiametric cells. Both types 

secrete abundant nectar containing fructose, glucose, 

maltose, and sucrose in about equal proportions. 

COOK, ROBERT EDWARD Population Biology/Physiol- 

ogical Ecology, NSF, Washington, D.C. 20550 

- Ideal and teal growth in Mediola. 

Recent theoretical and field studies of clonal growth 

and reproduction in herbaceous plants have emphasized 

the importance of "rules of growth" controlling mod- 

ular proliferation and generating geometric patterns 

of space occupation. Mediola virginiana is a clonal 

herb whose rhizomatous pattern of growth theoretically 

tesselates the space of the forest floor. In the 

study reported here, the real patterns of growth are 

analysed from a 3 x 4 meter map of a Mediola popula- 

tion. The "rules of growth" of Mediola rhizomes are 

much more variable than previously recognized and the 

occupation of space is stochastic in nature. Com- 

parison of the real patterns with the ideal geomet- 

ries of theory reveals significant aggregation in 

populations, and the adaptive benefits of tesselation 

are questioned. 

CURTIS, JOHN D. Biology Department, University 

of Wisconsin-SP, Stevens Point, WI 54481. 

Hydathode anatomy in marsh clinquefoil (Potentilla 

palustris RosaceaeT. 

Guttating leaves of Potentilla palustris were 

coll1ected i n Bayfi el d Co ., Wi sconsi n, and processed 

for thick plastic sections, clearings and scanning 

el ectron mi croscopy. Each attenuated leaf tooth 

is terminated by an elongated pad of 50 to 60 sunken 

water pores which are positioned directly above the 

terminus of two or usual ly three l arge vascul ar 

bundles. On fully enlarged leaves, the water pore 

guard cells are the same size as those of normal 

abaxial stomates and the pore is usually open. The 

rest of the hydathode epidermal pad is composed 

primarily of protoxylem and seem to lack a well 

defined bundle sheath. Epithem cells have few 

chloroplasts and few if any intercellular spaces. 

DEMASON, DARLEEN A.* and PAM1ELA K. DIGGLE. Botany 

and Plant Sciences, University of California, 

Riverside, 92521. - Histochemical and autoradiographic 

analysis of the relationship of the PTM 

and the STM in Yucca whipplei. 

Observations were made of RNA and protein-staining 

on plants ranging from embryos to three-month-old 

plants of Yucca whipplei Torr. var. percursa Haines. 

One-, two-, and three-month-old plants were labelled 

with tritiated thymidine, fixed in FAA, sectioned, 

stained with the Feulgen reaction, and prepared for 

autoradiography. The serial transverse sections 

were outlined with a camera lucida recording all 

labelled nuclei on a graphics tablet. Computerassisted 

reconstructions were made in three dimensions 

to observe the locations of labelled nuclei. 

The two techniques collaborate each other. The 

PTM is broad near the top of the stem and occupies 

narrower bands at successively basipetal levels of 

the stem, and finally disappears below the level 

of recent root initiation. There are no gaps in 

staining or labelling, and there are no changes in 

staining or labelling that would distinguish between 

activities of the PTM and the STM. They are 

continuous at all stages of development in the 

young vegetative stem. The STM is interpreted as 

a developmental continuation of the PTM. 

DENGLER, NANCY G. Department of Botany, University 

of Toronto, Toronto, Ontario M5S lAl. - Comparison 

of leaf development in normal (+/+), entire (e/e) 

and lanceolate (La/+) plants of tomato, 

Lycopersicon esculentum cv. Ailsa Craig 

The developmental processes which result in the 

morphological and histological differences between 

the compound leaves of normal (+/+) Lycopersicon 

esculentum and those of the mutants entire (e/e) and 

lanceolate (La/+) are described. Despite considerable 

differences in mature leaf size and form, dimensions 

of the shoot apical meristem, arrangement of young 

leaves in the bud and pattern of leaf expansion are 

similar in the three genotypes. In normal leaves 

lateral leaflet formation begins earlier and is of 

longer duration, resulting in a greater number of 

leaflet pairs. In the entire genotype growth of the 

lamina of the terminal leaflet is initiated earlier 

and expansion proceeds at a greater rate than in 

normal leaves. In lanceolate leaves lateral leaflets 

are usually absent and, while the lamina is initiated 

at the same stage as in entire leaves, extension 

occurs more slowly than in either of the other two 

genotypes, resulting in a narrow leaf blade. 

Detectable cell enlargement in the adaxial protoderm 

begins earlier and proceeds at a great rate in 

lanceolate leaves, resulting in greater cell area at 

maturity. 

DENGLER, RONALD E. , NANCY G. DENGLER and 

2PAUL W. HATTERSLEY. 'Department of Botany, 

University of Toronto, Toronto, Ontario M5S lAl, 

'-Research School of Biological Sciences, The

Australian National University, Canberra, A.C.T. 

2601. - Differing ontogenetic origin of PCR 

("Kranz") sheaths in leaf blades of C, grasses 

(Poaceae) 

The origin and development of ground meristem and 

provascular tissue have been examined in leaf blades 

of eight C4 grasses, representing different taxonomic 

groups and the three recognized biochemical C4 types 

(NADP-ME, NAD-ME and PCK types). Comparisons were 

made with the C3 species, Festuca arundinacea (pooid). 

In NAD-ME (Panicum effusum, eupanicoid; Eleusine 

coracana, chloridoid) and PCK (Sporobolus elongatus, 

chloridoid) species, the provascular tissue of 

primary veins gives rise to xylem, phloem and a 

mestome sheath; associated ground meristem differ- 

entiates as PCA ("C4 mesophyll") and the PCR ("Kranz") 

sheath. This parallels development in the C3 grass, 

except that associated ground meristem differentiates 

into mesophyll and a parenchymatous bundle sheath. 

By contrast, the provascular tissue of NADP-ME C4 

species (Panicum bulbosum and Digitaria brownii, eu- 

panicoid; Cymbopogon exaltatus, andropogonoid) 

differentiates into xylem, phloem and a PCR sheath; 

associated ground meristem giving rise only to PCA 

tissue. Findings support W.V. Brown's hypothesis 

that the PCR sheaths of NAD-ME and PCK-type C4 grasses 

are homologous with the parenchymatous bundle sheaths 

of C grasses, whereas in NAD-ME C4 grasses, they are 

homologous with mestome sheaths. Aristida 

biglandulosa and Arundinella nepalensis have unusual 

C4leaf anatomy of special interest to this hypo- 

thesis. 

DERSTINE, KITTIE S.* and SHIRLEY C. TUCKER. 

Department of Botany, Louisiana State University, 

Baton Rouge, LA 70803 

-Comparative floral ontogeny of Parkinsonia 

aculeata (Caesalpinioideae), Lupinus havardii 

(Papilionoideae) and Acacia baileyana (Mimos- 

oideae). 

The three subfamilies of Fabaceae are distinguished 

on the basis of floral symmetry, aestivation of 

petals in bud (valvate or imbricate), degree of 

fusion in calyx and corolla, and morphology of seeds 

and leaves. The first three characteristics will be 

addressed, using SEM primarily. Ontogenetic studies 

of a representative taxon in each subfamily are 

intended to determine when during development these 

diagnostic features first become evident. In each 

taxon, order of initiation of sepals and petals is 

used to establish first evidence of symmetry. Middle 

developmental stages elucidate first indications of 

aestivation and/or apparent fusion among sepals, 

petals and filaments. Final flower form is seen in 

later developmental stages with petal expansion into 

divergent forms and cell differentiation as well as 

degree of filament fusion and further apparant petal 

fusion. 

DICKISON, WILLIAM C. Department of Biology, 

University of North Carolina, Chapel Hill, NC 

27514. - Fruits and seeds of the Cunoniaceae. 

Cunoniaceae fruit morphology varies from ventrally 

dehiscent follicles, and dry, septicidally dehiscent 

capsules, to dry, indehiscent capsules, fleshy 

drupes, berries, and winged fruit types. The fol- 

licular fruit is the primitive condition in the 

family from which dehiscent capsules and indehiscent 

forms evolved. The majority of species produce 

fruit in which the pericarp is differentiated into 

exocarp, mesocarp, and lignified, fibrous endocarp. 


Major shifts ih dispersal strategy resulted in more 

advanced taxa in which the entire fruit is modified 

for seed dispersal and protection. Most dehiscent- 

fruited genera produce seeds with dispersal append- 

ages in the form of wings or hairs. Hairs are 

generally apically comate, less commonly distributed 

in other patterns. Genera with indehiscent fruits 

possess a variety of seed morphologies but all are 

devoid of wings or hairs. Seed coats are exotegmic 

in construction, that is, the outer epidermis of 

the inner integument differentiates into the 

mechanical layer. Two distinct trends are recog- 

nized in seed coat structure: (1) reduction in seed 

coat thickness, including loss of a mechanical layer, 

and (2) amplification of the seed coat by secondary 

divisions of integumentary cells in the post- 

fertilization ovule. The diversity of seed surface 

patterns will be described and illustrated. 

DIGGLE, PAMELA K.* and DARLEEN A. DEMASON. Botany 

and Plant Sciences, University 

Riverside, 92521. - Developmental 

of California, 

relationship 

between the PTM and the STM in Yucca whipplei. 

Histological and anatomical observations were made 

on plants ranging from embryos to three-year-old 

plants of Yucca whipplei Torr. var. percursa Haines. 

Our objective was to determine the time and position 

of origin, ontogenetic relationship, and function 

of the primary thickening meristem (PTM) and the 

secondary thickening meristem (STM) during development 

of the vegetative axis. The PTM arises in 

the stem periphery during germination. It is longitudinally 

continuous from beneath the youngest 

leaf primordia to the primary root, and functions 

in the production of primary vascular bundles and 

ground tissue. The STM arises ontogenetically from 

the PTM in the base of two- to three-month seedlings 

and produces secondary vascular bundles and ground 

tissue. Parenchyma in the ground tissue is arranged 

in anticlinal cell files continuous from beneath the 

leaf bases, through the cortex and central cylinder 

to the pith. Individual vascular bundles in the 

primary body are collateral. The parenchyma cells 

of the ground tissue of the secondary body are also 

arranged in files continuous with those of the primary 

parenchyma. Secondary vascular bundles are 

amphivasal and have an undulating path with frequent 

anastomoses. The PTM and STM, primary and secondary 

vascular bundles, and files of primary and secondary 

ground tissue are continuous at all developmental 

stages studied. Development of the primary body is 

histologically and quantitatively similar to development 

in monocotyledons which possess only a PTI; 

and secondary growth is interpreted as a developmental 

continuation of the process of primary thickening. 

DUTE, ROLAND 

R. Department of Botany, Plant 

Pathology, and Microbiology, Auburn University, 

Auburn, AL 36849. 

- Features of sieve-element ontogeny in Ginkgo 

biloba. 

In an effort to enhance our knowledge of the phloem 

of gymnosperms, an ultrastructural investigation was 

conducted into the development of petiolar sieve 

elements of Ginkgo biloba. As in the sieve elements 

of other species, there is a stage of ER stacking 

which precedes cytoplasmic lysis. In some cases the 

ER forms concentric layers enclosing portions of 

ribosome-rich cytoplasm. These concentric layers are 

held together by bridges of 7 nm in length which


traverse the intercisternal spaces. In newly-matured 

sieve elements whose lumina are otherwise devoid of 

ribosomes, the concentric layers may retain ribosome- 

rich centers. 

During the process of lysis, those structures not 

destroyed become localized along the plasmalemma. 

The process of localization in Ginkgo is associated 

with attachment of organelles to bundles of micro- 

filaments. The peripheral position of structures in 

the mature sieve element is maintained by minute 

bridges observed between plasmalemma and ER, and by 

association between ER and mitochondria. 

Due to the overall similarity of sieve-element 

ontogeny in different vascular plants, it is hypo- 

tlhesized that similar structures and associations 

will be observed elsewhere. 

EL-GHAZALY, GAMAL AND WILLIAM A. JENSEN*. Botany 

Department, University of Alexandria, Egypt, and 

Botany Department, University of California, 

Berkeley, CA 94720. - Ontogeny of pollen wall of 

Triticum aestivum. 

Pollen of Triticum aestivum was studied at a series 

of developmental stages. Observations were made on 

the ultrastructural level and the light microscope 

level. Cytochemical tests were made to determine, 

where possible, the chemical nature of the developing 

wall. In the late tetrad a thin fibrillar matrix 

formed around each microspore between the callosic 

special cell envelope and the plasma membrane. 

Bacules are initiated as dense stained patches 

distributed in the fibrillar matrix. On release of 

the microspores from the tetrad the bacules are dif- 

ferentiated into a cylindrical rod with a conical 

head which extends beyond the distal surface of the 

fibrillar matrix. The fibrillar matrix is elevated 

from the plasma membrane and has a reticulate pat- 

tern. The tectum is formed as a result of deposition 

of material on the fibrillar matrix. The foot layer 

is established on both sides of a white line cen- 

tered lamellation formed on the surface of the plasma 

membrane of the free microspores. There are sites on 

both tectum and foot layer where material was not 

deposited and consequently channels in the exine are 

formed. The plasma membrane becomes undulated and a 

compact fibrillar layer which designates the endexine 

is formed on the plasma membrane distal surface. A 

thick intine, containing cytoplasmic strands, forms 

at the proximal surface of the endexine. Detailed 

analysis of the development of the aperture has been 

investigated. 

EVERT, RAY F., C.E.J. BOTHA and ROBERT J. 

MIERZWA*. Departments of Botany and Plant 

Pathology, University of Wisconsin, Madison, WI 

53706; Department of Botany, Fort Hare University, 

Republic of Ciskei, South Africa. - The use of 

free-space markers in the study of water movement 

in the leaf of Zea mays L. 

Two techniques were used for the study of water 

movement in the xylem and leaf apoplast of Zea mays, 

the Prussian blue technique and one utilizing lan- 

thanum nitrate. Prussian blue crystals and deposits 

of lanthanum were found within the lumina of the 

vessels and the apoplast, or cell wall continuum, 

of the vascular tissutes and bundle-sheath cells. 

Although numerous Prussian blue crystals and 

lanthanum deposits were found in the outer tangential 

and radial walls of the bundle-sheath cells, few or 

none were found in the walls of mesophyll cells 

contiguous to the bundle sheath. This pattern of 

deposition indicates that the suberin lamellae in 

the outer trangential walls of the bundle-sheath 

cells effectively inhibited the apoplastic movement 

of water between the bundle sheath-mesophyll cell 

interface. 

EVERT, RAY F.*, WALTER ESCHRICH and ROBERT J. 

MIERZWA. Departments of Botany and Plant Pathology 

University of Wisconsin, Madison, WI 53706; 

Forstbotanisches Institut der Universitgt 

Gottingen, Bu'sgenweg 2, D3400 Gottingen, Federal 

Republic of Germany. - Cytochemical localization 

of ATPase activity in the leaf of Zea mays L. 

Standard lead precipitation procedures were used to 

study the localization of ATPase activity in the 

mature leaf of Zea mays. ATPase activity was most 

consistently localized on the outer surface of the 

plasmalemma of the vascular parenchyma cells contigous 

to both vessels and thick-walled sieve tubes. 

(The thick-walled sieve tubes typically have 

numerous pore-plasmodesma connections with the 

vascular parenchyma cells.) The plasmalemma of the 

thick-walled sieve tubes exhibited relatively light 

deposits of reaction product. By contrast, in the 

same vascular bundles, the plasmalemmas of the thinwalled 

sieve tubes commonly contained very heavy 

deposits on both their surfaces. Reaction product 

also was associated with the sparse, parietal endoplasmic 

reticulum of the thin-walled sieve tubes. 

The plasmalemmas of the companion cells often contained 

less enzyme activity than those of their 

associated thin-walled sieve tubes. The plasmalemmas 

of the bundle-sheath cells and mesophyll cells often 

contained little or no reaction product. Little or no 

enzyme activity could be detected in association with 

the plasmodesmata between the various cell types. 

Together with previously obtained information on the 

maize leaf, the results of this study indicate that 

the plasmalemma of vascular parenchyma cells, 

companion cells, and thin-walled sieve tubes are involved 

in the active transport of sucrose into these 

cells, while little active transport occurs across 

the plasmalemma of the thick-walled sieve tubes. 

EWERS, FRANK W.* and MARTIN H. ZIMMERMANN. 

Har- 

vard University, Harvard Forest, Petersham, MA 01366 

- The hydraulic architecture of two conifers. 

Trees of Abies balsamea and Tsuga canadensis were 

studied to determine from both a structural and func- 

tional point of view how well these species conform to 

the "pipe model" theory, where the plant is regardedas 

an assemblage of "unit pipe systems", each of which 

support a unit of leaves. This model predicts a con- 

stant Huber value (cross-sectional xylem area per dry 

weight of supplied leaves) throughout the plant. 

However, in both species the Huber value rose sharply 

in going up the tree, e.g., for a 5 m tall tree of 

Abies from .035 at the base to 11.6 cm2/g near the tip. 

In terms of water conduction, measurements of leaf- 

specific conductivity (LSC-conductivity in gl per hour 

at gravity gradient divided by dry weight of supplied 

leaves) are more informative than Huber values. LSC's 

decreased in going up the plant in the above tree from 

277 at the base to 96 near the tip. The greater LSC 

values toward the base are apparently due to larger 

tracheids (X= 41 gm diameter at base vs. 18 gm near tip). 

Superimposed on the above trends the trunk portions 

had greater LSC and Huber values than branches of com- 

parable diameter . The dif ferences between trunks and 

branches were much greater in Abies balsamea than in

Tsuga canadensis, which may be a reflection of .the 

stronger apical dominance in the former species. The 

pipe model would have to be modified to account for 

the above data, such that each unit pipe system had 

many more but smaller tracheids near the top than the 

bottom of the tree, and such that the trunk component 

of a unit pipe had more and wider tracheids than the 

lateral branch component. A more useful morphogenetic 

model involves hormonal gradients that control tracheid 

size and number in the plant. Hydraulically the ar- 

chitecture of these species favors the trunk over 

lateral branches and may thus help the upper leaves on 

the tree to compete with lower leaves for water and 

minerals. 

FAGERBERG, WAYNE, R. Dept. of Biology, 

Southern Methodist University, Dallas, TX 

75275.- A morphometric analysis of the 

homogeneity of palisade cell structure in 

leaves of Helianthus annuus. L. 

Leaves were divided into four quadrants and 

random samples taken from each quadrant. 

The ratio descriptors, Vv and Sv were cal- 

culated to describe the relationship between 

organelle compartment and cell size for the 

chloroplast, mitochondria, vacuole, micro- 

body, oil, starch, and mitochondrial - 

chloroplast membrane compartments. Since 

ratio values do not often reflect changes 

in mean cell volume, cell volumes and actual 

compartment sizes were also determined. In 

mature fully expanded leaves statistically 

significant variations were found between 

quadrants in Vv ratio of the chloroplast, 

vacuolar and starch compartments and in the 

Sv ratios of the granal membranes. The 

granal membrane compartment was the most 

variable, between sampled quadrants. The 

starch compartment was significantly smaller 

in the bottom 1/2 of the leaf suggesting 

that starch may be more rapidly mobilized 

from the lower half of the leaf. This study 

suggests that palisade cells are not homo- 

genous throughout the whole leaf due to 

variation in organelle compartments involved 

with photosynthesis. These results will be 

compared to similar data derived from 

developing leaves. 

FIORES, EUGENIA M. Escuela de Biologia, Univer- 

sidad de Costa Rica, San Josg, Costa Rica, Amgrica 

Central. - Cauline glands of Gunnera insignis. 

Cauline glands of Gunnera insignis were studied with 

light and scanning electron microscopy. Two types 

are recognized: (1) stellate glandular trichomes 

secreting mucous material and (2) whitish lobulated 

bodies covered by stomata which release water. The 

glandular trichomes develop around the leaf 

primordia and between the numerous squamules. These 

organs, as well as the shoot apex, are immersed in 

the mucous secretion. Many filaments of Nostoc and 

other organisms (algae, fungi, nematodes, insect 

larvae) are observed living in the mucilage. Nostoc 

is also recognized inside the trichomes and cauline 

tissues. Eventually, these trichormes degenerate and 

form brownish spots associated with Nostoc. The 

structures wich release water develop later and 

occupy the spaces left by the glandular trichomes. 

They cease functioning, turn green and extend 

longitudinally when the leaf~ which they surround 


reaches maturity. The interaction Gunnera - Nostoc 

represents the only known symbiosis between an 

angiosperm and a nitrogen-fixing bluegreen alga. 

This relationship is still not well known. 

Apparently in Gunnera the alga Nostoc penetrates 

through the glandular trichomes. It seems pertinent 

to study the role of these glands in relation with 

Nostoc penetration and the nitrogen fixing mechanism. 

FOLSOM, MICHAEL W. Dept of Botany, Univ. of Alberta, 

Edmonton, Alberta, CANADA T6G 2E9. -Structural aspects of the 

central cell gf Soybean. Glycine max (L) Merr. with respect to 

fixation technique. 

Ultrastructure of the eight nucleate embryo sac of soybean Glycine 

max (L.) Merr. demonstrates an unusual sequence of events in the 

central cell. Metabolites enter the embryo sac, are polymerized into 

starch grains, and are degraded mostly disdppearing from the 

central cell before fertilization. These starch grains are organized 

into groups that have been referred to as "packets" by previous 

workers. Unlike starch grains reported in most plant cells these 

packets do not appear to be membrane bound. The absence of a 

membrane is most likely not caused by fixation problems since 

other membrane bound organelles of the central cell exhibit normal 

membranes. The addition of Alcian Blue 8GX (AB) to the fixation 

process shows that rather than being naked or bound by a plastid 

membrane, these paskets are at least partially enclosed in a layer of 

amorphous material, a mucopolysaccharide, deposited some time 

after the starch grains begin to form. Coomassie Brilliant Blue has 

shown that the material surrounding the starch packets has a protein 

component. The role of Alcian Blue acting as stabilizing agent for 

this glycoprotein and the preservation of cellular components by 

various fixation techniques (e.g. GA/Os04, GA + AB/Os04, 

GA/OsOi/TA/OsO4, and freeze substitution) will be discussed with 

respect to the starch packets and associated glycoprotein in the 

central cell. 

FREEMAN, THOMAS P., MURRAY E. DUYSEN AND 

THOMAS J. GULYA. Departments of Botany and 

Plant Pathology, North Dakota State 

University and U.S.D.A. Agricultural 

Research Service, Fargo, N.D. 58105. 

chloroplasts caused by Pseudomonas 

syringae pv. ta etis. 

Severe chlorosis and ultrastructural modifi- 

cations of chloroplasts occur in sunflowers 

in response to infections of Pseudomonas 

syringae pv. tagetis. Chlorosis became 

apparent within two days after the cotyledons 

of ten day old sunflower seedlings were 

inoculated with the bacteria. The first 

symptoms gererally appeared in the center of 

leaves at the second node above the cotyle- 

dons. During the rext few days the chlorosis 

progressed to include leaves at several 

nodes. Despite the fact that some of these 

leaves lost essentially alL of their pigmen- 

tation they remained turgid and continued to 

expand. The loss of pigmentation is 

directly related to ultrastructural changes 

within the chloroplast. Grana thylakoids 

became dilated and separated from the granal 

stacks. These thylakoid membranes were not 

altered as in the cases of chromoplast 

formation or normal senescence. Both grana 

and stroms thylakoid membranes coalesced to 

form a large membrane sheet in the center of 

the plastid. Starch and plastid ribosomes 

were lost early in the chlorotic cycle. 

Other cellular organelles do not appear to be 

altered by the bacterial i nf ection .


FRENCH, J.C. Department of Biological Sciences, 

Mississippi State University, Mississippi State, 

MS 39762-5759. - Preliminary observations on the 

anatomy and systematic occurrence of secretory 

structures in Araceae. 

A preliminary survey was made of the structure and 

systematic occurrence of extrafloral nectaries, wax 

glands, resin canals and laticifers in Araceae. Extrafloral 

nectaries were found in only two subfamilies, 

Philodendroideae and Lasioideae; extrafloral nectaries 

from both taxa have a similar anatomical organization. 

Wax glands were found on the undersides of leaves at 

the juncture of certain primary veins and the midvein 

of several species of Alocasia and Xenophya. A wax 

gland comprises a palisade layer of epidermal cells 

that excretes a thick outer plaque of wax. Resin 

canals have been found in roots, stems and leaves of 

certain genera of Lasioideae and Philodendroideae. 

Resin canals in roots of Philodendron, Cercestis and 

Culcasia have a sclerenchyma sheath surrounding the 

epithelTum. Resin canals in some species of Culcasia 

lack both an epithelium and intercellular space, and 

have only sclerenchyma. Laticifers of Colocasioideae 

were found to contain a variety of particles in their 

latex, including osmiophilic bodies about 8 vm in 

length. Two types of these large particles have been 

found, one typical of latex from Old World genera, e.g. 

Colocasia, and a second type typical of New World 

genera, e.g. Syngonium. Laticifers from roots of 

Colocasioideae examined thus far differ from those in 

the shoot in lacking the large osmiophilic particles 

in latex, and in lacking anastomoses. 

FRENCH, J.C. and P.B. TOMLINSON. Department of 

Biological Sciences, Mississippi State University, 

Mississippi State, MS 39762-5759 and Harvard Forest, 

Petersham, MA 01766. - A summary comparison 

of vascular bundle organni-zation in Araceae, Cyclanthaceae 

and Pandanaceae. 

In previous, separate studies compound vascular bundles 

have been investigated in three families of monocotyledons: 

Araceae, Cyclanthaceae and Pandanaceae. 

These results are brought together in the form of a 

summary comparison. Compound bundles from different 

taxa may appear to have a similar construction when 

comparisons are based on single transverse stem sections. 

However, when the three-dimensional course of 

bundles is compared from representatives of Araceae, 

Cyclanthaceae, and Pandanaceae, distinctly different 

patterns of construction are found. These results 

confirm the usefulness of cinematographic methods in 

comparative studies of the anatomy of monocotyledons. 

The results also support the view that these families 

probably have no close phylogenetic affinity. In 

addition, the concept of the compound vascular bundle 

has been broadened to include: 1) forms which. intergrade 

with amphivasal bundles, a common feature of 

some Araceae, e.g. Dieffenbachia, Philodendron and 

2) bipolar or multipolar bundles resul`ting from longdelayed 

fusion between a leaf trace and axial bundle(s), 

which is a consistent feature of Cyclanthaceae. 

FRENCH, J.C. and P.B. TOMLINSON. Department of 

Biological Sciences, Mississippi State, MS 39762 

and Harvard Forest, Petersham, MA 01766. - 

Cinematic analysis of stem vasculature in Philodendron 

(Araceae. 

A survey of stem vasculature in Philodendron has been 

made using cinematic analysis of series of transverse 

secti ons . Phil1odendron exhi bi ts the most di verse 

vascular organiza~tion in the Araceae, with respect to 

both the arrangement of xylem and phloem in vascular 

bundles and the three-dimensional course of the bundles. 

In a few species (P. scandens) simple collateral 

bundles are present in the central cylinder, and when 

leaf traces are followed basipetally each trace fuses 

with an axial bundle. In other species bipolar,or 

tri- to multipolar bundles predominate in the central 

cylinder, and exhibit a complex pattern involving unpredictable 

fusion and/or anastomosis of components in 

compound bundles. In some species with compound bundles 

each collateral component is completely surrounded 

by a sclerenchyma sheath, while in other species little 

or no sclerenchyma is present, and compound bundles 

appear to intergrade with amphivasal bundles. In addition 

to intermediate types, well-defined amphivasal 

bundles are present in some species, which have a 

solid core of phloem and a continuous cylinder of xylem. 

In some species of Philodendron with amphivasal 

bundles some of the tracheary elements do not develop 

in a typical fashion. Even in mature stems secondary 

cell walls of some elements remain thin and unlignified 

or are absent, and cell diameters are reduced. 

When this condition occurs, it is typically found in 

many bundles in a stem, and has been found in 17 species 

(e.g., P. smithii, imbe, hastatum, longilaminatum) 

thus far. 

GRAYBOSCH, ROBERT A.* and PALMER, REID G. 

Genetics Department, Iowa State University, Ames, 

IA. 50011. 

- Cytological studies on a male-sterile mutant 

(ms2) in soybean (Glycine max). 

All known male-sterility mutations in soybeans are 

of the genetic type; to date, six such recessive 

nuclear mutations have been described. The ms2 

mutant was discovered in 1975, but no cytological 

studies aimed at elucidating exact causes of male 

sterility have been undertaken. This report presents 

results of preliminary studies on cytological events 

associated with the ms2 mutant, accomplished via 

comparative studies of anther and pollen development 

in male-sterile and male-fertile plants. Squash 

preparations reveal that chromosome pairing and segregation 

is normal in microspore mother cells of 

developing sterile anthers. Microsporogenesis proceeds 

normally until tetrad stage, at which time premature 

abortion usually occurs; on rare occasions 

separation of microspores from tetrads occurs, but 

release of microspores from callose was not observed. 

Abnormalities in the tapetal layer are associated with 

tetrad degeneration. These are manifested in the 

form of vacuoles or inclusions, first observed during 

first meiotic division of microspore mother cells. 

They progressively enlarge during anther ontogeny. 

Tapetal development resembles that occurring in 

plants homozygous for either the ms3 or msp (partial 

male sterile) mutations. Anther morphology is 

normal during early developmental stages, but a 

progressive degeneration of external tissues is 

noted. 

GRIMSON, MARK J.* and HOWARD J. ARNOTT, 


Arlington, Arlington, TX 76019-0498. - Electron 

microscopy of druse crystals in the abscission zone of 

Phyllanthus niruri L. 

Abscission plays an important role in the development and 

survival of plants. In Phyllanthus niruri L 

(Euph-orbiaceae), masses of druse crystals are found proxi- 

mal to the abscission zone of the leaf and flower as well as

in the septa between the carpels. Although crystal sand 

can be found in cells of the ovary and prismatic crystals in 

leaf idioblasts, only druses are found in the zones asso- 

ciated with abscission or dehiscence. The druses are found 

in the abscission zones at relatively early stages long 

before abscission is to occur. The druses (a multiple array 

of twin crystals arranged in a spherical space) develop 

within the vacuole of the crystal idioblasts. The druses 

vary somewhat in size and morphology and in the structure 

of the individual crystals which make up the druse. In 

some cases crystals are sharply pointed, in other cases they 

are less pointed or even rounded. As the crystals of the 

druse develop some appear to press through the cytoplasm 

and grow near the cell wall. Later in development a cell 

wall-like sheath grows around the crystal. Whether this is a 

response to the crystal penetrating the cytoplasm and 

appressing the cell wall is not yet clear. The cell wall-like 

sheath can easily be seen by electron microscopy and 

appears similar to the primary wall. Isolated crystals may 

still be encased by this sheath. Once the sheath is 

complete the crystal is sealed off from the remainder of 

the still living cell. After the organ has abscissed the 

crystal remains just below the scar left by abscission. The 

concentration of crystals at this point suggests a possible 

protective role for the crystals. Obviously this may be a 

secondary "function" in that the crystals may play a more 

meaningful role in calcium metabolism prior and during the 

formation of the abscission layer. 

JENSEN, WILLIAM A.*, MARIE MIZELLE, RAVINDER 

SETHI and MARY ASHTON. Department of Botany, 

University of California, Berkeley, CA 94720. 

- Pollen development in wheat treated with a 

chemical hybridizing agent. 

Triticum aestivum seedlings were treated with a 

chemical hybridizing agent developed by Rohm and Haas 

Chemical Company known as RHOO07. It caused the 

pollen to abort without markedly affecting the fer- 

tility of the ovule. Ultrastructural and histo- 

chemical studies revealed the compound specifically 

inhibited the formation of sporopollenin. This 

inhibition was not complete but the pollen in treated 

plants laid down a wall only 1/3 as thick as that 

found in the control. Histochemical studies indicate 

that it is not the synthesis of the carotene subunits 

but the polymerization step that is inhibited. 

JENSEN, WILLIAM A.*, MARIE MIZELLE, RAVINDER SETHI 

and MARY ASHTON. Department of Botany, University 

of California, Berkeley, CA 94720. - Ultrastructural 

study of pollen development in wheat. 

A study of pollen development in Triticum aestivum 

was made using the electron microscope. The study 

began with the microspore mother cell and continued 

to the mature pollen. Stress was placed on the 

changes in the cytoplasm during the various developmental 

stages, as well as oni the wall. Marked 

changes in ribosome number, plastid size and shape, 

and amounts of ER were noted at various stages. 

The quantity of wall deposited was also studied in 

detail. This study forms the foundation for the 

data presented in the subsequent work on a chemical 

hybridizing agent. 

KANE, MICHAEL E.* and LUKE S. ALBERT. Department 

of Botany, University of Rhode Island, 

02881. - Effects of ABA on-heterophylly 

Kingston, RI 

and stomatal 

development on submerged juvenile shoots of 

Myriophyllum heterophyllum Michx. 

In the heterophyllous aquatic angiosperm M. hetero- 


phyllum, submerged juvenile shoot apices develop dis- 

sected astomatous leaves that are composed of fili- 

form divisions consisting of a compact mesophyll. In 

contrast, aerial juvenile apices develop smaller and 

thickened pinnatisect leaves which bear adaxial sto- 

mata in a cutinized epidermis and lacunae within the 

mesophyll. Results of recent investigations on the 

physiological control of submerged and emergent forms 

in two other heterophyllous aquatics suggest a role 

for water-stress induced formation of abscisic acid 

(ABA) in the development of aerial leaf morphologies. 

To determine whether ABA also plays a role in the de- 

velopment of the aerial juvenile phase of M. hetero- 

phyllum, axenic cultures of the submerged juvenile 

phase were grown in a liquid medium consisting of 

Murashige and Skoog salts, vitamins, and 3% sucrose 

with or without ABA (10-9 to 10-4M) at 25 C in a 16 

hr photoperiod (PAR; 200 uE m-2s-l) for 10 days. Con- 

trol plants produced astomatous leaves typical of the 

submerged growth phase while exposutre to 10-6, 10-5, 

or 10-4 M ABA induced the formation of leaves morpho- 

logically and anatomically similar to those on aerial 

juvenile shoots. The influence of ABA on adaxial 

stomatal development was evident by observed increases 

in stomatal densities with hormone concentration (23, 

100, 150, and 154 stomates/mm2 for plants exposed to 

10-7, 10-6, 10-5 and 10-4 M ABA, respectively.) The 

hormone ABA therefore appears to play an important 

role in the control of heterophylly and stomatal 

development in an increasing number of aquatic 

angiosperms. 

KAUL, ROBERT B. School of Life Sciences, 

University of Nebraska, Lincoln NE 68588. 

-Inflorescence architecture and evolution in 

Asiatic Fagaceae. 

More than 200 Far Eastern species of Castanea, 

Castanopsis, Lithocarpus, and Quercus have been 

examined. Flowers are borne on spikes that are 

axillary to leaves and bracts of the current and 

previous seasons' stems. The spikes are often 

unisexual and male spikes greatly outnumber females 

on a tree. Some spikes, however, are androgynous, 

gynecandrous, or androgynecandrous, and all three 

conditions can occur on a single tree. Various 

degrees of separation of the sexes and of aggrega- 

tion of spikes into reproductive short-shoots exist. 

Some short-shoots have abortive apices and others 

produce monopodial continuation growth. Sometimes 

both kinds occur on the same individual, in which 

cases the determinate short-shoots are below the 

indeterminates and ordinarily bear only male flowers; 

the determinates usually bear a few female flowers 

in their distal spikes. More or less paralleling 

these phenomena is reduction from foliage leaves to 

bracteoles on the short-shoots. The most extreme 

condition occurs in Quercus, where the short-shoots 

are always unisexual, determinate, and only bract- 

eolate, and male flowers are borne on pendulous 

spikes (catkins). 

KAUSCH, A.P.* and H.T. HORNER. Department of 


- Increased nuclear DNA content during raphide 

crystal idioblast development in Vanilla plani- 

folia L. 

Files of calcium oxalate raphide crystal idioblasts 

are formed in the cortex of adventitious roots of 

Vanilla planifolia L. Idioblast initials are first 

recognized by intense fluorescence of the cytoplasm 

with the acridine orange method. Nuclear and nucleo-


lar enlargement ensue and continue during development; 

these cells do not undergo mitosis. Two-wavelength 

Feulgen microspectrophotometry was accomplished on 

root cortical preparations to determine the DNA 

content of idioblast nuclei during their development. 

Telophase nuclei (measured individually) and anaphase 

nuclei (measured together) served as internal 

standards (2C:4C) for relative DNA content of corti- 

cal parenchyma cells. Chicken erythrocytes were used 

as an internal quantitative standard (2.62 pg DNA/ 

nucleus). DNA content of developing crystal idio- 

blasts averaged 5.9 times that of telophase cortical 

parenchyma cells and ranged from 4C to 32C. Light 

and electron microscopy provides structural evidence 

of polyteny in idioblast nuclei. Heterochromatic 

regions are larger and slightly more numerous com- 

pared to interphase nuclei of cortical parenchyma 

cells. Frequency distribution of idioblast DNA 

contents indicates endopolyploidy, probably via 

endoreduplication, to an octaploid condition followed 

by less strict DNA replication within the idioblast 

genome. 

LERSTEN, NELS R.*, AND GLENN W. TURNER. Depart- 

ment of Botany, Iowa State University, Ames, IA 

50011. 

- Foliar nectaries in Ardisia (Myrsinaceae). 

Ardisia is the largest genus of the Myrsinaceae (35 

genera, 1000 species), with about 400 species of 

mostly tropical shrubs and small trees. We investi- 

gated the anatomy of extrafloral nectaries that occur 

on the leaves of some species using light and scan- 

ning electron microscopy. We also studied the dis- 

tribution of these nectaries with a dissecting micro- 

scope on herbarium specimens of 60 species repre- 

senting 13 of the 14 subgenera usually recognized. 

This is the first report on the occurrence and 

structure of an extrafloral nectary for any member 

of the Order Primulales. Nectary structure varies 

from isolated, short, capitate trichomes to large 

discs with a palisade epidermis on a broad base of 

large isodiametric cells. Both types are sunken in 

epidermal depressions, so that in each the upper 

surface of the nectary is nearly flush with the sur- 

rounding epidermis. Copious nectar secretion was 

observed from large nectaries on greenhouse grown 

plants of A. polycephala and small amounts from the 

capitate trichomes of A. crenata. Intermediate 

forms were observed on herbarium material and the 

two types appear to be homologous. Ardisia extra- 

floral nectaries fit into Zimmerman's (1932) cate- 

gory of Schuppennektarien ('scalelike nectaries'). 

Such nectaries have been reported to be derived from' 

trichomes in certain other groups of plants. 

Nectary distribution in Ardisia correlates somewhat 

with geography and this may be of some use as a 

taxonomic character. 

MACDONALD, JOANNE E. Department of Forest Resources, 

University of New Brunswick, Fredericton, 

N.B., Canada, E3B 6C2. 

- Effect of date of cut on length, winterreadiness 

and winter-survival of first-year stump 

sprouts of sugar maple (Acer saccharum Marsh.). 

The study was conducted on a cl earcut area of the 

Nashwaak Experimental Watershed Project in the west 

central uplands of New Brunswick, Canada. Thirty 

residual trees (6 to 10 cm dbh) were cut during the 

overwi nteri ng dormant peri od and the subsequent 

growi ng peri od . El ongati on of domi nant and co- 

dominant sprouts on stumps of these trees was moni- 

tored weekly during the subsequent or the remaining 

part of the growing period. Sprouts were examined 

in late October for indications of winter-readiness, 

and in the following June to assess winter-survival. 

Vigour of elongation, sprout length, and degree of 

winter-readiness decreased with each successive date 

of cut. In late October, most leaves had abscised 

and most internodes were woody on sprouts arising 

from dormant-period cuts. Leaves were brown and 

rigid on sprouts arising from June and early July 

cuts, and straw-coloured and limp on sprouts arising 

from late July cuts. The proportion of hardened in- 

ternodes decreased with each successive date of cut 

on sprouts arising from June and July cuts. Frost 

damaged distal leaves and internodes on sprouts 

arising from late July cuts, and all leaves and in- 

ternodes on sprouts arising from August cuts. Dam- 

age ranged from isolated black blotches on tissue to 

fully blackened, hardened tissue. In June, after 

overwintering, terminal buds and distal and proximal 

lateral buds burst on some sprouts, and only distal 

and proximal lateral buds burst on bther sprouts 

arising from dormant-period and June cuts. Only 

proximal lateral buds burst on sprouts arising from 

July cuts. Sprouts arising from August cuts did not 

survive the winter. 

MACDONALD, S. ELLEN*, DAVID M. REID and C.C. 

CHINNAPPA. Department of Biology, University 

of Calgary, Calgary, Alberta, Canada. T2N 1N4 

- Studies on phenotypic plasticity in the 

Stellaria longi pes complex (Caryophyllaceae): 

Stem elongation. 

The Stellaria 1ongipes complex is known to be a 

plastic group with respect to: number of flowers, 

length of stem, leaf shape, pigmentation and 

cuticular wax. It has been shown that thermoperiod 

has a greater effect than photoperiod in inducing 

stem elongation. Stem elongation and subsequent 

flowering are further investigated here. Evidence 

is presented for a winter cold requirement to 

achieve maximum stem elongation and for flowering. 

A cumulative temperature effect operates in inducing 

stem elongation, while light appears to have a 

synergistic effect. Temperature is shown to 

override the effect of hormones (GA and AbA) on 

stem elongation. Induction of stem elongation 

in response to red:far red ratio will be discussed. 

MAHLBERG, 

PAUL G. , AND JOANNA PLESZCZYNSKA. 

Department of Biology, Indiana University, 

Bloomington, IN. 47405. - Evolution of succulent 

Euphorbia as interpreted from latex composition. 

The morphology of starch grains and the gas-liquid 

chromatographic profile of triterpenes derived from 

latex of the nonarticulated laticifer of succulent 

African Euphorbia were examined for their 

applicability to interpret phylogenetic 

relationships of this genus. Several trends in 

starch grain morphology and triterpene composition 

were evident in the 38 examined taxa. Rod shaped 

grains, interpreted to be conservative, occurred in 

only a few taxa in several dwarf groups. Grains of 

osteoid shape prevailed in most taxa. Highly 

osteoid grains possessing lobed ends represented 

the most complex form and were present in some taxa 

endemic to Madagascar. Triterpene profiles which 

contained from 2 to 14 or more compounds were 

derived from all taxa. Each taxon possessed a

characteristic profile, or identifying fingerprint. 

The composition of the profile differed 

quantitatively and qualitatively among taxa. Taxa 

with few triterpenes, tentatively interpreted as 

primitive, occurred in dwarf forms, whereas 

Madagascan taxa tended to possess high numbers of 

triterpenes reflective of specialization. This 

study supports the interpretation that laticifer 

starch grain morphology and triterpene composition, 

both gene mediated stable markers, can be employed 

to determine and correlate phylogenetic 

relationships between taxa of this complex genus. 

MAKSYMOWYCH, ROMAN* Department of Biology 

Villanova University, Villanova, PA 19085 

MYRON C. LEDBETTER, Biology Department, 

Brookhaven National Laboratory, Upton, 

NY 11973. 

- Fine Structure of Secretory Canals 

in Xanthium pennsylvanicum Petioles. 

Secretory canals, lined with an epithelium, 

occur in many families, e.g. Umbelliferae, 

Compositae. These canals extend continu- 

ously through the root and shoot systems and 

are known, in some cases, to secrete resins, 

essential oils, etc. In Xanthium the canals 

initials. Subsequent divisions lead to a 

ring of 7-12 epithelial cells surrounding a 

central cavity. During maturation the 

epithelium becomes crushed and obliterated. 

Canals were examined in petioles of Xanthium 

pennsylvanicum (Cocklebur) plants grown 

under long day illumination to maintain 

vegetative growth. The fine structure of 

the canal and its epithelium was studied by 

electron microscopy of thin sections cut 

transverse to the principal axis of petioles 

from leaves in an early stage of develop- 

ment. The canal proper is delimited by 

walls of epithelial cells which protrude 

into a scallop shaped cavity. In comparison 

to the surrounding parenchyma, the epith- 

elial cells are smaller, cytoplasmically 

more dense, and less vacuolate. The epith- 

elium contains pleomorphic starch-free 

plastids with planar thylakoids frequently 

stacked into granna; thus, the plastids are 

presumed photosynthetically active. 

Mitochondria are abundant and often dense. 

The cytoplasm is rich in free polysomes, and 

smooth endoplasmic reticulum predominates 

LELAND C. MARSH AND JAMES L. SEAGO, JR.*. Department 

of Biology, State University of New York, 

Oswego, NY 13126. 

-Adventitious rooting in Typha glauca under experimental 

conditions. 

Overwintering sterile plants from a single clone of 

T. glauca were grown in nutrient solution with last 

year's sterile stalk either submerged or emerged to 

determine the effect on adventitious rooting. The 

following results were observed: 1) Plants with 

sterile stalks above the solution showed earliest 

rooting (within 4 days). These plants produced 

35-60 lateral roots per cm over the basal 10 cm of 

the adventitious roots. 2) Plants with submerged 

sterile stalks delayed rooting until 10 days, and 

then only after new stalks with developed aerenchyma 

had elongated 30 cm above the water surface. These 

plants had fewer adventitious roots with less lateral 

roots, except in the basal 1 cm. It was concluded 


that root development is related to the presence of 

an air pathway from above the water surface to the 

rooting zone at the base of the developing buds. 

MAUSETH, JAMES D. Dept. of Botany, University of 

Texas, Austin, TX 78712.-Development and anatom 

of the parasite Tristerix aphyllus (Loranthaceae) 

infecting Trichocereus chilensis (Cactaceae). 

Many of the large columnar cacti Trichocereus 

chilensis near Santiago are infected by Tristerix 

(= Phrygilanthus) aphyllus. This is one of the most 

highly reduced plants known: it is an endoparasite, 

the flowers being the only parts of the plant ever to 

emerge from the host, all the rest existing as an 

endophytic haustorial system; roots, stems and leaves 

are not produced. After infection, the parasite 

spreads in all directions through the thick cortex of 

the host, eventually reaching the vascular cambium 

and conducting tissues. The parasite in this 

invasive stage occurs as a "mycelium" of uniseriate 

filaments that grow between host cells, deforming 

them, but only rarely entering them. Later growth is 

by apparently random cell division that produces 

irregular parenchymatous strands. Ultimately xylem 

and phloem are produced in these strands; the phloem 

is normal but the xylem is almost pure parenchyma, 

with only occasional idioblastic tracheary elements. 

Strands close to the epidermis of the host are able 

to produce adventitious flower buds that emerge 

through either soft regions in the epidermis (the 

areoles) or through accidental breaks in it. The 

flower stalk may persist, forming a small perennial 

inflorescence that has normal wood, phloem and bark 

but is without leaves or chlorophyll. The portions of 

the endophyte that produce these exophytic inflorescences 

do not develop normal anatomy, but persist 

as irregular parenchymatous strands with small amounts 

of xylem and phloem. Host cells appear healthy and 

normal, with no sign of damage caused by the presence 

of the parasite. 

MAZE, JACK. Department of Botany, University 

of British Columbia, Vancouver, B. C. V6T 2B1, 

Canada. - Explanations for leaf development. 

The explanations offered for leaf development are 

usually causal. The most common one is that leaf 

development is the result of ontogenetic events 

that are under genetic control, the cause in this 

case being genetic. As well, kinetics, surface 

area thermodynamics, and natural laws pertaining 

to increasing disorder have been implicated in 

ontogeny and may be presented as explanations of 

leaf development. It is also possible to apply 

teleological explanations to leaf development since 

the most general form of a functional explanation 

for leaf development is the same as the most general 

form for the explanation for a vertebrate predator's 

hunting behaviour, an undoubted teleological system. 

It would thus appear that both teleological and 

causal explanations may be applied to leaf 

development. Of the causal explanations proposed, 

all would seem to be based in natural laws. 

However, causal explanations involving genetic 

control of ontogeny, using natural laws pertaining 

to chemical bonds, would not allow one to deduce 

increasing complexity with development. To do so, 

one must use natural laws pertaining to kinetics, 

thermodynamics or increasing disorder.


McCAULEY, MICHELE* and JUDITH CROXDALE. Dept. of 

Botany, Univ. of Wisconsin, Madison, WI 53706. 

-Establishment of a plastochron index for Dianthus 

Dianthus chinensis was grown under greenhouse (100 

plants) and growth chamber (25 plants) conditions to 

determine if this plant meets the three assumptions 

required for use of the plastochron index (P.T.): its 

leaves must grow exponentially in their early stages, 

grow at the same rate during the exponential phase, 

and be initiated at equal intervals. In both studies, 

one leaf of each expanded pair was measured on a regular 

basis for two months. To test the first two assumptions, 

the mean lengths of all expanded leaves 

were calculated for each day of measurement andlinear 

regressions performed over the leaves' exponential 

growth. The coefficients of determination (r2 values) 

for these lines ranged from 0.96 to 1; the slopes of 

the lines varied from 0.05 to 0.16 for the greenhouse 

plants and 0.11 to 0.26 for the growth chamberplants. 

To determine if this variation was a result of the 

averaging of leaf lengths, linear regressions were 

calculated and averaged for each leaf of each growth 

chamber plant; these slopes ranged from 0.11 to 0.27. 

A one-way ANOVA showed that the change in slopes was 

significant. The third assumption was tested by calculating 

a plastochron age for each plant for each 

day of measurement, determining the mean plastochr?n 

age, and regressing this against time. The high r 

values for the regression lines of leaf length vs. 

time indicate that in their early stages, leaves grow 

in an exponential manner. The slope values indicate 

that t e P.T. can only be used for certain leaves. 

High r values for the regression lines of mean 

plastochron age vs. time show that the leaves are 

initiated at equal intervals. The mean duration of a 

plastochron was 4.55 and 4.35 days under greenhouse 

and growth chamber conditions. The value of the P.I. 

in predicting the plastochron stage of the apex will 

be discussed. 

TTT 

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MOSELEY, MAYNARD F. Department of Biological Sciences, 

University of California, Santa Barbara, 

CA., 93106. 

Cabomba, 

Aspects of vegetative structure in 

The plant of Cabomba, as revealed by C. caroliniana, 

consists of a principal axis, which is a short-shoot 

with decussate phyllotaxy. It bears axillary, decussate 

rhizomes and flowering shoots. A rhizome may 

give rise to axillary flowering shoots or bend upwards 

to form a short shoot. Flowering shoots are 

proximally decussate or ternate, but distally, where 

flowers are borne, the phyllotaxy changes. In all 

but C, piauhyensis, phyllotaxy becomes 1/3 helical, 

and floral positions vary from axillary to extraaxillary. 

The shoots may become sympodial in C. 

aquatica and C. palaeformis. In C. piauhyensis, the 

proximal ternate phyllotaxy is essentially retained, 

but as flowers appear, one at a node, the flowers 

become extra-axillary and a larger than normal space 

occurs between the flower and its closest leaf other 

than the one it is associated with. The four positions, 

those of the three leaves and one peduncle, 

or at least of the peduncle, shift dextrorsely 600 

from one node to the next. The unoccupied space 

between two organs also shifts relative to the other 

organs. Vasculature of the vegetative axes and 

floral shoots of all but C. piauhyensis consists of 

two pairs of collateral bundles, each bundle rotated 

about 450 so that its xylem partially faces that of 

its mate. A canal, possibly a common protoxylem 

canal, lies between the bundles of each pair, and 

somewhat centripetally. Leaves have one pair of 

bundles; peduncles have three. In C. piauhyensis 

(short shoot and rhizome are unknown7Y the flowering 

shoot axes have three pairs of bundles, At each node 

of all categories of axes, an ellipticalt more or 

less continuous ellipse of vascular tissue links 

the bundles proximal to it, and from it bundles to the 

internode above and organ traces are supplied, 

MOSELEY, MAYNARD F.1, INDIRA J. MEHTA2, PAULA S. 

WILLIAMSONS and HATSUME KOSAKAI1. lDepartment of 

Biological Sciences, University of California, Santa 

Barbara, CA, 93106 and Department of Developmental 

and Cell Biology, University of California, Irvine, 

CA, 92717. - The floral anatomy of Cabomba. 

Six vascular bundles in 3 pairs supply the peduncle 

of the flower. Each pair is associated with a common 

protoxylary canal. A short, cylindrical complex of 

vascular tissue is formed in the receptacle and this 

complex is extended into a slightly distal mound, cylinder 

or arc of tissue. The basal vascular complex 

gives rise to traces for sepals, petals and stamens. 

The bases of the 3 sepals and 3 petals are arranged in 

a single whorl and may or may not be basally connate 

into a single tube. Distally, the members separate; 

petals bend centripetally and sepals centrifuga:ly. 

Each sepal and petal receives 3 to 5 vascular traces 

which are branches of a single, basal principal trace. 

Principal traces 

the same level. 

separate from the complex at about 

In 3-stamen flowers, each stamen 

stands opposite 

principal trace 

and distal to a petal and the petal 

and associated staminal trace may be 

basally connate. In 6-stamen flowers, stamens are 

aligned with the intervals between petals and sepals; 

connation of staminal and perianth principal traces 

are not frequent. The number of carpels varies most 

commonly from 1 to 3. Each carpel receives 1 principal 

trace, from the extension of the receptacular complex, 

which divides proximally to, or within, the carpellary 

base into the conventional 3, typically oriented 

veins, basally 1200 from one another. Usually, 

the 2 ventral veins meet in the center of the distal, 

ventral ovarian region. Positions of the anatropous, 


ovular attachments may be to the interior wall over 1 

or more of the veins, or any position between 2 veins 

including a central position over the union of the 

ventral veins. Ovular vascular supplies are very 

variable, but appropriate. 

MUELLER, RICHARD J. Department of Biology, Utah 

State University, Logan, UT 84322 - Architecture 

and development of sylleptic branch_ing in Alstonia 

schol ari s (Apocynaceae). 

The tropical tree Alstonia scholaris exhibits modular 

branching and belongs to Prevost's model in the 

Halle and Oldemann architectural classification. The 

tree consists of a main trunk and plagiotropic, sympodial 

lateral branches. Each lateral branch module 

consists of a long basal internode, two whorls of 

6-10 foliage leaves and a distal whorl of four 

scale leaves. The shoot apex of each branch becomes 

parenchymatous or produces a terminal inflorescence 

to end the growth of each module. During vegetative 

growth, a new branch arises in the axil of each of 

the scale leaves. The initiation and development of 

these branches was investigated. The diameter of 

the shoot apex reaches a larger maximum size during 

successive plastochrons of the lateral branch module. 

Therefore the smallest leaves (scale type) are initiated 

from the largest shoot apical meristem. The 

occurence of this unusual phenomenon is related to 

the nearly simultaneous initiation of the large 

buds of the sylleptic branches in the axils of the 

scale leaves. The formation of these buds consumes 

most of the tissue of the broadened apex. The initiation 

of the scale leaves, the formation of their 

axillary buds, and the parenchymatization of the 

central region of the original shoot apex are closely 

associated temporally and morphologically. 

NIKLAS, KARL 

J. Section of Plant Biology, 

Division of Biological Sciences, Cornell 

University, Ithaca, NY 14853. - 

Morphological consequences of the efficient 

display of photosynthetic tissues: implications 

on early land plant evolution. 

Conventionally, the evolution of increased plant 

stature has been related to the selective advantages 

of discharging spores at greater heights and of 

displaying photosynthetic surfaces above adjacent 

vegetation. The consequent changes in photosynthetic 

efficiency (I), resulting from alterations in plant 

geometry, are assessed by means of computer simula- 

tions and a model relating I to the projected sur- 

face area to total surface area (Ap/A) of a plant's 

photosynthetic tissues. The evolutionary appearance 

of orthotropically growing cylindrical and bifur- 

cating axes is demonstrated to be one developmental 

response capable of optimizing I. In addition, a 

trade bff between I and the mechanical stability of 

high order branching systems (defined by the total 

moment arm, M) is shown to result in the appearance 

of overtopped, tree-like morphologies. Multidimen- 

sional plots of I, M, and geometric features of 

branching result in three-dimensional topologies 

with "peaks" corresponding to I and M . . Self- 

crowding and self-shading of higier ordeN1Branches 

can be resolved by compartmentalizing supporting 

(branches) and photosynthetic (leaves) organs. This 

results in computer simulations analogous in 

structure to the morphologies or various fossil and 

extant plants.


OKATAN, YENER and OLGUN, GWKSEL. Department of 

Biology, University of Istanbul, Turkey. Depart- 

ment of Biology, University of Trakya, Turkey. 

- Hormonal relations between vegetative and repro- 

ductive structures in monocarpic plants.I. The 

pattern of senescence in Digitalis purpurea L. and 

some developmental changes brought about by par- 

thenocarpy. 

In this study, the effects of parthenocarpy on senes- 

cence and on the other aspects of development of Di- 

gitalis purpurea L. were investigated. Unpollinated 

flowers of the plant were treated with gibberellin 

after emasculation. With this method, 100% partheno- 

carpic fruits were obtained. The number of flowers 

per plant was observed to increase by 109% the period 

of flowering by 131% and the growth of flower stalk 

by 107% in plants with parthenocarpic fruits. Similar 

observations were made on plants deflowered before 

pollination. On the other hand, in untreated plants 

with normal fruits, flowering was found to cease with 

the mature of the fruits. These observations suggest 

that senescence occurs as apical senescence in the 

plant D. purpurea and that this is induced by the 

development of the seeds. 

OLGUN, GiKSEL and OKATAN, YENER. Department of Bio- 

logy, University of Trakya, Turkey. Department of 

Biology, University of Istanbul, Turkey. 

- Some ultrastructural changes in the mesophyll 

chloroplasts of the podded and the deflowered 

soybean plants. 

During the vegetative growtl or pod-fill period, no 

destruction occurs in the thylakoid membranes. Cessa- 

tion of the vegetative growth in deflowered plants or 

maturation of the seed on the podded plants lead to 

accumulation of starch granules in the chloroplasts 

of the young leaves. Thylakoid membranes look like 

intact but suqueezed by starch granules. As the senes- 

cence starts in the Dodded plants, thylakoid mrembranes 

are destructed, osinophylic bodies appear, starch gra- 

nules disappear. Regular senescence dose not occur in 

deflowered plants. Thylakoid membranes remaih intact. 

But, neither osmiophylic bodies nor starch granules 

are seen as dense as to be expected. 

ORR, ALAN R.,* W. BRADFORD, and L. LOVE. 

Department of Biology, University of Northern 

Iowa, Cedar Falls, IA 50614. 

- Cytochrome oxidase activity in the shoot 

apical meristem of Brassica campestris L. 

during transition to flowering. 

Histochemical studies on fresh-frozen, cryostat 

sections of evoked shoot apices of Brassica 

campestris showed there was an increase in 

cytochrome oxidase activity within the first 24 

hr after plants were transferred from short days 

(8 hr light) to long days (16 hr light). Cytochrome 

oxidase activity was observed in the central, 

peripheral and pith-rib meristem zones of the 

meristem at the transition stage. Activity in the 

late transition stage was localized in areas of 

the peripheral zone where floral bud primordia 

would be formed. These observations support an 

interpretation of floral evocation in a transforming 

meristem of Brassica as consisting, at least 

partially, of a higher respiratory rate than the 

vegetative meristem of Brassica. Results are 

discussed in relation to other histochemical and 

cytological events which are known to occur in the 

meristem of Brassica. 

JOHN. N. OWENS. Biology Department, University of 

Victoria, Victoria, B.C. V8W 2Y2. - Cone bud 

development and shoot growth in Douglas-fir under 

GA4/7 and root pruning treatments. 

The time and method of cone initiation has been determined 

for many conifers. Cone induction has been 

accomplished 

members of 

using gibberellin 

the Pinaceae. Cone 

A4/7 (GA4/7) in 

induction in the 

16 

Pinaceae 

appears to be most successful when GA417 isused 

in conjunction with cultural treatments such as root 

pruning. This paper reports on the development of vegetative 

and potential 

root pruned and GA4/7 

juvenile Douglas-fir. 

cone buds under control, GA4/7, 

plus root pruned conditions in 

Trees with a flowering history 

and trees with no flowering history were assigned to 

each of the four treatments. One group of 80 trees 

was used for analysis of the general coning response, 

at the end of the growing season. In a-second group 

of 16 trees, shoot elongation was,measured weekly, 

other shoots were collected weekly, and developing 

terminal and axillary buds were sampled for anatomical 

study. This paper describes axillary bud development 

as it relates to shoot elongation and cone bud differentiation. 

Flowering was significantly increased by 

the GA4/7 

and root pruning treatments. 

of this response was mediated by the 

The magnitude 

trees flowering 

history. Shoot growth was reduced by root pruning 

regardless of flowering history and was increased by 

GA4/7 only in trees having a poor flowering history. 

Terminal and axillary bud development had the same 

phenology and time of cone bud differentiation as in 

mature trees growing under natural conditions. Root 

pruning with and without GA4/7 reduced mitotic activity 

in distal potential vegetative and potential conebud 

apices. The possible relationship between treatment, 

shoot elongation, apical development and cone 

bud differentiation will be discussed. 

PALSER, BARBARA F. Department of Biological Sci- 

ences, Rutgers University, Piscataway, NJ 08854 - 

Floral anatomical and embryological evidence bear- 

ing on the segregation of Harrimanella from 

Cassiope (Ericaceae). 

Two species of Cassiope, stelleriana and hypnoides, 

have been segregated as species of Harrimanella on 

the basis of gross morphology and leaf anatomy. Elev- 

en taxa, including these two, have been studied and 

compared for several floral characteristics. All are 

pentamerous, pentacyclic, actinomorphic, sympetalous, 

and hypogynous, the appendaged anthers inverting to 

introrse rather late in development. More or less 

variation, however, is found in other features: vascue 

lar anatomy, peduncle hairs, sepal anatomy and stoma- 

ta, corolla shape at base, anther shape and dehis- 

cence, nectary shape and stomata, style shape, ovary 

stomata--particularly internal, ovule size and number 

megagametophyte development and mature structure. In 

most of these characters stelleriana differs from all 

the others except hypnoides, thus supporting its 

segregation in a separate genus. The case is less 

clear for hypnoides. This species agrees with 

stelleriana in several characteristics, the most sig- 

nificant being a Polygonum type of megagametophyte 

development in contrast to the Allium type found in 

all other species. It agrees with the nine other 

taxa in a few characteristics and is intermediate in 

several others, such as the mode of anther dehiscence 

(collapse vs. resorption tissue/Barrimanella vs. 

Cassiope). On the whole, hypnoides appears to have 

enough characters in common with stelleriana to be 

included with it in Barrimanella.

PETERSON, CURT M.* and MICHAEL W. FOLSOM. Depart- 

ment of Botany, Plant Pathology, and Microbiology 

and the Alabama Agricultural Experiment Station, 

Auburn University, AL 36849, and Department of 

Botany, University of Alberta, Edmonton, Alberta, 

Canada T6G 2E9. 

- The effect of a cytokinin on flower and pod 

abscission of soybean, Glycine max (L.) Merr. 

Abscission of flowers and immature pods accounts for 

most of the reduction in yield potential of soybean 

(Glycine max (L.) Merr). Terminal racemes of 

'Bragg' soybean plants were sprayed with 10-, 10- 

or 10-3M 6-benzylaminopurine (BAP) to determine the 

influence of a cytokinin on flower and pod abscissior. 

A significant reduction in abscission occurred only 

when 10-3M BAP was applied. A significant increase 

in the total number of seeds per plant also was 

observed for the 103M BAP treatment. This was due 

entirely to an increased number of pods per raceme, 

because there was no difference in the mean number 

of seeds per pod. Most abscissions within each 

treatment occurred during the first 14 days of the 

treatment period. The effect of BAP in reducing 

abscission was observable within 10 days after spray- 

ing. All mature pods of control plants were located 

at the first seven (proximal) nodes on terminal ra- 

cemes. Compared to other treatments the increased 

number of mature pods following 10-3M BAP treatment 

was due to a significantly higher number of mature 

pods at nodes distal to node 7. Changes in distal 

shoot morphology were observed on some treated plants 

suggesting that BAP may alter reproductive develop- 

ment to favor increased pod set in soybean. 

PnT'nOLY TOTIN J.* "Tew York Botanircal '-rden, IBronx, 

NY 1fl453 nnrv ~),.'TIS 'Nf, STEJx7ENSO'\J, larnarr1 Coi1ee 

of Colurmibira TTnive.rqi.tv, 'TY 1(),)27. - PhvllotAxis, 

ste?nr mornTol1oov and shoot ani.cal organization rof 

T.v conodtlimt annre.s sum (TL.vcnodiaceae) . 

ThvI-otnxis consists or i svste.n of alternatino 

nsendowhorls 

cCOrre-sPnQs 

witeh a 2/1 Ti-ivIlotactic 

tn a o+O contact nar.atiai 

sn-tral whlrch 

system wr.th 

13 orthlosti.chlos. Eachi of the six stelar lobehs is 

svm.poliun of the. leaf tracps oF thlree nrtqosticlilns 

afld i.5 eenn of th~ree nrot.oxvlern noles. ANt th-e 

verv lenst, the otitt,.r reginn of t'sA. stele is CoTnroqed 

of leaf traces and is t'verefore not corinleteiv 

mtitonomous. The. s'rnotc an?x con.si.sts of Sotxr zones3 

whiich mav he rpcnf 7:lr4 both cvtolo"icn1llv an.d 

h-iistr,chp?irn.v, as foliow7s: suirface initials, 

subizilrface in1ti.i1 , rii1 r'ier1stern, ond ne.riphrwta.l 

rneristemn. The c{.ff freni


REYNOLDS, THOMAS L. Department of Biology, 

University of North Carolina, Charlotte, NC 28223. 

- An ultrastructural and stereological analysis of 

pollen grains of Hyoscyamus niger during induced 

embryogenic development. 

Selected nuclear and cytoplasmic changes during 

embryogenic development, induced by the culture of 

anther segments of H. niger, were analyzed using 

stereological techniques for morphometry. When pollen 

grains were cultured at the uninucleate stage of 

development, potentially embryogenic grains could be 

identified within 6 h of culture by an increased 

area fraction of the nucleolus occupied by the 

granular zone. The ratio of dispersed to condensed 

chromatin in the nucleoplasm of these cells also 

increased. Nonembryogenic pollen in vitro and in vivo 

possessed prominent fibrillar zones in the nucleolus 

and a relatively constant ratio of dispersed to 

condensed chromatin. These differences may reflect 

changes in nuclear activity in potentially embryogenic 

pollen grains during early stages of culture. 

Following the first haploid mitosis, the nucleolus of 

the generative cell in potentially embryogenic pollen 

maintained an extensive granular zone through the 

first division to form a proembryoid. On the other 

hand, the nucleolus of the vegetative cell became 

primarily fibrillar and the cell did not divide. The 

area fraction of the cytoplasm occupied by RER, Golgi 

cisternae, mitochondria, and plastids differed in the 

generative cells of potentially embryogenic and nonembryogenic 

pollen. These results support the idea 

that embryogenic induction in H. niger takes place at 

the uninucleate stage of pollen development and that 

the first division of the potentially embryogenic 

generative cell to form a bicellular proembryoid 

completes the induction process. 

Richards, J.H. and S.C.H. Barrett. Dept. of 

Biol., Fla. International U., Miami, FL 

33199 and Botany Dept., U. of Toronto, Tor- 

onto, Ontario, M5S lAl. Developmental 

basis of tristyly in Eichhornia paniculata 

Spreng. (Pontederiaceae). 

Eichhornia paniculata is a short-lived per- 

ennial, emergent aquatic. The species is 

tristylous but self-compatible. Growth is 

sympodial. When flowering, paniculate in- 

florescences bear flowers alternately on 

first-order branches. Long, mid and short- 

styled morphs occur in the majority of Braz- 

ilian populations. A flower of a given morph 

has a style of one length and six stamens, 

three each of the other two lengths. Stamen 

insertion is dorsiventral. Within a flower, 

the relatively longer stamens are found on 

the lower side of the flower, while the rel- 

atively shorter stamens are on the upper side. 

Anther size is positively correlated with 

stamen height. 

The general pattern of flower development 

does not differ between morphs. Flower prim- 

ordia are triangular at initiation. Stamens 

arise in two whorls of three each in conjunc- 

tion with tepal origin on the flat primordium 

apex. The three horseshoe-shaped carpel pri- 

mordia arise simultaneously after the second 

set of stamens. Thus, initial organization 

of the flower is radial. Differences between 

the two stamen levels in size and number of 

microsporocytes are seen in anthers prior to 

meiosis. Meiosis occurs in buds app. 1 mm 

long. Thus the dorsiventral pattern of dev- 

elopment first seen in the microsporocytes 

alters the initial radial pattern of growth. 

RIDING, RICHARD T. Department of Biology, 

University of New Brunswick, Fredericton, 

New Brunswick, Canada E3B 6E1. 

-Structure of needles of Pinus radiata as influ- 

enced by light intensity or moisture stress. 

Trees from four clones were grown in growth rooms 

at the New Zealand Forest Service, Forest Research 

Institute in Rotorua. Current year needles, 

collected from different heights in the crowns 

of these trees, yielded foliage samples from four 

light intensities per clone. Needle size increased 

with increasing light intensity. This was accom- 

panied by an increase in the number of hypodermal 

layers, mesophyll layers, and resin ducts. The 

ratio of vascular tissue to needle cross-sectional 

area remained fairly constant; however, the dis- 

creteness of the two vascular bundles decreased 

as stelar size increased. Although the 'structure 

of epidermal cells and the stomatal complex did 

not vary with light intensity, the number of sto- 

matal rows and stomatal frequency tended to in- 

crease with increasing light intensity. The influ- 

ence of vapour pressure deficit (VPD) on needle 

structure was determined for plants from 3 clones 

grown under 3 different conditions of atmospheric 

moisture. The needles with the smallest cross-sec- 

tional area were from dry conditions while the 

thickness of the dermal system was greatest for 

plants grown under moist conditions. The number 

of resin ducts per needle increased with decreas- 

ing VPD. Again, the structure of the stomatal 

complex was constant for all conditions. In both 

studies there was clonal variation. 

(Supported by grants from NSERC Canada. Thanks 

are due D.R. Smith and D.A. Rook of the Forest 

Research Institute.) 

ROST, THOMAS L., PRIMAVERA IZAGUIRRE DE ARTUCIO* 

AND EDWARD B. RISLEY. Department of Botany, Uni- 

versity of California, Davis, CA 95616; *Facultad 

de Agronomia, Universidad de la Republica Uruguay, 

Montevideo, Uruguay - Transfer cells in the 

placental pad and caryopsis coat of Pappophorum 

subbulbosum Arech. (Poaceae). 

During caryopsis development the layers of the peri- 

carp, integuments and nucellus all contribute to the 

formation of the caryopsis covering structures. The 

caryopsis coat is continuous around the entire cary- 

opsis except at the style remnant and placental con- 

nection. The coat consists of a discontinuous outer 

pericarp epidermis transfer cell layer, crushed and 

senescent middle pericarp layers and a continuous 

inner pericarp epidermal transfer cell layer. This 

last layer, however, is not present across the pla- 

cental pad. The integuments are present as a crushed 

dense layer, the nucellus is a discontinuous, thin 

and crushed layer. The placental pad occurs at the 

ventral surface of the caryopsis opposite the scutel- 

lum and coleorhiza. It consists of 15-20 crushed 

cell layers, including the remnant of the placental 

vascular bundle. From the inside several partially 

crushed nucellar layers occur that contain transfer 

cell walls. The middle dense layers, the pigment 

strand, consist of the middle pericarp remnant, plus 

the placental vascular bundle remains. The inner 

pericarp epidermis and aleurone layers do not extend 

across the pad. The outer pericarp epidermis extends 

across the entire pad as a connected layer of trans- 

fer cells. These cells contain membranous structures 

suggesting that they may be living cells, possibly 

functional in the mature caryopsis.

RUGENSTEIN, SEANNA R. Department of Botany, 

Louisiana State University, Baton Rouge, 

LA 70803. 

- Seed testa patterns in Cercideae 

(Caesalpinioideae: Leguminosae). 

The caesalpinioid legume tribe Cercideae contains 

six genera in two subtribes. Scanning electron 

microscopy was utilized to study the anatomy of 

seeds of 60 species representing 25% of the species 

in the largest subtribe and 83% of the species 

in the second. Several features of papilionoid 

legume seed anatomy have been shown to have 

taxonomic utility (Gunn, 1981; Kupicha, 1977; 

Lersten and Gunn, 1982). It was determined, 

during this study, that testa patterns in 

Cercideae differed in size rather than basic 

configuration, from those on papilionoid 

legume seeds. The basic testa patterns 

in Cercideae, as in papilionoid legumes, 

are papillose, reticulate, and foveolate. 

Other features of Cercideae seed anatomy, 

such as size and shape of hilar tongue, 

hilar groove, and micropyle, were also 

examined. The distribution of these anatomical 

features of the Cercideae seed seem to be 

indicative of subtribal and subgeneric 

taxonomic affiliations. 

RUSSELL, SCOTT D. Department of Botany and 

Microbiology, University of Oklahoma, Norman, OK 

73019 - Gametic fusion in Plumbago zeylanica: 

Ultrastructural evidence for gamete recognition and the 

preferential transmission of sperm plastids into the 

zygote. 

The mature microgametophyte of Plumbago zeylanica 

contains two dimorphic sperm cells which may be identi- 

fied by differences in both morphology and cytological 

content. One of the two male gametes is associated with 

the vegetative nucleus throughout its later development 

and is distinguished by the presence of a 30 micrometer 

long cellular projection which wraps around the vegetative 

nucleus. Cytological content of this sperm cell includes 0 

to 2 plastids and an average of 256 mitochondria. The 

other sperm cell is connected to the first sperm by 

plasmodesmata, is not closely associated with the vegeta- 

tive nucleus and lacks a prominent cellular projection. The 

second sperm cell contains 8 to 48 plastids and an average 

of 40 mitochondria. Upon discharge of the gametes from 

the pollen tube, both sperm cells are deposited in an 

intercellular region within the female gametophyte, 

located between the egg and central cell. The distinctive 

morphology of sperm plastids after fertilization can be 

used as a naturally occurring cytoplasmic marker to deter- 

mine which of these two sperms fuses with the egg and 

central cell. Evidence to date has suggested a preferential 

pattern of fusions between the plastid-containing sperm 

and the egg cell, transmitting a number of plastids into the 

incipient embryo. The other, plastid-poor sperm fuses with 

the central cell, transmitting numerous mitochondria into 

the incipient endosperm. This preferential pattern of 

organelle inheritance strongly suggests that gametic fusion 

in the megagametophyte is not random in P. zeylanica. 

These results provide evidence for the presence of a final 

putative barrier to reproduction consisting of a gamete- 

level recognition system which may operate in the male 

and female gametes of this angiosperm. 

SANGSTER, ALLAN, G. Division of Natural Sciences, 

Glendon College, York University, Toronto, Ontario, 

M4N 3M6 

-Anatomy and silica distribution patterns in root 

and rhi zome of the grass Mi scanthus sacchari fl orus . 


Anatomy and deposited silica distributional patterns 

were investigated for the root and rhizome by means 

of scanning electron microscopy and energy dispersive 

X-ray microanalysis. In the root, silica deposits 

were confined to the single-layered endodermis in the 

form of large aggregates. In the rhizome, silica was 

present in two concentric regions consisting of the 

outer endodermis and the cells bordering the inner 

central cavity. Both these regions were several- 

layered, and the deposits were part of the cell wall 

layers rather than projecting aggregates. In both 

organs, a perivascular distribution pattern was 

evident, single-layered in the root but multi-layered 

in the rhizome. The root pattern is consistent with 

that investigated for other genera of the tribe 

Andropogoneae, as is the endodermal deposition site 

for the rhizome. However, rhizome deposits differ 

in form from other genera, and deposition around the 

central cavity has not been encountered previously. 

SCRIBAILO, ROBIN W. and U. POSLUSZNY, Department 

of Botany and Genetics, University of Guelph, 

Guelph, Ontario, Canada NlG 2W1 

- Morphology and establishment of seedlings of 

Hydrocharis morsus-ranae. 

Hydrocharis morsus-ranae is an introduced aquatic 

plant species in North America. Little is known 

concerning the nature and morphology of seedling 

germination in this species. Consequently it has 

been assumed that Hydrocharis morsus-ranae must 

overwinter primarily through the production of large 

numbers of vegetative propagules. As part of a 

continuing study of this species an S.E.M. and field 

investigation of the seed and seedling morphology 

were initiated to contribute to the limited know- 

ledge of germination patterns within this genus and 

the Hydrocharitaceae as a whole. The seeds of 

Hydrocharis morsus-ranae are highly unusual morpho- 

logically having their entire surface covered with 

hollow spiraliform tubercles. Germination occurs 

when the embryo of the exalbuminous seeds elongate 

splitting the tuberculate testa. The buoyant 

developing embryos then rise to the surface and the 

first foliage leaves emerge from a highly modified 

cotyledonary sheath. The young seedlings undergo 

several growth phases in which they first appear 

lemnid in habit before attaining their character- 

istic reniform leaf shape. In the field, substantial 

numbers of Hydrocharis morsus-ranae seedlings were 

found germinating among the turions of the same 

species. It is likely that reproduction from seed 

is more important in this species than previously 

thought. 

SHULTZ, LEILA M. Department of Biology, Utah 

State University, Logan UT 84322. - Leaf vessel 

measurements in desert perennials. 

The relationship of habitat and leaf vessel 

measurements is explored in comparative anatomical 

studies of sixteen closely related taxa (Artemisia 

spp.) from the cold deserts of western North America. 

Data are presented which document changes in vessel 

structure as well as relative volumes of tracheary 

tissue in habitats which are defined by a gradient 

of increasing aridity. As might be expected, vessel 

diameters decrease and width of cell walls increase 

with increasing aridity. Few studies, however, have 

addressed the possibility of volumetric changes in 

tracheary tissue. The relative volume of xylem to 

total tissue volume in the leaf appears to be a 

sensitive indicator of water stress. That ratio is 

presented and discussed here as a Xeromorphy Index.


SLONE, J .-HENRY* and RICK G. KELSEY. Departments 

of Botany and Chemistry, University of Montana, 

Missoula, MT 59812. 

- Structural and histochemical studies of glandu- 

lar trichomes of Artemisia tridentata ssp.vaseyana. 

Fresh and plastic embedded buds and leaves were stain- 

ed and observed by light microscopy. The gland has 

ten cells (2 rows of 5 cells), including a pair of 

epidermal basal and a pair of stalk cells below a six- 

celled head. Mature glands accumulate terpenoid se- 

cretion products that react with conc. H2SO4 and also 

secrete small amounts of polysaccharide particles 

within a distended cuticle above the upper 2-3 tiers 

of head cells. In younger leaves, the glands occur 

as populations of mixed developmental stages. Older 

leaves support mainly senescent and collapsed glands. 

Chloroplasts are present in the lower and middle tiers 

but not in the upper tier of head cells, nor in the 

stalk and basal cells. The cytoplasm of early secre- 

tory glands stain lightly and uniformly for polysac- 

charides. In mid- to late secretory glands, the stalk 

cell constituents stain intensely for polysaccharides. 

Toluidine blue 0, on the other hand, stains stalk 

cells intensely blue-green, but stains head and basal 

cells light blue in glands of early secretory stages. 

Glands at later secretory stages exhibit a preferen- 

tial staining for protein at the periphery of the cy- 

toplasm adjacent to the anticlinal and distal peri- 

clinal walls of the upper two tiers of head cells. 

The cellular contents (including small spherical bod- 

ies) of secretory glands stain with Sudan Black B, 

but presecretory glands do not. Sudan IV only stains 

cuticle. Sudan Black staining of the cytoplasm is 

probably due to phospholipids. As glands enter into 

the late secretion phase, cytoplasmic constituents be- 

come less distinct, the chloroplast stains less for 

protein, and the plasmalemma of the head cells detach 

from the cell wall. 

SPERRY, JOHN S. Department of Biology, Harvard 

University, Harvard Forest, Petersham, MA 01366. 

- Hydraulic architecture of the palm Rhapis excelsa. 

Resistance to flow (R), and pressure gradients (AP/1) 

along the stem-to-leaf xylary path under average flux 

rates (J) were investigated in aerial axes of Rhapis 

excelsa and related to xylem structure/development. 

R measurements were made on excised axes, and show a 

consistent pattern for the mature vascular path: Rper 

unit length is lowest in the stem (-7 bars . s(ml . cma1), 

highest in the leaf base (-34 bars . s(ml . cm)Y1, and 

intermediate in the petiole (-18 bars . s(ml . cm) ). 

Results reflect vascular anatomy: the stem has wide 

(75-100pm) metaxylem (mx) vessels, the leaf base has 

narrow (to 25um) protoxylem tracheids, and the petiole 

has intermediate mx vessels (35-60pm). R has a con- 

sistent relationship to leaf age: the youngest ex- 

panded leaf (ELl; second-youngest = EL2, etc.) has 

relatively high R (e.g. 6600 bars . s . m11), R de- 

creases with leaf development to minimal value in 

EL4,5 (e.g. 2500 bars . s . ml1). Senescent leaves 

have R comparable to ELl. Decrease in R with leaf 

development correlates with the basipetal maturation 

of mx in the leaf axis which is not complete until 

EL4. Increased R in senescent leaves is due to xylem 

dysfunction in the leaf base. J was estimated from 

transpiration; variation with leaf age shows the in- 

verse trend of R: ELl has low J (e.g. 9.lxlO ml . S- 

older leaves show progressively higher J to maximum in 

EL4 (e.g. 63xlO04ml . s l). J in senescent leaves is 

similar to EL1. AP/l calculated from J and R indi- 

cates recently mature leaves (EL4,5) are routinely 

subject to lower sap pressures than developing and 

senescing leaves. The bottleneck at the leaf base 

accounts for a large portion of the pressure drop 

into the leaf: at maximum J it induces a drop of 7 

bars. This bottleneck may act to confine sap cavi- 

tations to the leaf axis, thus preserving hydraulic 

integrity of stem xylem. 

STEINGRAEBER, DAVID A.* and JACK B. FISHER. Department 

of Botany & Plant Pathology, Colorado State 

University, Fort Collins, CO 80523 and Fairchild 

Tropical Garden, Miami, FL 33156. - Indeterminate 

growth of leaves 

analogue. 

in Guarea (Meliaceae): a twig 

Leaves of seed plants are generally characterized as 

organs of determinate growth. In this regard, Guarea 

and related genera seem unusual in that their pinnately 

compound leaves contain a bud at their tip 

from which new leaflets expand from time to time. 

Previous studies based upon superficial examinations 

of leaf-tip buds have produced contradictory conclusions 

regarding how long the leaf apex remains meristematic 

and produces leaflet primordia. In order 

to determine whether leaf development iii Guarea is 

truly indeterminate, we microscopically examined 

leaf-tip buds of Guarea guidonia and G. glabra. In 

both species, the leaf apex remains meristematic and 

continues to produce new leaflet primordia as the 

leaf ages. Unexpanded leaves of G. guidonia contained 

an average of 23 leaflet primordia, while the 

oldest leaves we examined had initiated an average 

of 44 total leaflets. In G. glabra, unexpanded 

leaves contained 8 leaflets, whereas an average of 28 

leaflets had been initiated on the oldest leaves. 

Periodic examination of individual intact leaves indicated 

that the leaves may continue their growth for 

2 or more years. As new leaflets are initiated at 

the leaf apex (and subsequently expand in rhythmic 

flushes), older (basal) leaflets may abscise. In 

addition, the rachis of the leaf thickens and becomes 

woody due to the activity of a vascular cambium. 

Guarea leaves thus seem to be analogous to a typical 

twig (stem), in general habit as well as in their 

indeterminate apical growth and secondary thickening. 

;T',VENSflT, DF:11IS Tr Ba 1rnTarl College. of Columnhia 

TTniversitv, NeTw7 York 10027 and Nevr 'Ynrt, Botanical 

r,qrden, Bronx, 'TY 1)458. - Svsternatic innl.icntions 

of t'ie fl.oral nornholotzv of the. favaceae. 

s'frzt.ti"tFe.1v., th15. nfnoonPric aituittic F-imlv7 most 

closeliv 

flratesihr,~, 

nt?nT-krqr of 

o-r+ rlr .nirl1.- indicatebletit- 

l5z,Mtim?taeqo 

thrint it. Is rvnr-. 

",1prea?; 

rrornerlv 

'ni~ic~ . . n thl t ro e1 5nIl qg. Ttile rf 1 r),7 , r-Iv rt i -, s i n Tvlv - 

4in t'ie -Xils, inr'r 1i7 vascni1-.ir_%A l)-ant.s mnd t.lle 

ve.-etntive branchd?; ir tlie axils nF vee!ntptive 1eives. 

titSs*1

infected with vascular pathogens appear adjacent to 

vein endings. Terminating vessel members in leaves 

may be sites of accumulation of pathogen metabolites, 

degraded cell wall components or wound reactants. 

Anatomical studies of these terminal vessel members 

has provided scant evidence for their importance in 

vascular wilt disease and has centered on phylogenetic 

comparisons of terminating vessels. Our study there- 

fore was aimed at a detailed anatomical appraisal of 

terminating vessels especially the structure of end 

walls. Leaves of tomato, chrysanthemum, alfalfa and 

hop were prepared for electron microscopy and serially 

sectioned from the tip. Tips of all terminal tracheids 

narrowed rapidly towards the ends and no perforation 

plates were observed. Tracheids ended either singly 

in chrysanthemum, tomato and hop or in pairs in alfalfa. 

Chrysanthemum and alfalfa endings were closely ad- 

pressed to parenchyma cells with little discernable 

distinction between the walls of both cells. This 

intimate association suggested a free transfer of 

xylem fluids through walls in the symplast. Tomato 

and hop endings were positioned in areas of less 

coherence being surrounded by many intercellular 

spaces. All the tracheid tipswere triangular in cross- 

section and extensively thickened. The endings con- 

tained many pit surfaces and in chrysanthemum there 

was a characteristic tail which appeared to be composed 

of secondary thickened laminar fibres. Extensive 

accumulation of granular phenolics in the lumens of 

some tracheid tips suggested that this area was 

particularly susceptible to aggregations of plant and 

fungal metabolites which might contribute towards 

water flow restriction to leaf mesophyll cells and 

ensuing vascular wilt symptoms. 

TUCKER, SHIRLEY C. Department of Botany, 

Louisiana State University, Baton Rouge, LA 

70803 

- Character weighting in Leguminosae based on 

time of initiation. 

Unifying ordinal or familial characteristics are by 

definition stable. These features should therefore 

be determined early in floral ontogeny, while those 

characteristics which separate related species 

should occur relatively late in ontogeny. Examples 

of early-determined features (to be illustrated with 

examples from Leguminosae) include floral symmetry, 

order of appendage initiation, number and kinds of 

whorls, number of parts per whorl, and order of 

initiation within a whorl. A second assemblage of 

characteristics is determined in mid-development 

stages; these include corolla aestivation, organ 

abortion to produce "loss", elongation of some parts, 

tube formation of calyx, corolla, and androecium, 

petal fusion, differential growth of petals, differ- 

ential growth of the two stamen whorls, and forma- 

tion of gynophore and staminodes. Some of these 

mid-development-determined characteristics are im- 

portant in producing supra-generic distinctions, 

while others are more important at the generic level. 

Late-determined characteristics, which are likely to 

distinguish related species or sometimes genera, 

include differential changes in petal shape, petal 

color, filament elongation, nectaries, nectar and 

fragrance, epidermal elaborations (hairs, sculp- 

turing, hooks, pits, cuticle), and changes in carpel 

shape. Although exceptions abound to these gen- 

eralizations, the hypothesis offers a useful ap- 

proach to re-examining and evaluating diagnostic 

characteristics in the light of their ontogenetic 

origin. 


TUCKER, SHIRLEY C. Department of Botany, 

Louisiana State University, Baton Rouge, LA 

70803 

- Developmental origins of petal aestivation in 

Cadia purpurea and other legumes. 

Although petal aestivation is used to separate sub- 

families and some tribes of legumes, there is little 

developmental evidence on its control in these 

groups. Valvate aestivation typifies Mimosoideae, 

ascending cochlear aestivation typifies Caesal- 

pinioideae, and descending cochlear typifies Papi- 

lionoideae. Petals are widely spaced and not imbri- 

cate at initiation, nor do the bases extend margi- 

nally to become imbricate. Overlapping occurs at 

the margins about halfway up the petals when they 

are about 300 pm high. Features which determine 

which petal overlaps outside another include rela- 

tive size, thickness, and degree of curvature of the 

petal in transsection. Petals which overlap have 

relatively attenuate margins, while those which ap- 

press and fuse have thick, blunt margins. Cadia 

purpurea, in the primitive papilionoid tribe Sopho- 

reae, appears intermediate to the Caesalpinioideae 

because of its highly variable petal aestivation. 

Ascending cochlear and descending cochlear patterns 

are both common among flowers on the same plant. 

Also, two patterns occur which are rare in the le- 

gumes: 1) a pattern in which the standard petal is 

half inside, half outside the wings, and 2) com- 

pletely quincuncial. Developmentally, Cadia's petal 

enlargement is delayed greatly, compared to other 

taxa. All the petals remain the same size and shape 

throughout development. When the petals finally 

approach one another, the pattern of overlap appears 

to be a matter of chance, unlike the pattern in most 

legumes. 

VERBEKE, JUDITH and DAN B. WALKER. Department 

of Biology, UCLA, Los Angeles, CA 90024 

- Characterization of the mechanism underlying 

induced epidermal dedifferentiation in the fusing 

carpels of Catharanthus roseus. 

In the process of floral ontogeny in Catharanthus 

roseus approximately 400 epidermal cells are induced 

to dedifferentiate during the postgenital fusion of 

the two carpel primordia. Previously reported ex- 

periments involving the placement of gold foil 

barriers between prefusion carpels have showm that 

dedifferentiation occurred only at points of direct 

cell-to-cell contact. The morphogenetic stimulus in 

this system may, therefore, consist of either a 

diffusible messenger molecule or some kind of cell 

surface interaction. To characterize the mechanics 

of the induction of dedifferentiation we placed 

barriers of various types between the pre-fusion 

adaxial surfaces and monitored epidermal develop- 

ment as the carpel faces grew into contact. Plastic 

barriers (which permitted the diffusion Of 02 and 

CO2 but which prohibited the diffusion of water) 

blocked dedifferentiation of the contacting epider- 

mal cells, giving a response similar to that pre- 

viously reported with the gold foil barriers. 

Polycarbonate membranes of knowm porosity which can 

allow for passage of water soluble agents did not 

block dedifferentiation of the contacting epidermal 

cells. Thus, it appears that a diffusible agent is 

involved in an intercellular communication that 

triggers the dedifferentiation response. Current 

efforts are aimed at better characterizing the 

agent(s) .


WALKER, DAN B. Department of Biology, UCLA, 

Los Angeles, CA 90024 

- Assessment of positional ceU differentiation 

in plants and a proposed model. 

Evidence from work in my laboratory and from 

published reports will be discussed, and a model 

proposed to explain aspects of cellular pattern 

formation. Both descriptive and experimental data 

indicate that epidermal and vascular tissues have 

fundamentally different mechanisms of ontogeny 

which probably evolved independently. A model to 

explain the patterning of plant tissues will be 

proposed that incorporates these different mechanisms 

as key positional indicators of cell differentiation. 

Major tenets of the model include the following. 

Positional information to control when and where 

patterned differentiation of cells occurs results 

frcm cell-to-cell ccmmunications between adjacent 

and nearby cells. Diffusible morphogens effect 

this communication, but these morphogens are not 

the major phytohormones, which play only an indirect 

role in the process. The epidermal and the vascular 

tissues are the sources of these differentiation- 

inducing morphogens with other tissue types keying 

their differentiation frcm one or a combination of 

these two tissues. The major phytohormones are 

coordinators of long distance ccmmunication, and 

while their presence is necessary for growth and 

differentiation to occur, they do not directly 

function in the role of short distance positional 

information. 

WARMBRODT, ROBERT D. Department of Botany, The 

Ohio State University, Columbus, OH 43210. - 

Structure of the mature leaf of Pyrossia 

longifolia--an epiphytic, polypodiaceous fern 

exhibi,ting Crassulacean acid metabolism. 

The leaf of Pyrossia longifolia was examined by light 

and electron microscopy to determine the cytological 

characteristics and various interrelationships of the 

ground and vascular tissue. The succulent leaf has 

a reticulate vascular system embedded in mesophyll 

tissue that is not differentiated into distinct pali- 

sade and spongy layers. The large, isodiametric 

mesophyll cells each contain a thin, parietal layer 

of cytoplasm surrounding a large, central vacuole. 

The chloroplast-microbody ratio in the mesophyll 

cells indicates Pyrossia may be a high photorespirer 

and, thus similar in that sense to C3 plants. 

Mesophyll tissue is separated from vascular tissue by 

a tightly-arranged layer of chlorenchyma cells and an 

endodermis with Casparian strips. The walls of both 

layers of cells lack suberin lamellae. The colla- 

teral veins contain vascular parenchyma cells, sieve 

elements and tracheids in addition to a layer of 

pericycle cells. The vascular parenchyma cells, 

each 2-3 times larger in diameter than the sieve 

elements, are characterized by dense cytoplasm and 

chloroplasts which contain a peripheral reticulum. 

Parenchymatic elements are connected by plasmodesmata 

which lack neck constrictions or sphincters orsphinc- 

ter-like structures. Cytoplasmic connections between 

sieve elements and parenchymatic elements are pore- 

plasmodesmata with wall thickenings on the parenchy- 

matic-element side of the wall. The relative fre- 

quenci es of connecti ons between vari ous cel l types 

of the leaf indicate photoassimilates may move from 

the mesophyll to the site of phloem loading solely 

in the symplast or by a combinatiorn of symplast and 

apopl ast. 

WEBB, DAVID T.*, Department of Biology, Queen's 

University, Kingston, Ontario, K7L 3N6, SANDRA 

DE JESUS and MARIO NEVAREZ, Department of Biology, 

University of Puerto Rico, Rio Piedras, P.R.99031. 

- Further in vitro studies of cycad root nodu- 

lation. Seedlings of Zamia furfuraceae, Cycas 

revoluta and Encephalartos altensteinii were asep- 

tically cultured in modified White's minerals plus 

2% sucrose on 1.5% agar slants in 35 x 300 mm test 

tubes at 27C. In all cases, root nodulation did not 

occur in darkness. However, exposure to fluorescent 

light of approximately 5 klux induced root nodulation 

in all three species. With Z. furfuraceae and 

C. revoluta, light exposure caused subapical callus 

formation by secondary roots previously formed in 

darkness. This was not observed with E. alten- 

steinii. Massive calluses developed from C. revoluta 

primary roots in darkness and light, but callus for- 

mation was not as extensive in light-exposed cultures 

Similar callus formation was not observed with the 

other two species tested. Apogpotropic secondary 

roots developed at the junction of the primary root 

and cotyledonary node with E. altensteinii grown in 

darkness, but apogeotropism was not induced by light 

and was not observed in other tested species. 

WEBB, MARY ALICE* and HOWARD J. ARNOTT. 


Arlington, Arlington, TX 76019-0498. - Druse 

development in the endosperm of Vitis mustangensis. 

An understanding of crystal development as it relates to 

other developmental processes in a particular tissue is an 

essential prerequisite to comprehending any role crystal 

formation may have in cellular metabolism, in addition to 

clarifying the role of the cell in crystal formation. In 

the nutrient tissues of mature seeds crystals are often 

found within storage protein bodies, and in some such 

cases crystals are very abundant. Each cell in the mature 

endosperm of Vitis mustangensis contains either a calcium 

oxalate druse (crystal aggregate) or a large globoid com- 

posed of mineral salts of phytic acid; both forms of 

mineral deposits are found within large protein bodies, 

and the distribution of globoid cells and crystal cells 

within the endosperm appears to be random. The 

abundance of crystal cells in the tissue make it a good 

system for studying crystal development and relating 

crystal formation to the other processes involved in seed 

development. At the initiation of crystal formation the 

cell walls of the endosperm have begun to thicken, lipid 

bodies have accumulated within the cytoplasm, and the 

central vacuole has become subdivided into several 

smaller vacuoles. Large amounts of endoplasmic 

reticulum with swollen cisternae are present, and some 

accumulation of protein within vacuoles is evident. There 

is no evidence of phytin deposition at this stage of 

development. Crystal formation occurs within the 

vacuoles in association with a complex array of organic 

material, including at various stages paracrystalline 

arrays, membranes, and fibrillar structures. Some of this 

material persists and is present as a central organic core 

in the mature druse. The organic matrix associated with 

crystal formation in this system will be compared to that 

observed in other studies of crystal development in plant 

cells, as well as in certain animal systems. 

WESTERLING, 

KARIN E.*, INDIRA J. MEHTA, and PATRICK 

L. HEALEY. Department of Developmental and Cell 

Biology, University of California, Irvine, CA 

92717. - The effect of 2-(3,4-dichlorophenoxy)- 

triethylamine on resin canal morphology in 

Parthenium ar entatum, Gray

Parthenium argentatum, Gray (guayule), a north Amer- 

ican desert shrub, contains large quantities of high 

quality rubber. Unlike Hevea, P. argentatum stores 

rubber within parenchymatous cells. The first 

appearance of rubber occurs in the epithelial cells 

of the primary and secondary resin canals of six to 

eight month old plants. The morphology of these 

resin canals has been previously described. Bio- 

regulators, such as 2-(3,4-dichlorophenoxy)-triethyl- 

amine (DCPTA), are known to increase the total rubber 

content of P. argentatum. Experimental P. argentatum 

plants were treated by spraying with a solution of 

50 ppm DCPTA and 250 ppm Ortho X-77 (a wetting agent) 

while control plants were sprayed with the Ortho X-77 

only. An analysis was made of the effects of these 

treatments on resin canal morphology, including resin 

canal number and size and epithelial cell number and 

size. 

WILDER, GEORGE J.* and PHILIP B. TOMLINSON. 

Harvard Forest, Harvard University, 

- Functional and systematic-anatomical 

Petersham, 

studies 

MA. 

of 

laminae of the Cyclanthaceae. I. Epidermis. 

Cyclanthaceous laminae are normally hypostomatic and 

their abaxial epidermis tends to exhibit longitudinal 

bands either with or without stomata. In the subfamily 

Carludovicoideae bands of the abaxial epidermis 

without stomata develop over fiber bundles, abaxial 

ridges, and sometimes veins; bands of epidermal expansion 

cells, also without stomata, occur in each 

epidermis above or below adaxial and abaxial ridges, 

and over expansion tissue of the mesophyll. Stomata 

are either functional or nonfunctional. The pore of 

a functional stomate extends between inner and outer 

ledges of the guard cells, and consists of a one or 

two-chambered front cavity, back cavity, and central 

pore. Both guard cells of a stomate may be connected 

by two obvious polar perforations. Nonfunctional 

stomata exhibit collapsed guard cells with or without 

lignified walls, and sometimes also have substomatal 

chambers occluded by the abnormal enlargement of adjacent 

cells, e.g. subsidiary cells. Subsidiary 

cells and undifferentiated epidermal cells may overlap 

one another in ways that appear mechanically advantageous. 

Each stomate is typically associated 

with fo'ur subsidiary cells which may differ from undifferentiated 

epidermal cells according to position, 

shape, non-nuclear contents, nuclear size, cuticular 

ornamentation, and cell walls. In each subfamily epidermal 

cells proper may exhibit lumen papillae and 

also cuticular ornamentation (papillae, ridges). An 

epidermis sometimes has substantial dorsiventral symmetry. 

In addition, one can sometimes determine (a) 

whether a noncostal fragment of epidermis belonged to 

the abaxial or adaxial leaf surface, (b) what types of 

cells or structures it occurred over, (c) which are 

its proximal or distal ends and, hence, (d) its right 

and left sides. Systematic conclusions w'll be given. 

WILDER, GEORGE J.* and PHILIP B. TOMLINSON. 

Harvard Forest, 

01366. 

Harvard University, Petersham, MA 

- Functional and systematic-anatomical studies of 

laminae 

veins. 

of the Cyclanthaceae. II. Mesophyll and 

The mesophyll contains hypodermal cells, bundle 

sheath cells, epithelial cells of mucilage cavities 

(certain Garludovicoideae), and laticifer sheaths 

(Cyclanthus), which exhibit common features and, 

hence, are categorized together as "boundary layers" 

The remaining cells of the mesophyll between boundary 


layers comprise adaxial, abaxial, and sometimes mid- 

dle regions. Depending on the species, ordinary pa- 

renchymacells between boundary layers are either mono- 

morphic or dimorphic; where dimorphic, one of the two 

types - generally, with larger and more concentrated 

chloroplasts - is interpreted as more specialized for 

photosynthesis. Within ordinary parenchyma cells, 

tannin or tannin-like material may comprise very ela- 

borate star figures which are refractile in preserved 

material. In certain species of Carludovicoideae the 

mesophyll contains thin-walled dead cells, and pres- 

ence of these cells is of particular interest because 

of the occurrence of lysigenous intercellular spaces 

in Cyclanthus. Fibers of the mesophyll tend to differ 

from phloem fibers in ways which suggest that these 

two cell types are specialized to contribute tensile 

strength and rigidity, respectively. Raphide sacs 

and sometimes also styloid sacs occur, and what may 

superficially appear as one raphide is often com- 

pound, comprised of four or more.subunits. Veins of 

an inter-ridge area (Carludovicoideae) or between 

principal veins (Cyclanthus) are of different orders 

of diameter, and vein number increases exponentially 

in increasingly higher orders. The smallest sieve 

elements in a vein tend to be gro5uped into one or two 

poles on the adaxial side of the phloem. Systematic 

conclusions will be presented. 

WISNIEWSKI, MICHAEL*, A. LINN BOGLE and C.L. WILSON 

Department of Botany and Plant Pathology, University 

of New Hampshire, Durham, 03824. Appalachian Fruit 

Research Station, USDA, Kearneysville, WV 25430 - 

The Developmental Anatorny of Wound Response in 

Current Year Shoots of Prunus persica L. Batsch. 

The ability of peach trees to effectively compart- 

mentalize wounds may play an important role in resis- 

tance to Cytospora canker. Little information exists 

in this area for peach. Therefore, an anatomical in- 

vestigation of wound response was undertaken. Current 

year shoots of three cultivars were wounded by making 

a scratch with a fine forceps. Samples were collected 

periodically and examined using light microscopy and 

SEM. Initial wounding penetrated into the cortec and 

occasionally to the vascular cambium. Within two 

weeks, a well differentiated wound periderm was es- 

tablished from undifferentiated phloem and cortical 

cells. Normal xylem and phloem production was replac- 

ed in a wide area of the stem by parenchymatous tissue. 

These cells became hypertrophied and in some areas 

degenerated and formed gum cysts. Phellem cells pro- 

duced by the wound periderm became quickly and heavily 

suberized in contrast to normal epidermal cells. A 

region exhibiting strong autofluorescence was observ- 

ed at the radial edge of the wound periderm. Within 

four weeks, periderm formation was initiated in un- 

injured portions of the stem (i.e,, the wound peri- 

derm acted as a center for and instigated premature 

periderm development in the rest of the stem). There 

was also an accumulation of druses in the cortical 

cells of the wound area. An EDXA of these crystals 

identified the presence of calcium. No major differ- 

ences between cultivars were observed. Observations 

indicate that periderm formation occurs at a relative- 

ly fast rate compared to rates reported for other 

species and that the degree of gum cyst or gum dUCt 

formation is proportional to the severity of the wound. 

WITTLER, GEORGE H.* and JAMES D. MAUSETH. Department 

of Botany, University of Texas, Austin, TX 

78712. - The ultrastructure of developing 

ducts i n Mammill 1ari a heyderi ( Cactaceae ) 

Electron microscopy was used to investigate 

latex 

early

36 Ecological Section 

development of latex ducts in Mammillaria heyderi 

(Cactaceae). Numerous vesicles (secondary vacuoles) 

form from invaginations of the plasmalemma near sites 

of wall thinning, from endoplasmic reticulum (ER) and 

from older plastids. Dictyosomes, though they occur 

in young duct cells, do not seem to be responsible 

for the formation of vesicles. Cytoplasmic vesicles 

may contain fibrillar, globular, or crystalline materials, 

or may be devoid of any type of particulate 

matter. They may be responsible for the production 

and storage of numerous laticiferous components. Lysosomal 

materials could be stored in some vesicles 

and contribute to the degradation of the protoplast. 

Some nuclei contain condensed chromatin and are subject 

to deformation and collapse. Mitochondria and 

spherosomes are common in young duct cells but ER is 

rare. When ducts form in young tissues, plastids in 

the lumen do not produce starch grains or extensive 

membranous networks. The plastids eventually degenerate 

to become a part of the latex. If ducts form 

in older, established tissues having mature plastids, 

the plastids undergo extreme modification. 

YAKAR, NEBAHAT and OLGUN, GiKSEL. Departnint of 

Biology, University of Istanbul, Turkey. Department 

of Biology, University of Trakya, Turkey. 

- Conparative studies on megasporogenesis and developnent 

of embryo sac in Digitalis davisiana Heyw 

and Digitalis ambigua Murr. 

A new species of Digitalis which is very similar to 

Digitalis airbigua Murr., was collected by Davis in 

Antalya 1947. It was described as Digitalis davisiana 

by Heywood (1949). This new species has been studied 

morphologically and anatomically by Tozun (1961) and 

karyologically compared with D. ambigua by Yakar and 

Symposium: New Approaches to the Population 

Biology and Physiological Ecology of Plants 

INTRODUCTION 

Greater understanding of plant populations in the 

field is being achieved through the use of both new 

techniques and old techniques used in new ways. For 

example, the movement of photosynthates between old 

and new ramets, and between vegetative and reproductive 

tissue can be examined in the field using 

Carbon-14 labeling techniques, and in the lab using 

a non-destructive procedure with gamma-emitting Carbon 

-11. Greater ability to determine the genetic structure 

of populations can be achieved using detailed 

analysis of electrophoretic variation to determine 

the paternal parent of each seed and using distinct 

radionuclide markers to determine the paternal parent 

of seedlings. Such approaches can be combined with 

a greater ability to quantify within population variation 

in such characters as plant secondary compounds 

and even actual DNA sequences. In this way the genetic 

basis of resource allocation to specific adaptations 

can be investigated at the population level 

in the field. 

Organized by Richard B. Primack, Boston Univeristy, 

Boston, MA. 

ECOLOGICAL SECTION 

TozUn (1966). The present investigation was undertak- 

en to elucidate the meiotic division in megaspor mroth- 

er cells and development of embryo sac of D. davisiana 

and to compare it with D. ambigua. 

YOU, RUILIN and WILLIAM A. JENSEN*. Department of 

Botany, University of California, Berkeley, CA 

94720. - Ultrastructural observations of the 

mature megagametophyte and fertilization in wheat. 

The mature embryo sac of wheat contains an egg 

apparatus composed of an egg cell and two synergids 

at the micropylar end, a central cell with two large 

polar nuclei in the middle, and a mass of 20 to 30 

antipodals at the chalazal end. A comparison was 

made of the ultrastructural features of the various 

cells of the embryo sac. The cells of the egg appa- 

ratus have walls that extend half-way along the cells 

starting from the micropylar end. Both synergids 

appear to be degenerating before pollination. The 

pollen tube enters one synergid through -the filiform 

apparatus from the micropyle. The penetration and 

discharge of the pollen tube causes the further 

degeneration of that synergid. The second synergid 

does not change further in appearance following the 

penetration of the first by the pollen tube. Thus, 

the two synergid cytoplasms look different after 

pollen tube discharge. Half an hour after pollina- 

tion at 20-25?C, two male nuclei are seen in the 

cytoplasm of the egg and the central cell. At about 

one hour after pollination one sperm has made contact 

with the egg nucleus, while the other sperm is fusing 

with one of the polar nuclei. The phenomena of both 

synergids starting degeneration before pollination 

and the occurrence of the large mitochondria with 

complicated internal organization in the antipodals 

will be discussed. 

ELLSTRAND, NORMAN C. Department of Botany and 

Plant Sciences, University of California, 

Riverside, CA 92521. - Paternal fitness and gene 

flow measurements using electrophoretic analysis. 

Although gene flow can be an important evolutionary 

force, realized gene flow studies of natural plant 

populations remain few. Electrophoretic analysis 

of enough polymorphic loci scored from parents and 

progeny permits unambiguous identification of paternal 

parents and thus allows precise measurement 

of gene flow patterns. In particular, the following 

correlates of paternity can be examined: (1) 

whether nearest-neighbor pollen flow is extensive; 

(2) what role genetic relatedness plays in determining 

paternal success; (3) whether there are 

within-season changes in the successful paternal 

gene pool; (4) whether hermaphroditic plants actually 

have equal fitness as male and female parents; 

and (5) how many fathers sire the seed set 

within fruits and over the total seed set of a 

given individual. Preliminary data from such 

"plant parenthood" studies will be presented. 

Lincoln, David E. Department of Biology, 

University of South Carolina, Columbia SC 29208. 

-Individual variation of plant secondary compounds

in relation to insect herbivory and carbon- 

allocation. 

Carbon allocation and energy budgets are useful 

concepts *for predicting and examining the responses 

of organisms to environmental resources and 

stresses. Ecological processes are potentially 

amenable to this approach assuming many organisms 

have limited carbon or energy incomes and are 

therefore subject to at least some constraints in 

the allocation of these incomes. The allocation 

of plant resources to defense against herbivores 

can be approached by focussing on variation of 

secondary chemical production. Recent instrumen- 

tation improvements, particularly in gas and high 

pressure liquid chromatography, have facilitated 

a shift from pre,ence/absence information toward 

quantitative measurement of leaf secondary chemi- 

cals. Variation in production of such chemicals 

within and among plants is examined in regard to 

ecological constraints which may influence patterns 

of carbon allocation. These include conditions 

which may: (a) directly influence chemical pro- 

duction, e.g. differing levels of herbivory, (b) 

influence plant carbon income, e.g. physical or 

chemical limitations on photosynthesis, or (c) 

affect both budgetary components, such as leaf 

nitrogen content. The implications of these 

variations will be examined within a plant-centered 

consideration of current models of the "cost" of 

plant antiherbivore chemicals. 

PITELKA, LOUIS F.* and JEFFREY W. ASHMUN, Bates 

College, Lewiston, Maine 04240. -The use of 

carbon-14 and other radioisotopes to study 

resource allocation in field populations. 

C-14 and other radioisotopes have long been employed 

to follow the movement of photosynthate or other 

metabolites. Experiments using such tracers can be 

conducted quite easily in the field on natural 

populations. These techniques represent a useful 

tool for addressing problems of interest to 

population biologists. For instance, C-14 may be 

used to reveal spatial or temporal patterns of 

resource allocation that are difficult to detect with 

biomass or calorific analyses. By labelling plants 

at different times in a season or by harvesting 

plants at increasing intervals after labelling, 

seasonal patterns of resource allocation and 

reallocation can be analyzed. Especially in 

perennials, the role of stored reserves vs. current 

assimilation in supporting new growth or 

reproduction may be compared. A more specific use 

of tracers is seen in studies of connections between 

plants. In clonal plants, C-14 can be used to assess 

the degree to which persistent connections remain 

active and connected ramets function as single 

physiological units. Functional connections may 

affect how individual ramets respond to competition 

and herbivory and how they accomodate the demands and 

risks of reproduction. The use of isotopes other 

than C-14 may show that the movement of other 

resources differs from that of photosynthate. 

Connections can also exist among unrelated plants 

(same or different species) as a result of root 

grafts or fungal associations. Radioistopes reveal 

how these function. This in turn should increase 

our understanding of the ecologically important 

costs and benefits of such connections. 

PRIMACK, RICHARD B. * and CHARLES K. LEVY, Biology 

Department, Boston University, Boston, MA 02215. 

Radionuclide labeling of seeds to assess fitness 

in plants. 

Ecological Section 37 

One of the primaty problems in estimating individual 

fitness in plant populations has been the difficulty 

of following seeds from one generation to the next. 

Individual adult plants can be characterized for 

traits which may be related to fitness, but we have 

little ability to identify individuals which actually 

leave more surviving offspring into the next genera- 

tion. In this project, we are exploring techniques 

for tagging seeds with selected combinations of 

gamma-emitting radionuclides (60Co, 137Cs, 54Mn, 

etc.). These labels are not harmful to either the 

plants or the investigators due to the extreme sensi- 

tivity of the crystal scintillation equipment. Our 

preliminary studies with radishes, beans, Impatiens, 

Bidens, and Polygonum have shown that these labels 

can be injected into the stem of the adult plant and 

are rapidly taken up by the developing seeds. In the 

lab, the labels are present in the cotyledons of the 

young seedlings. Following dispersal and germinatiorn 

the maternal parent of the seedling can potentially 

be identified in the field without killing the seed- 

ling by sampling a small piece of the cotyledon. 

This technique will potentially allow us to determine 

the heritability of life history characters under 

field conditions, changes in genotype frequency with 

time, the dispersal and distribution of seedling 

families within the population, and the longevity of 

seeds in the soil. The fate of introduced or novel 

genotypes in a population can be studied experimental- 

ly by adding labeled seeds to a population. We are 

determining whether this technique can be used to 

label pollen of different plants to determine the 

male parent of a seed. 

SCHAAL, BARBARA A. Department of Biology, Washington 

University, St. Louis MO 63130. 

Variation of DNA seguences in plant populations. 

Genetic variation among individuals is essential for 

the evolutionary process, yet absolute levels of 

variation are known for very few species. The development 

of nucleic acid technologies, such as restriction 

fragment analyses and hybridization to cloned 

probes, has allowed the analysis of variation in 

specific DNA sequences. Analysis of the DNA sequences 

which code for ribosomal RNA (rDNA) show variation 

among individuals for DNA nucleotide sequence, variation 

in the length of the rDNA sequence, and variation 

for total gene copy number. Variability 

viduals within species is predominantly 

among indiin 

the nontranscribed 

spacer region of rDNA. Variation among 

taxa occurs in the evolutionarily conservative 17 S 

and 26 S coding regions. These molecular data are 

providing precise measures of variation within and 

among plant species. 

STRAIN, B.R.*l, J.D. GOESCHL2, Y. FARES?-2 C.E. 

MAGNUSON2, C.E. NELSON3, C.H. JAEGER1, and E.G. 

BILPUCH3. lDepartment of Botany, Duke University, 

Durham, NC 27706, 2Biosystems Research Division, 

Texas A&M University, College Station, TX 77843, 

and 3Department of Physics, Duke University, 

Durham, NC 27706. - Use of carbon-li for 

continuous non-destructive monitoring of photosynthate 

movement. 

A system has been developed at the Duke University 

Phytotron which allows the study of carbon flow 

dynamics in plants without destructive sampling of 

tissues. The system utilizes the short half life 

(20.3 min) carbon-ll isotope continuously supplied to 

the plants as 11CO2. The isotope is produced continuously 

with a dedicated 4 MeV Van de Graaff 

accelerator in the nearby ( < 100) m) physics department.. 

As a tracer, hGc has several advantages. lIt


decays by positron (O+) emission followed by 

positron-electron annihilation with the emission of 

two oppositely directed gamma rays. These y-rays 

have sufficient energy to be detected through several 

cm of tissue and/or soil. This makes it possible to 

perform several sequential experiments on the same 

plant because no destructive tissue sampling is 

required. The system also includes infrared analyzers 

and dew point analyzers so the simulataneous measure- 

ment of 12CO2 and water vapor exchange may be made 

for comparison with IIC net photosynthesis measure- 

ments. Comparative studies of drought stress and C02 

enrichment on Abutilon theophrasti and Gossypium 

hirsutum suggest basically different phloem transport 

systems in these two genera of the Malvaceae. Effects 

of environmental factors on carbon allocation and 

flux rates are currently being examined in C3 and C4 

plants by several other scientists. The facility is 

part of the analytical equipment of the Duke Phytotron 

and thus is available to all scientists using the 

Phytotron. 

Symposium: Size Hierarchies in Plant 

Populations 

INTRODUCTION 

Size frequency distributions, which are usually size 

hierarchies, are a fundamental but little understood 

aspect of plant population ecology and genetics. It 

has become apparent in the last few years that mean 

plant performance is a very crude measure of popula- 

tion behavior. By contrast, a Darwinian view of the 

population puts more emphasis on the individual, and 

plant-to-plant variation, which may be very great, is 

of much interest. There is much evidence that, with- 

in a population, plant size is related to fitness, and 

in natural population the few largest individuals may 

be responsible for virtually all the population's 

reproduction. When allelic frequencies among the 

large individuals are different from those of the pop- 

ulation as a whole, evolutionary change will occur. 

Size differences may be caused directly or through 

variation in growth rates by factors such as age 

differences, genetic variation, heterogeniety of re- 

sources, interference, or the effects of herbivores, 

parasites or pathogens. Which of these possible 

factors are important in determining size differences 

is unknown. 

This symposium will explore the causes and conse- 

quences of size hierarchies through field, experimen- 

tal and theoretical studies. 

Organized by Jacob Weiner, Swarthmore College, Swarth- 

more, PA. 

DOLAN, REBECCA WILCOX. Department of Botany, 

University of Georgia, Athens, GA 30602 and 

Savannah River Ecology Laboratory, P.O. Drawer E, 

Aiken, SC 29801 - Size hierarchies in Ludwigia 

leptocarpa (Onagraceae). 

Ludwigia leptocarpa, an annual herb of stream banks 

in South Carolina, developed a nearly log-normal 

distribution of individual plant biomass during the 

1981 growing season. Fecundity was highly correlated 

with plant size (r2=0.89) so that a few large plants 

produced most of the seeds (5% of plants yielded 39% 

of the seeds). Field observations documented the 

development of a dominance hierarchy through time 

and the relative contributions of large and small 

plants to population maintenance. Field and green- 

house studies showed that size hierarchies are not 

a direct result of hierarchies in seed size and that 

early germination does not assure large adult size. 

Common garden studies showed no difference in growth 

rate of offspring from large and small plants. 

These data suggest that size hierarchies in Ludwigia 

leptocarpa are largely the result of responses to 

microhabitat differences and do not represent a 

process of evolutionary importance. 

HUSTOI, MICHAEL A. Division of Biological 

Sciences, University of Michigan, Ann Arbor, MI 

48109 

- The effect of fertilization on size distributions 

of annual plants in a plowed oldfield. 

Manipulation of productivity by fertilization has a 

predictable effect on the community structure of 

herbaceous camranities, but less is known about the 

effect of such manipulation on the population struc- 

ture of the component species. Size distributions 

were determined for populations of 4 species of an- 

nual weeds growing in fertilized and unfertilized 

plots at the University of Michigan Botanical 

Garden. The study plots were roto-tilled to a depth 

of 6 inches in April 1981 and April 1982, and 2 of 4 

10 x 10 m areas were fertilized with 164 kg/ha NPK 

26:3:3 at the beginning of each growing season. In 

SFptember 1982 a total of 128 regularly spaced 0.25 

m quadrats were clipped, and dry weight determined 

by species. Height and bicanass were recorded for 

each individual of Acalypha rhanboidea, Ambrosia 

artemesiifolia, Amaranthus powellii, and Chnpodium 

album. Low productvitysi-tes yve more even size 

distEibutions of individual populations, as well as 

mre even distributions of biomass per species. 

RABINOWITZ, DEBORAH. Section of Ecology and 

Systematics, Cornell University, Ithaca, 

NY 14853-0239. 

-Size variation in crop monocultures. 

Plant form and growth patterns influence how plants 

interact in monocultures. For a diversity of crop 

architectures (grains and vegetable crops), we 

investigated whether leaf arrays and growth rates 

were important in determining dominance and 

suppression and the distribution of individual sizes. 

How size of individuals determines plant-to-plant 

variance in crop yield was investigated as well. 

WEINER, JACOB. Department of Biology 

Swarthmore College, Swarthmore, PA 19081 

- Size hierarchies in experimental plant 

populations. 

Greenhouse experiments were conducted to address 

some of the causes of size hierarchies (size 

inequalities) in plant populations. There is 

controversy over whether or not competition increases 

the degree of hierarchy within a population, i.e. 

whether dominance and suppression result from 

interference between individual plants. I 

performed a series of greenhouse experiments on 

populations of Trifolium incarantum and Lolium 

multiflorum to study the effects of several 

variables on size frequency distributions. The 

following hypotheses were observed to be consistent 

with the data: 

1) Size inequality increases with increasing density. 

2) Size inequality increases with increasing 

productivity. 

3) Size inequality is lower when plants are sown 

in a uniform pattern than when sown in a random 

pattern.

4) In mixtures, the competitively superior species 

shows a relatively low degree of inequality, while 

the competitively inferior species shows high 

inequality. 

The results support the dominance/suppression 

model of plant competition. 

Symposium: The Mire - Wetland Ecosystem 

INTRODUCTION 

Wetland and mire ecosystems possess a unique set of 

characteristics that differentiate these systems from 

both terrestrial and aquatic habitats. The abundant 

research that has been done in Europe in these eco- 

systems is in marked contrast to the state of our 

knowledge in North America. However, in the past 

decade or so, significant work has been completed in 

the United States and Canada. This symposium hopes 

to examine some of this recent research and present 

the status of our knowledge of these ecosystems. 

Organized by Dale H. Vitt, University of Alberta, 

Edmonton, Alberta and Bruce Roberts, Canadian Forestry 

Service, St. John's Newfoundland. 

ANDRUS, RICHARD E. Department of Biological 

Sciences, State University of New York at 

Binghamton, N.Y. 13901. 

- The ecology of Sphagnum. 

Sphagnum species are ecologically unusual and prom- 

inent wetland plants with xerophytic adaptations 

and succession-directing acidification capabilities. 

Species are differentiated along environment gra- 

dients of pH, cation concentrations, hummock and 

hollow, wet vs. dry, shade vs. sun, coastal vs. in- 

land and cold vs. warm. The known factors respon- 

sible for gradient differentiation include cation 

exchange capacity, desiccation tolerance, desicca- 

tion resistance, water-holding capacity, drying 

rates and photosynthetic response at differing water 

contents. Small-scale distribution of Sphagnum 

species on ombrotrophic sites can be partially ex- 

plained but for minerotrophic sites, where acid 

precipitation influence is greatest, less is known. 

BAYLEY, SUZANNE. Freshwater Institute, 

501 University Crescent, Winnipeg, Manitoba. 

R3T 2N6 

- Comparisons of nutrient relationships in 

freshwater wetlands from Canada to Florida. 

Nitrogen and phosphorus dynamics in southern 

swamp forests and fresh water marshes are compared 

to northern bogs, fens, and marshes. Latitudinal 

differences in nitrogen and phosphorus content of 

vegetation, nutrient concentrations of surface 

and pore water, and annual nutrient uptake are 

not apparent in the data reviewed. Substrate and 

hydrologic regimes appear to be more important. 

Vegetation on organic substrates contains less 

nitrogen and phosphorus in the above ground 

biomass (Wigham and Bayley 1978). Cypress 

wetlands in higher water flow contain higher 

concentrations of phosphorus in above ground 

biomass (Brown 1981). Other wetlands appear to 

follow the same trend. The ability of a wetland 

to retain added nutrients depends upon the 

hydrologic regime and organic substrate. 


CARTER, VIRGINIA U.S. Geological Survey, 431 

National Center, Reston, VA 22092 - Wetlands of 

the United States- ecology, hydrology, and research 

needs. 

The wetlands of United States can be subdivided into 

classes, subclasses, and dominance types on the basis 

of vegetation, hydrology and soils using the "Classi- 

fication of Wetlands and Deep Water Habitats" by 

Cowardin et al. (1979). There is a tremendous 

diversity in wetland types and wetland vegetation in 

the United States, caused primarily by regional 

topographic and climatic differences. Wetland 

hydrology, a primary driving force influencing 

wetland ecology and wetland development and persis- 

tence, is as yet poorly understood. The interaction 

between ground water and surface water, and the 

discharge-recharge relationships in wetlands 

influence water quality and nutrient budgets as well 

as vegetative composition. Anthropogenic influences, 

such as construction of drainage canals, diversions, 

storage areas and industrial facilitites, or mining 

of peat may have unforseen hydrologic consequences 

because of our lack of knowledge of water movement 

and water budgets. Expanded research and basic data 

collection are needed to manage and protect wetlands 

effectively. 

DAMMAN, ANTONI W.H. Ecology Section, Biological 

Sciences Group, University of Connecticut, 

Storrs, CT 06268. 

- Ecological processes in ombrogenic peat bogs 

Ombrogenic peat bogs differ from soligenic and 

topogenic peatlands in their hydrology and associated 

differences in water chemistry, organic matter 

accumulation and vegetation. The hydraulic potential 

is positive in most of the raised peat mass, and 

water flow is primarily through the relatively 

undecompsed surface peat. The extreme nutrient- 

deficiency of ombrotrophic peat and the growth of 

the Sphagnum carpet create conditions for release 

and accumulation of elements which are fundamentally 

different from those on minerotrophic sites. In 

ombrotrophic parts of these peatlands, productivity 

affects peat accumulation, but on minerotrophic 

sites decomposition overrides differences in 

productivity and peat does not accumulate to any 

significant degree above the water level. Potassium, 

and to a lesser degree Ca, concentrations show 

seasonal fluctuations in the drainage water with 

high concentrations in spring and autumn, and 

concentrations far below that of the precipitation 

during the summer. Na and Mg concentrations remain 

5-10 times that of the precipitation. The chemistry 

of bog pool water depends on the topographical 

position within the bog; it differs least from 

rain water in the pools of the center or highest 

part of bogs in oceanic regions. 

GORHAM, EVILLE. Department of Ecology & Behavioral 

Biology, University of Minnesota, Minneapolis, 

MN 55455-0302. 

- The biogeochemistry of Sphagnum bogs. 

The following topics are discussed briefly from a 

historical perspective and with modern examples; fac- 

tors controlling peat accumulation and paludification 

(waterlogging, nutrient limitation, roles of climate 

and topography), hydrological and chemical differen- 

tiation of bog from fen plant communities (surface 

waters and peats, peat profiles, plants), the acidity 

of bog waters (sources, ion-balances, sensitivity to


acid rain), atmospheric deposition (sea salt, soil 

dust, pollutants--radioactive fallout, heavy metals, 

synthetic organics), element mobility (solubility, 

plant uptake, gaseous cycles), retention of elements 

(biophile, lithophile, pollutant), chemical budgets 

(inputs, storages, outputs), and organic geochemistry 

(labile and refractory molecules, the ion-exchange 

complex. 

The focus is upon ombrotrophic Sphagnum bogs with 

surfaces receiving only atmospheric precipitation, 

but comparisons will be made with minerotrophic fens 

receiving water that has percolated through mineral 

soil. 

HORTON, DIANA G. Department of Botany, University 

of Alberta, Edmonton, Alberta T6G 2E9 

- Applicability of the Scandinavian Concept to Fen 

Vegetation in North America. 

According to the classical Scandinavian concept, fen 

vegetation can be subdivided into three types: 

poor, intermediate and rich, with each type defined 

by the occurrence of a number of indicator species. 

The environmental factor that appears to correlate 

most closely with this variation in the vegetation 

between the different types of fens is water 

chemistry. A survey of the fen vegetation that has 

been studied in North America reveals that many of 

the species considered to be indicators of particu- 

lar conditions, with respect to water chemistry, in 

Fennoscandia reflect similar habitat conditions in 

North America. This is particularly true of the 

bryophytic component of the vegetation. Therefore, 

the Scandinavian concept appears to be an appropri- 

ate approach to the characterization of fen vegeta- 

tion in North America, at least with respect to rich 

and poor fens. 

JEGLUM, JOHN K. Canadian Forestry Service, Great 

Lakes Forest Research Centre, Box 490, Sault Ste. 

Marie, Ontario, P6A 5M7, Canada. 

- The swamp/treed bog sequence in Ontario's Clay 

Belt: Classification, ecology, and management for 

forestry. 

A program of forest ecosystem classification was 

developed for Ontario's Clay Belt to provide opera- 

tional working groups for forest management purposes. 

A high proportion of the merchantable black spruce 

forests in the Clay Belt are on organic soils. A 

sample of 120 forested stands on organic soils was 

described for vegetation soils and other site 

features and analyzed using classification, ordina- 

tion and discriminant programs. Four operational 

groups were recognized -- 'herb-rich alder', 'herb- 

poor alder', 'Labrador-tea', and 'leather'leaf'. The 

latter encompasses minerotrophic and ombrotrophic 

conditions. The above sequence related to decreasing 

pits and channels, decreasing pH and calcium of 

ground water and peat, decreasing peat humification, 

and decreasing tree growth. The types are character- 

ized in terms of vegetation and site features. Some 

aspects of peatland development, including paludi- 

fication, are discussed for the groups. Current 

forest management practices, prescriptions, and 

research needs are presented. 

MALMER, NILS, Department of Plant Ecology, 

Lund University, Ostra Vallgatan 14, S-223 61 Lund 

Sweden - Vegetational gradients in relation to 

environmental conditions in NW European mires. 

Floristically characterized gradients related to (1) 

wetness of micro-sites, (2) marginal compared to 

central areas, (3) ombrotrophic compared to different 

kinds of minerotrophic areas ("poor and rich mires"), 

and (4) distance from sea can be recognized in all 

mire vegetation in NW Europe. Along all gradients 

variation is found in (1) course of water level, (2) 

origin and flow of water and (3) supply of minerals, 

conditions influencing the decay processes and 

therefore also the peat accumulation rate, the pH, 

the mineral nutrient supply, and the productivity. 

The differences between marginal and open areas might 

result from differences in nutrient supply (N,P,K) 

while the differences between "poor and rich mires" 

more result from differences in pH. In Sphagnum- 

-dominated vegetation most floristic variation might 

result from effects of differences in peat accumu- 

lation rate. Other climatic conditions than supply 

of minerals are most important in establishing 

floristic differences related to distance from sea. 

ROBERTS, B.A. and A.W. ROBERTSON. Nfld. Forest 

Res. Centre, Canadian Forestry Service, P.O. Box 

6028, St. John's, Nfld., ALC 5X8. 

- Atlantic salt marshes 

This paper reviews current research on the Atlantic 

salt marshes of Eastern Canada. Specifically, this 

paper discusses salt marshes in the transition zone 

between the Subarctic and the Boreal phytogeographic 

regions. These salt marshes are also the northern 

limit of many temperate species partly due to 

anthropogenic influences. The floristics, the 

habitats and biophysical aspects of the Atlantic 

marshes are described. Aspects relating to anthro- 

pogenic influences on the Atlantic marshes are 

discussed in the context of archeology, contemporary 

rural settlement and vulnerability to offshore oil 

development. Guidelines for environment management, 

protection and rehabilitation research are proposed. 

Such guidelines are deemed important since more than 

half the 33 000 ha of salt marshes in Nova Scotia 

have been dyked for agriculture. Most of the salt 

marsh habitats in Newfoundland have a high degree 

of domestic grazing even though the marshes are 

small in size and rare in occurrence. The least 

disturbed in terms of domestic use are the 

Labrador salt marshes which although grazed by 

migratory ducks and geese have not yet been influ- 

enced by man's activities. In addition, the 

Labrador salt marshes are discussed and compared 

to the northern marshes of Arctic Canada in terms 

of their ecology and development. 

SHAY, JENNIFER M. Department of Botany, 

University of Manitoba, Winnipeg, Manitoba, 

Canada R3T 2N2 

- Prairie marshes in Western Canada. 

Freshwater marshes are dynamic ecosystems that res- 

pond to environmental changes such as periodic water 

level fluctuations. Delta Marsh at the south end of 

Lake Manitoba covers 15,000 ha with open water, 

channels and emergent vegetation. Dominant macro- 

phytes include the submerged aquatics Potamogeton 

pectinatus, P. vaginatus and Myriophyllum exalbescens; 

the emergents Phragmites australis, Typha spp. and 

Scirpus acutus; and the wet meadow species Scolochloa 

festucacea and Carex atherodes. The last natural 

high water cycle peaked in 1955 inundating and 

killing thousands of ha of vegetation. Recolonisa- 

tion was monitored for four years as water levels 

fell, by which time most areas had returned to emerg-

ent dominants. Monitoring during the ensuing 20 

years recorded the spread of Typha, changes in 

density and productivity of other dominants, and 

minor shifts in understory species. Analysis of 

alterations in species composition can be used to 

predict vegetation responses after flooding in 

similar marshes. Phragmites, Typha, Scirpus and 

Scolochloa life cycle characteristics and biomass 

have been monitored in a number of sites. Variations 

between sites and years will be compared with data 

from a transect from lat 51?N to lat 56?N. 

VAN DER VALK, ARNOLD G. Department of Botany, 

Iowa State University, Ames, IA 50011. 

- Vegetation dynamics in freshwater wetlands. 

Vegetation change in freshwater wetlands will be 

reviewed as well as theories put forth to explain 

it. This review will focus on two basic questions: 

(1) What are the mechanisms that enable the 

establishment and persistence of wetland vegetation? 

(2) What are the mechanisms that cause the com- 

position and structure of wetland vegetation to 

change? A new model is presented in which all 

vegetation change is due to one of three phenomena 

or a combination of them: Gleasonian succession, 

maturation, and fluctuation. These three phenomena 

are defined and then illustrated using data from 

prairie glacial marshes. 


AARSSEN* LONNIE W. & ROY TURKINGTONo Botany Dept., 

University 

V6T 2B1. 

of British Columbia, Vancouver, B.C. 

- Temporal vegetation patterns in three different 

aged pastures. 

Three adjacent pastures (planted in 1977, 1958 and 

1939) on a farm in the lower Fraser Valley of British 

Columbia were surveyed periodically over a 3 year 

period. In each survey, species cover was recorded 

in quadrats and contact sampling was used to investigate 

temporal patterns of fine-scale association 

between species. Ordination of time-series percentage 

cover surveys showed a trend of increasing community 

constancy in older pastures and suggested that 

the three communities have a developmental relationship. 

Soil analyses showed little correlation with 

species cover and the fewest correlations in the 

oldest pasture. Interspecific associations in 

younger communities were predominantly temporary in 

nature while older communities had more associations 

which persisted essentially unchanged. This data 

formed the basis of a qualitative model of pasture 

community evolution which attributes within-community 

temporal changes to the selective forces accruing 

from biotic interactions. 

ATKINS, TREVOR A.** Dept. of Botany, U. of Manitoba, 

Winnipeg, Manitoba, R3T 2N2; PETER F. LEE, Dept. of 

Biology, Lakehead U., Thunder Bay, Ontario, P7B 5E1; 

JOHN M. STEWART, Dept. of Botany, U. of Manitoba, 

Winnipeg, Manitoba, R3T 2N2. 

-Environmental interactions influencing the growth 

and development of Zizania aquatica. 

Two sites on Lake of the Woods, Ontario were monitored 


bi-weekly in the summer of 1982. Wild rice growth 

(density, biomass, phenophase) and tissue nutrition (9 

elements) were measured through sampling in randomized 

complete block experiments. Water depth was used as a 

blocking factor in both sites: One site also included 

blocking on the presence of lily pad (Nuphar) competit- 

ion. The physical environments of the two sites were 

monitored for water depth, water column temperature and 

dissolved oxygen concentration profiles; and soils for 

pH, conductivity, bulk density and nutrient regime. 

Biomass, density, and nutrient contents of competing 

macrophytes were also measured. The growth and devel- 

opment of the wild rice population was then related 

to its physical environment through multi-variate 

analysis. Growth was found to be influenced by enviro- 

mental factors common to other studies. The previously 

unexplored interactions amongst variables yielded 

inLsight into the growth and development of wild rice. 

Interactions with oxygen are of significant interest. 

BARNES, FAIRLEY J.*, and GARY L CUNNINGHAM. Dept. 

Biology, New Mexico State University, Las Cruces, 

NM 88003. - Water status of dominant species in 

pinyon-juniper habitat types. 

Pinus edulis and Juniperus monosperma have overlapping 

distributions in the pinyon-juniper woodland of 

northern New Mexico. Forty sites representing the 

range of pinyon-juniper habitats in the Jemez 

Mountains were analyzed using vegetative and physical 

site characteristics. Three habitat types (HT) were 

distinguishable primarily on the densities of mature 

and seedling P. edulis and J. monosperma, and 

secondarily on the presence of specific perennial 

grasses. Sites within each HT were ranked using the 

same criteria and six sites selected to form a 

presumptive moisture gradient characteristic of the 

woodland. Predawn leaf water potentials of P. edulis 

and J. monosperma did not vary significantly among 

the sites. This may indicate that these dominant 

trees are occupying microsites of favorable moisture 

and that their densities within the various HT's are 

a reflection of the availability of such microsites. 

BIGLEY, RICHARD E. and PAUL G. HARRISON*. Depart- 

ment of Botany, University of British Columbia, 

Vancouver, B.C., Canada V6T 2B1. - The population 

biology of two intertidal seagrasses, Zostera 

japonica and Ruppia maritima, at Roberts Bank, 

British Columbia. 

Vegetative and flowering components of co-occurring 

intertidal populations of Zostera japonica Ascherson 

and Graebner (a recent introduction) and Ruppia 

maritima L. s.l. (more commonly found in inland 

brackish water) were studied in southwestern British 

Columbia. Results from one year of repeated mapping 

and examination of shoots in permanent plots on a 

tidal gradient showed that shoot flux, age structure, 

survivorship, growth of leaves and rhizomes, and seed 

production all were affected by the amount of expos- 

ure to the air. Plots having the greatest exposure 

had fewer shoots (of both species), a greater percent 

of shoots flowering early in the season, and lower 

seed production than plots with less exposure. The 

length of the life cycle of R. maritima was the same 

regardless of differences in exposure, while plants 

of Z. japonica subject to the longest exposure to the 

air initiated and ended flowering and entered a qui- 

escent overwintering state earlier than plants lower 

in the intertidal zone.


DOUGHERTY, KEVIN W.* and JOHN L. VANKAT. Department 

of Botany, Miami University, Oxford, Ohio 

45056. - Soil properties and community distributions 

on serpentine areas of Pennsylvania and 

Maryland. 

Serpentine 

of ridges 

outcrops occur as a discontinuous series 

in southeastern Pennsylvania and northern 

Maryland. Soils derived from this ultra-basic metamorphic 

material support unusual floras and distinctive 

plant communities. Several hypotheses based on 

the physical and chemical properties of these soils 

have been offered to account for the distribution and 

diversity of plant communities on these areas. To 

test these hypotheses, soil samples and vegetation 

data were collected from eight localities representing 

the three major serpentine ridges in the eastern 

United States. Soil cores were subdivided into five 

depth increments and analyzed for selected physical 

and chemical properties. Classification and ordination 

of vegetation data from 67 releves were performed 

using the TWINSPAN, DECORANA and ORDIFLEX computer 

programs. Classification procedures have tentatively 

identified four grassland and three forest community 

types. Preliminary results indicate correlations 

between ordination axes and subsoil pH, soil depth 

and organic phosphorous concentrations. 

ELLIS, BARBARA A. Department of Botany, 

San Diego State UJniversity, San Diego, CA 92182 

-Seedling mortality and reestablishment in an 

earlv post-fire chaparral conmunity 

Seed ling mortality of two major chaparral shrub 

species was assessed in the first year following 

fire. Survival of 3-10% was observed after the first 

growing season. Excavation of seedlings revealed a 

range of root to shoot ratios of 1.0-1.2 in six monthold 

seedlings and 0.3-0.5 in one year-old seedlings. 

In the first 6 months, Ceanothus greggii produced 

sparsely branched seedling roots about 80 mm long, 

while Adenostoma fasciculatum seedling roots were 

somewhat shorter with profuse branching in the upper 

50 mm of their extension. By the end of the first 

growing season the seedling root of both species 

ranged from 220-260 mm in length. Competition between 

A. fasciculatum stump sprouts and C. greggii 

seedlings was observed. Removal of stump sprouts 

significantly increased C. greggii seedling survival. 

StRECIU, E. ANIN* and PURDOLPH CURRAH. Devonian 

Botanic Garden, University of Alberta, Edmonton 

Alberta. T6G 2E1. 

- Germination procedures for some prairie wildflowers 

native to Alberta. 

Revegetating disturbed areas in the prairies with 

native plant communities requires baseline data on 

propagation of component species. During a 3 year 

study to collect these data, 46 wildflower species, 

representing 13 families, were examined with respect 

to their germination characteristics before and 

after pretreatments. For 19 species (largely 

Compositae), germination increased significantly 

following stratification with Thermopsis rhombifolia 

and Allium textile requiring mechanical scarification 

prior to stratification. Mechanical scarification 

alone increased germination of 8 species of Leguminosae. 

The remaining 20 species either germinated 

well without pretreatment or showed no appreciable 

effect. Of this latter group Lithospermum ruderale, 

Musineon divaricatum var. hookeri, Opuntia polyacantha 

and Zizia aptera germinated less than 10% regardless 

of technique used. 

UNO, GORDON E. Botany-Microbiology Department, 

University of Oklahoma, Norman, OK 73019.- Buffalo 

wallows: 

grasslands. 

habitats for weeds and wetland species in 

Oklahoma buffalo wallows are inhabited by two distinctly 

different assemblages of plant species every 

year. In the fall, a collection of winter annual 

weeds dominates, reproducing quickly in the spring. 

After spring rains fill the wallows, a collection of 

wetland species dominates whose flowering-fruiting 

season lasts through the summer. The weedy species 

are mostly small self-pollinating plants, with inconspicuous 

flowers, low pollen/ovule ratios, and small 

seeds. The wetland species are predominately outcrossing 

plants with showy flowers or inflorescences, 

and have relatively high pollen/ovule ratios and 

large seeds. Soil cores taken in the fall and early 

summer, 1982, differ tremendously in seed bank composition, 

and the seeds have different germination 

requirements. It is hypothesized that buffalo wallows 

have served as sites for the introduction of 

weeds and weedy species into the plains and have 

served as safe sites for plant species that are restricted 

to wet habitats. 


AARSSEN, LONNIE W. Biology Dept., Queen's 

University, Kingston, Ontario, Canada, K7L 3N6. 

- Two types of combining ability in plants: 

Alternative evolutionary mechanisms of coexistence. 

Recent studies suggest that selection in response to 

competition and other neighbour interactions (e.g. 

beneficence) may result in two alternative types of 

combining ability in plants: 1) ecological combining 

ability (niche differentiation) and 2) competitive 

combining ability (balanced competitive abilities). 

Selection for ecological combining ability implies 

an increase in total yield of a species mixture. 

Selection for competitive combining ability also 

implies an increased yield but only for the inferior 

component of the mixture; the superior component 

declines in yield so that total yield is unaffected. 

Competitive combining ability is a special type of 

combining ability which takes account of the varia- 

bility which may occur in the relative contribution 

of the two components and is a reflection of their 

potential to contribute equally to the total yield. 

Both types of selection for combining ability are 

likely to operate in concert in nature. Competitive 

combining ability however has a special relevance to 

plants where frequently coexistence is incompletely 

explained by ecological combining ability. 

AARSSEN, LONNIE, W. & ROY TURKINGTON* Botany Dept., 

University of British Columbia, Vancouver, B.C. 

V6T 2B1. 

- Intraspecific diversity in natural populations of 

Trifolium repens, Lotium perenne and Holcus Zanatus 

from four different ages of pastures. 

An investigation of the range of diversity in single 

populations of TYifoliwn repens, Lotium perenne and 

Hotcus Zanatus from adjacent 4, 23, 42, and 60 yr-old 

pastures in the lower Fraser Valley of British 

Columbia was carried out. One hundred ramets of each 

species were collected from each pasture and planted 

in common garden conditions. The 1200 clones were 

assessed for a wide range of vegetative (e .g . stolon 

length, leaf length, plant height) and floral (e. g. 

flower number, peduncle length) characters. The

degree of variability within each population was, 

large and for most characters the mean values, and 

the variance, decreased with increasing pasture age. 

It is argued that the overall high diversity has 

resulted from the heterogeneity of the biotic 

environment, and the general decrease in diversity is 

attributable to continuous elimination of the less 

fit genotypes by competition and grazing. 

ACKERMAN, JAMES D.* ana ARLEE M. MONTALVO. 

Department of Biology, University of Puerto RicQ, 

Rio Piedras, PR 00931. -- Limitations to natural 

fruit production in Epiaend-rum ciliare, a tropical 

orchid. 

Natural fruit set of Epidendxrum ciliare (Orchidaceae) 

at one large population in Puerto Rico was 6 % 

during the first of two flowering seasons studied. 

The flowers are allogamous ana self-compatible. 

They lack pollen anda nectar rewards. In the second 

season, handa-pollinated 

more fruits (74k % fruit 

plaxits produced substaxntially 

set) than control groups 

(13 %), which suggests that the paucity of pollinations 

is one factor limiting natural fruit production 

at this population. However, other constraints are 

likely operating as well. Correlation anaalysis shows 

that large inflorescences have a higher percent fruit 

set than small inflorescences, yet most inflorescences 

are small. Thus, factors affecting the vigor 

of a planat may also contribute to the low fruit 

production of this species. 

ADAMS, JILL D. Department of Botany, University 

of Washington, and MILTON SMITH. College of 

Forest Resources, University of Washington, 

Seattle, WA 98195. 

- Using LANDSAT images to study plant 

A case in Hawaii. 

succession: 

LANDSAT images have been used for rapidly defining 

and classifying successional sequences on the lava 

flows of Mauna Loa, Hawaii. Mauna Loa, a shield-type 

volcano (elevation 

recorded ages that 

13,680 

extend 

feet), has flows of various 

from high elevations to sea 

level on both the wet and dry sides of the Island of 

Hawaii. 

primarily 

Successional patterns on the flows 

on the roughness of the substrate, 

depend 

the 

rainfall, and the elevation. The rougher aa flows 

have slower vegetation development than the smoother 

pahoehoe flows in all except the wettest regions. In 

addition, succession 

fern sparse forest, 

on aa often leads to an Ohia/ 

whereas pahoehoe flows of the 

same age and aspect will give rise to savannah and 

mixed Koa forest. On a given flow succession proceeds 

more slowly at higher elevations, thus it is 

often possible to observe a range of successional 

stages by examining the changes occuring in the 

LANDSAT spectral 

of the flow. 

signature from the top to the base 

ANTLFINGER, ANN E. Biology Department, 

University of Nebraska at Omaha, Omaha, NE 68182. 

- The genetic and ecological consequences of 

outcrossing in Impatiens capensis. 

Because genetic transmission occurs through the 

process of mating, a plant's mating system has signi- 

ficant effects on the genotypic structure and the 

dynamics of evolutionary change of plant populations. 

The mixed mating system of Impatiens capensis takes 

the form of floral dimorphism where chasmogamous and 

cleistogamous flowers are produced on the s-ame indi- 

vidual. To estimate the fitness of cleistogamous 


(CL) and chasmogamous (CH) individuals, germination, 

growth and survival of seedlings in field and green- 

house populations were compared. Mean percent field 

germination for spring, 1982, was 63.4 for CL seeds 

and 39.8 for CH seeds. CH seedlings were larger in 

size than CL seedlings. However, under uniform 

greenhouse conditions, growth rates were similar in 

both mating types. These experiments were repeated 

with seeds germinated in spring, 1983. Genetic 

variation was assessed using starch gel electrophore- 

sis and family-structured common garden experiments. 

ARMBRUSTER, W. SCOTT. Department of Biology, 

University of Alaska, Fairbanks, AK 99701. 

- Phenological Organization and Pollination 

Ecology of the Plant Communities on South-facing 

bluffs in the Subarctic. 

Flowering phenology and plant-pollinator relationships 

were observed on a series of south-facing bluffs in 

interior Alaska. The communities comprise a distinctive 

assemblage of plant and insect sp-ecies; many of the 

species are endemics, disjuncts, or vicariants of taxa 

of temperate North America or Asia. The major 

pollinators of the zoophilous flora include solitary 

bees (Andrenidae, Halictidae, Megachildae, Anthophoridae), 

Bombus (Apidae), and bee flies 

(Bombyliidae). Three functional flower classes were 

distinguished: open flowers, short-tube flowers, and 

long-tube flowers. Each class has a characteristic 

assemblage of pollinators. Overlap of flowering period 

among members of the same flower class was measured and 

compared with the overlap among members of different 

flower classes. Members of the open and short-tube 

flower classes had significantly less overlap than the 

null expectation, whereas long-tube flowers had more 

overlap. This difference may be a consequence of the 

fact that members of the open and short-tube classes 

share locations of pollen placement on pollinators with 

members of their own class, whereas long-tube species 

place pollen in 2-3 distinct locations on the 

pollinators' bodies. 

BASKIN, CAROL C.* and JERRY M. BASKIN. School 

of Biological Sciences, University of Kentucky, 

Lexington, KY 40506. - Germination ecophysi- 

ology of eastern deciduous forest herbs: 

Stylophorum diphyllum. 

Stylophorum diphyllum is an herbaceous perennial 

of mesic deciduous forests in the eastern USAo 

Seeds are dorrnant at dispersal in spring, and 

dormancy is due to a rudimentary embryo which 

requires incubation at low moist temperatures 

f or growth. In nature embryo elongation occurs 

during the cold season, and seeds germinate in 

early spring. A warm pretreatment is not re- 

quired for subsequent embryo growth and germ- 

ination. Embryos in freshly-matured seeds 

averaged 0.41 mm long, but after 10 w of 

chilling at 5 C they averaged 1.41 mm. Germ- 

ination of seeds incubated continuously at 5 C 

began after 11 w; after 19 w 80?% had germinated. 

Seeds chilled for 6 w germinated to 75 and 65?h 

at daily thermoperiods of 15/6 and 20/10 C, 

respectively, while 12 w of chilling were re- 

quired for comparable germination at 25/15 C. 

Seeds of S. diphyllum fit Nikolaeva's (1977) 

definition omrpophysiologica). complex 

dormancy .


BASKIN, JERRY M,* and CAROL C. BASKIN. School 

of Biological Sciences, University of Kentucky, 

Lexington, KY 40506. - Effect of temerature 

rrm == = 

dormant seeds of Lamium amplexicaule and 

ecological implications. 

Dormant spring-produced seeds of Lamium amplexi- 

caule afterripened when buried and stored over 

a range of temperatures, becoming conditionally 

dormant at low (5, 15/6 and 20/10 C) and non- 

dormant at high (25/15, 30/15 and 35/20 C) 

temperatures. Conditionally dormant seeds germ- 

inated to high percentages at 5 and 15/6 C, and 

nondormant seeds germinated to high percentages 

at 5, 15/6, 20/10, 25/15 and 30/15 C. Buried 

seeds that became nondormant in a greenhouse 

during summer were still nondormant after 12 w 

of storage at 30/15 C, while those stored at 

5 C for 12 w were conditionally dormant. Thus, 

low temperatures reverse the afterripening that 

occurs at high temperatures, but not that which 

occurs both at low and at high temperatures. 

Low winter temperatures cause dormant autumn- 

produced seeds and nondormant seeds in the soil 

seed pool to become conditionally dormant. 

BELL*, TIMOTHY J., AND JAMES A. OUINN. Department 

of Biological Sciences, Rutqers University, New 

Brunswick, New Jersey, 08903.-Effects of soil 

moisture on reproductive effort and its components 

in the perennial grass Dichanthelium clandestinum 

(L.) Gould. 

Individuals from six New Jersey populations of 

Dichanthelium clandestinum were grown in the qreen- 

house on a soil moisture gradient. Initial data show 

that total plant biomass was greatest at intermediate 

soil moistures sugoestino that high and low soil 

moisture ranges were stressful to the plants. Repro- 

ductive effort, ranging from 0.5% to 9.5%, was great- 

est at intermediate soil moistures. Percent alloca- 

tion to chasmogamty was consistently lower 

(KX=0.9?0.41SE) than allocation to cleistogamy 

(3.5?0.51) and showed a siqnificant positive correla- 

tion with total biomass. There was a small, but 

significant, neaative correlation between cleistoqa- 

mous allocation and total biomass. Under conditions 

of increasing soil moisture stress in D. 

clandestinum, total reproductive effort decreases, 

and the allocation to cleistoqarny increases at the 

expense of chasmogarny. This response appears to be 

related to the lower costs of cleistogamous seeds. 

*BERGERON, Y. and A. BOUCHARD. Centre de recher- 

ches ecologiques de Montreal et Departement de 

Sciences biologiques, Universite de Montreal, 

C.P. 6128, Succ. Aq,Montreal, Quebec, H3C 3J7. 

- Use of ecological groups in analysis and classi- 

fication of plant communities in a section of 

western Quebec. 

Plant communities analysis and classification were 

done for an integrated ecological study, in the lake 

Abitibi region, Quebec. Two levels of vegetation 

analysis were used: the ecological group level and 

the community level. Species were first grouped 

according to their sociological affinities. The 

ecol ogi cal si gni fi cance of those groupi ngs was stu- 

died by principal component analysis, with the inclu- 

sion of abiotic variables, and by the study of eco- 

logical profiles. Secondly, the concurrent use of 

ecological groups permitted the definition and caracterisation 

of noda. The relationships between the 

noda, in the space defined by the ecological groups, 

were analysed by principal coordinate analysis on 

which is superimposed the shortest spanning tree. 

Those combined analyses permitted the determination 

of 35 community types which vary mainly according 

to the surficial deposits (organic or mineral), the 

drainage, the relative richness of soils in bases, 

the submersion, the presence of bedrock outcrops, 

the fire perturbations and the microclimate. 

BERN, CHRISTINE M. Department of Biological 

Sciences, San Francisco State Universsity, 

San Francisco, CA 94132. 

- Factors influencing the distribution of 

Calamagrostis ophiditis, a serpentine endemic. 

Calamagrostis ophiditis is a serpentine endemic 

bunchgrass restricted distributionally to northern 

California. It is found generally in chaparral or in 

open grassy areas in shallow soils, and occurs rarely 

in deeper serpentine derived soils. This study is 

concerned with relative roles of biotic and physical 

factors influencing this pattern of distribution. 

Possible interspecific interference was examined 

using replacement series design experiments. 

Calamagrostis ophiditis was paired against two 

dominants from adjacent, deeper-soil serpentine areas, 

Stipa pulchra and Festuca idahoensis. Pairs were 

grown under greenhouse conditions reciprocally in 

three field-collected soils with six nutrient treat- 

ments. These results are compared to a preliminary 

field experiment of reciprocal transplants in a 

similar replacement series design. Initial data 

show C. ophiditis distribution is not correlated to 

the soil's calcium/magnesium ratio, but to areas of 

moderate to moderately-high levels of magnesium. 

BERRY, PAUL E. Dpto. de Biologia de 

Organismos, Univ. Simon Bolivar, Apartado 

80659, Caracas 1080, Venezuela. 

- Reproductive biology of five high eleva- 

tion species of Espeletia (Compositae) 

from the Venezuelan Andes. 

The breeding systems, phenology and pollina- 

tion systems of five high altitude species 

of Espeletia (sensu lato) were investigated 

in a Venezuelan paramo. All species are mon- 

oecious and are adapted for obligate out- 

crossing through the possession of genetic 

self-incompatibility. Natural seed set 

varies from 35% in high elevation popula- 

tions of E. mortiziana to 90% in the wide- 

spread E. schultzii. Each species has a dis- 

tinct flowering peak but flowers over a 2-3 

month period with sufficient overlap to 

allow simultaneous flowering of 4 species. 

Time from anthesis to seed dispersal is 

correlated with average plant size and alti- 

tude, lasting from 2 to 5 months in differ- 

ent species. No pollinators were observed on 

E. moritziana or E. timotensis, and the pos- 

sibility of wind pollination is being inves- 

tigated. Espeletia schultzii, E. batata and 

E. floccosa are widely pollinated by hum- 

mingbirds (Oxypogon), bumblebees and other 

bees or D;ptera, depending on weather con- 

ditions and density of flowering individuals.

BILDERBACK, DAVID E., CLINTON E. CARLSON, J. HENRY 

SLONE and STEPHEN C. MARVEL. Department of Botany, 

University of Montana and Forestry Sciences Laboratory, 

U.S. Forest Service, Missoula, MT 59812. 

- The effects of ash from Mount St. Helens on 

chlorophyll content, photosynthesis and radial stem 

growth of Douglas. fir (Pseudotsuga menziesii). 

During the eruption of Mount St. Helens on May 18, 

1980, a forest site south of Coeur d'Alene, Idaho received 

1.0 cm or more of ash. Needles of Douglas fir 

at this site retained 422 mg of ash/gm needle dry 

weight during the summer and fall of 1980. Trees 

northeast of Coeur d'Alene received a light dusting 

of ash. Chlorophyll content and radial growth of 

trees were compared at the two sites. Chlorophyll 

content of 1979 and 1980 needles heavily coated with 

ash was significantly less than the chlorophyll from 

needles lightly dusted with ash. There was no significant 

difference in the chlorophyll content of 1981 

needles or the radial stem growth. Seedlings of 

Douglas fir were artificially dusted with ash. Eight 

weeks later, needles had significantly less nonstructural 

carbohydrates than did needles of undusted 

plants. Ash-coated and control seedlings had similar 

dark respiration rates, compensation points and light 

saturation levels; however, ash-coated seedlings exhibited 

an enhanced photosynthetic rate. 

BRADFIELD, GARY E. and DANIEL GAGNON. Department 

of Botany, U.B.C., Vancouver, BC V6T1W5; 

Departement des Sciences biologiques, Universite 

du Quebec a Montreal, Montreal, PQ H3C3P8. 

- Correlations among strata and environmental 

gradients in forests of Vancouver Island, B.C. 

West central Vancouver Island vegetation data were 

used to investigate if forest strata patterns (trees, 

saplings, seedlings, shrubs, herbs and bryophytes) 

are correlated and if these strata respond similarly 

to environmental gradients. These hypotheses were 

evaluated with three data sets: (1) a moist coastal 

sector of the study area, (2) a dryer inland sector, 

and (3) a combined data set to provide greater envi- 

ronmental diversity. Product moment correlations 

and cononical correlation analyses were used to 

assess the degree of correlation among strata, and 

with environmental gradients. Patterns of correla- 

tion were different in each sector, with different 

strata showing the strongest correlation among them, 

as well as with environmental gradients. 

BRUEDERLE, LEO P.* and FOREST STEARNS. Biological 

Sciences (Botany), Rutgers University, New Bruns- 

wick, NJ 08854 and Department of Botany, University 

of Wisconsin, Milwaukee, WI 53211. - Ice storm 

damage to a southern Wisconsin mesic forest. 

In March 1976, an ice storm followed by strong winds 

struck southern Wisconsin. This storm deposited up 

to 12 cm of glaze causing substantial damage to wood- 

ed areas. At the UWM Cedar-Sauk Field Station a 

forest fuel sampling technique was modified to meas- 

ure macro-litter volume by species resulting from 

the storm. Changes in the canopy were photoassayed 

using wide-angle3and fish-eye lenses. The storm re- 

sulted in 19.1 m /ha macro-litter with approximately 

43 percent of the canopy removed. Damage was uneven, 

influenced by geographic and climatic factors. Wind 

and aspect of slope were found to be of particular 


ieportance with macro-litter volume virying from 22.6 

m /ha on the windward slope to 10.4 m /ha on the lee- 

ward. Ulmus rubra and Fraxinus americana suffered the 

heaviest damage and Ostrya virginiana and Tilia amer- 

icana the least. Biotic factors responsible for 

species susceptibility include growth form, wood me- 

chanical properties, age, decay, and phytosociological 

position. 

CARTER, M. El-OISE BROWN* AND WILLIAM H. MURDY. 

Biology Department, Agnes Scott College, 

Decatur, GA 30030 and Biology Department, 

Emory University, Atlanta, GA 30322. 

- Cha racte r D i sp l acemen t i n Ta l i n um menges i i 

(Po rtulacaceae). 

Character displacement was investigated in popula- 

tions of Talinum mengesii and T. teretifolium, 

which were sampled from granite outcrops along a 

100 mile transect, including both sympatric and 

allopatric populations. The results from analysis 

of floral traits, diurnal flowering times, herita- 

bility estimates, and experiments in the field, 

greenhouse and laboratory supported the hypothesis 

of unilateral reproductive character displacement 

in T. mengesii. The sympatric populations 

exhibited large flowers with long, exserted styles 

and early flower opening; characteristics which 

were shown to be important in reducing interspecific 

hybridization. Heritability estimates for the 

displaced traits were greater than 75%. Exserted 

styles in the sympatric populations resulted in 

a primarily outcrossing breeding system requiring 

insect-assisted pollination. Reproductive losses 

in these plants during periods of low pollinator 

activity may be compensated by a large number 

of ovules and extensive vegetative reproduction. 

CAZA,* CAROLINE L. and PAMELA t1. STOKES. 

Department of Botany, Universit y of Toronto, 

Toronto, Ontario, M5S lAl. 

-Variation in the distribution of Populus 

tremuloides on an unamended uranium tailings site, 

Ontario, Canada. 

Spatial variation in the biotic and abiotic environ- 

ment was studied in an aspen population on an un- 

amended uranium tailings site near Bancroft, Ontario. 

The site was divided into four zones based on type of 

ground cover. Vegetation and substrate character- 

istics were measured within each zone. Principal 

components analysis was used to summarize physical, 

chemical and biological differences between zones. 

The distribution of aspens on the site was correlated 

with substrate characteristics such as elevation, 

temperature, moisture and nutrient content. Other 

parameters displayed large variation within the site 

but were not related to aspen distribution. Addition- 

al data were collected from aspen populations on 

non-tailings (reference) sites. There was no indi- 

cation of differences in factors influencing dis- 

tribution between uranium tailings and these sub- 

strates. All physical and chemical factors measured 

on the tailings were within ranges reoorted for 

natural substrates. It is suggested that large vari- 

ation in these factors, occurring over small dis- 

tances on the tailings, is the most important deter- 

minant of aspen distribution on these wastes.


CID-BENEVENTO, CARMEN R.*, and PATRICIA A. WERNER. 

Kellogg Biological Station, Michigan State Univ., 

Hickory Corners, MI 49060. - Experiment on the 

relative effects of light and soil moisture on 

germination, survivorship and reproduction of 

old-field and woodland annuals. 

Seeds of two old-field (Chenopodium album, Polygonum 

pensylvanicum) and three woodland annuals (Acalypha 

rhomboidea, Pilea pumila, Impatiens capensis) were 

sown in a greenhouse in all combinations of six light 

levels (from 2%-100% of incoming sunlight) and three 

soil moisture levels (different sand:soil ratios). 

Germination, survivorship, plant size and total 

reproduction were monitored. Woodland annuals had 

higher germination and survivorship than old-field 

annuals for all treatment combinations, except those 

with 100% light. Light had no effect on germination 

of old-field annuals but high light significantly 

decreased germination of woodland annuals. Soil type 

had no effect on germination. Survivorship, seed 

production and size were greatest at intermediate 

light levels for both groups but the breadth of the 

peak varied between groups. Differences among light 

treatments in the seed production:emergent seedling 

ratio for both groups and differences between groups 

in seed dormancy seem most important in explaining 

their distribution. 

Clay, Keith. Department of Botany, Univer- 

sity of Texas, Austin, TX 78712. 

- Symbiotic mutualism between grasses and 

fungi. 

Survival, growth, and reproduction of ramets 

of the grass Danthonia spicata (L.) Beauv. 

infected by the systemic ascomycete fungus 

Atkinsonella hypoxylon Diehl were compared 

with noninfected ramets in one natural pop- 

ulation. D. spicata bears dimorphic chas- 

mogamous and cleistogamous flowers normally 

but infected individuals bear only cleist- 

ogamous flowers. Grasses not bearing simi- 

lar cleistogamous flowers are rendered 

sterile by infection by related fungi. The 

survival and growth rates and long-term 

reproductive rates of infected ramets were 

higher compared to noninfected ramets. The 

relationship between D. spicata and A. 

hypoxylon is therefore mutualistic rather 

than parasitic as has been reported in the 

literature. Other grasses (Cenchrus and 

Agrostis) are sterilized by infection but 

show increased vegetative vigor suggesting 

beneficial interactions between grasses 

and fungi are more widespread than pre- 

viously realized. 

CODY, MARTIN L. Department of Biology, 

University of California, Los Angeles, CA 90024 

-Multiple influences on cactus branching patterns. 

The branching patterns of columnar cacti were investigated 

in the Sonoran Desert (Baja California, 

Sonora and Arizona) and in adjacent thorn scrub and 

Mediterranean-climate coastal scrub. Within communities 

at a site species segregate by branching pattern, 

with species of larger stem radius taller and less 

branched. Photosynthetic area per unit volume scales 

as the inverse of stem radius, but capacity for rapid 

water uptake is proportional to stem radius and rib 

number. At higher latitudes both low temperature and 

low light may affect branching, and stem radius, but 

at lower latitudes water availability is a pre- 

dominant influence. Root systems apparently overlap 

between species within sites, but species with large 

stem radius appear to be shallow rooted and those of 

small stem radius deeper rooted. Climatic factors, 

local environmental factors, and biotic factors all 

influence branching pattern, with a major role played 

by the presence of other species. 

Colosi, Joe C., and P. B. Cavers, Biology Dept. 

Allentown College of St. Francis de Sales, Center 

Valley, PA 18034 and Dept. of Plant Sciences, 

University of Western Ontario, London, Canada 

N6A 5B7 

- Biotype by environment effects on winter seed 

survival. 

At least six biotypes of proso millet (Panicum 

miliaceum) are weeds of corn in southern Ontario. 

A black grained biotype is spreading faster than the 

others. We tested the idea that this difference is 

due to greater dormancy and winter survival of the 

black grains. In November 1981, grains of the six 

biotypes were sown at three soil depths: surface, 

5cm and 20cm. They were retrieved in April and June 

1982. Ungerminated grains were germinated in an 

incubater or tested for viablity with tetrazolium. 

Over 50% of the black grains were viable but dormant 

in June while most grains of the other biotypes were 

germinated or dead. Grains at the 5cm depth had the 

lowest dormancy and also the lowest survival of the 

three depths. We conclude that the higher grain 

dormancy and winter survivability of the black 

grained biotype contribute to its faster expansion. 

FLINN, MARGUERITE A.*, SHARON E. FISHER, 

EARL V. MARTIN. Mount Saint Vincent 

University, Halifax, N.S. B3M 2J6. 

- Seasonal nonstructural carbohydrate 

composition of rhizomes of forest 

understory species. 

Rhizomes of eight forest understory species 

were analyzed seasonally (spring, summer 

and autumn) for percent total nonstructural 

carbohydrate (% TNC) by determining the 

individual components: starch, fructosans, 

free reducing sugars and sucrose. Species 

studied were: Maianthemum canadense, 

Pteridium aguilinum, Cornus canadensis, 

Rhododendron canadense, Kalmia angusti- 

folia, Vaccinium angustifolium, Gaultheria 

procumbens and Chamaedaphne calyculata. 

The technique used was a modification of 

the Soxhlet alcohol extraction (Heinze and 

Murneek 1940) and enzyme hydrolysis with 

takadiastase (Smith 1969). Results gen- 

erally showed more % TNC in autumn than in 

spring and summer. Data indicated that the 

highest single nonstructural carbohydrate 

was the percent starch found in all species 

except for that found in M. canadense. 

In this species the percent fructosans 

was highest (51%). The amount of free 

reducing sugars was less than 4% in all 

species and sucrose was found in the least 

percent (1.5%). Ecological implication 

and recovery after fire will be discussed.

GAGNON, DANIEL and GARY E. BRADFIELD. Departement 

des Sciences biologiques, Universite du Quebec a 

Montreal, Montreal, PQ H3C 3P8; Department of 

Botany, U.B.C., 

- The vegetation 

Vancouver, BC V6T 1W5. 

of west central Vancouver Island, 

B.C.: a gradient analysis. 

Forests of the study area are dominated by Thuja pli- 

cata near the coast, and increasingly by Pseudotsuga 

menziesii progressing inland. The vegetation and 

soils were sampled in 172 plots to determine which 

environmental gradients could explain the observed 

patterns. Following successive reciprocal averaging 

ordinations, six distinct vegetation groups and 24 

community types were defined. An ordination (RA) of 

only the modal communities suggests that the predomi- 

nant vegetation pattern is under control of a "com- 

plex" precipitation - continentality climatic gra- 

dient. Variables strongly correlated with the ordi- 

nation's major axis were: positively, distance from 

the coast and fire disturbance, and negatively, wind 

disturbance and thickness of organic horizons/rooting 

depth ratio. Vascular species richness also increa- 

sed with distance from the coast. 

GALEN, CANDACE. Department of Botany, University 

of Texas, Austin, TX 78712 

- Ants, bumblebees, and seed production in floral 

scent morphs of Polemonium viscosum. 

Plants of Polemonium viscosum have flowers which are 

either sweet or skunky-scented. The effects of 

bumblebee pollinators and ant nectar thieves on seed- 

set in these morphs were examined at 3528 m and 3640 

m in alpine Colorado. The following patterns were 

found. 

Bumblebees accounted for 90% of the total pollin- 

ation at 3640 m, but only 50% of that at 3528 m. No 

differences in average seed-set of sweet and skunky 

morphs resulted from bumblebee visitation at either 

altitude. 

Ants reduced seed-set of sweet flowers at both lo- 

cations by negating the pollination effectiveness of 

bumblebees. Damaqe to floral tissues by ants prevent- 

ed subsequent fertilization or survival of ovules. 

Ants did not alter seed-set of skunky flowers. 

Activities of bumblebees and ants are therefore 

likely to influence success of P. viscosum. While 

ants may have significant effects on frequencies of 

floral morphs at both altitudes studied, similar con- 

clusions cannot be drawn about bumblebees from this 

experiment. 

GOVIL, SUDHA R. AND HARENDRA N. PAMTEYB 

Department of Botany, Banaras Hindu 

University, Varanasi - 221005,India. 

- Studies on the crop-weed interaction. 

The interaction of Cyperus rotundus(weed) 

with wheat and maize crops was studied at 

three densities and five ages under field 

conditions. There was 37-40% reduction in 

the weed density as the nuPber of crop 

plants (27 to 81 planLas m in wheat and 

4.5 to 13.5 plants m in maize)increased 

in the experimental plots. In wheat - 

Cyperus interaction, peak values of dry 

weight, leaf area, chlorophyll and N,P, K 

contents of the crop and weed plants 

showed 45-74% and 6-17% reduction respec- 

tively. Similarly in the maize-Cyperus 

interaction, the crop suffered mre (1&T7- 

7 5%) than the weed( 8-43%) . During the 


cropping cycle, in both maize and wheat 

fields, weed parameter values were higher 

relative to corresponding measures for 

crops in the earlier phases for dry matter 

production, leaf area index and standing 

crop of chlorophyll. The trend, however, 

was reversed at the later ages due to 

suppression of weeds by the crop, and the 

onset of weed' s senile stage. It is 

concluded that this serious perennial weed 

is equally harmful to both rainy and win- 

ter season crops and increasing density 

of crop plants proves to be more harmful 

for themselves thar to the weed. 

-Department of Botany, U.P.College, 

Varanasi-221002, India. 

GROVE, KATHRYN F. Department of Botany, 

University of Iowa, Iowa City, IA 52242. 

- A cryptic stylar outcrossing mechanism in an 

autogamous tropical herb: 

The stigma of Spigelia humboltiana Cham. & Schlecter 

(Loganiaceae) has a proximal region which is self- 

pollinated before anthesis and a distal region which 

may receive cross pollen. Thus, cross pollen appears 

to have a twofold disadvantage: it arrives on the 

stigma after self pollen and further from the ovary. 

Fluorescence microscopy was used to discoVer whether 

these apparent disadvantages to cross pollen are com- 

pensated for by differences in the timing of germina- 

tion or pollen tube growth of cross vs self pollen. 

Studies of open- and hand-pollinated flowers reveal 

that: 1)pollen does not germinate on the selfing 

region of the stigma until about 5 hours after 

anthesis; 2)pollen on the stigmatic tip, however, 

germinates promptly; 3)the earlier cross pollen 

arrives on the stigma, the greater are its chances of 

growth beyond the selfing region before self pollen 

germination; 4)some natural cross-pollinations are 

ineffective because pollen arrives too late; 5) 

there are no differences in self and cross pollen 

tube growth rates. Cryptic stylar outcrossing mech- 

anisms may occur in other autogamous species. 

HANYCH, DAVID A. Dept. Ecology & Behavioral 

Biology, University of Minnesota, Mpls., MN 55455. 

- The relation of seed size and seed weight to 

seed set in the white campion, Lychnis alba 

(Caryophyllaceae). 

Mature Lychnis alba capsules were randomly and 

selectively collected from an old field population 

during two sampling years (1981 & 1982). The mature 

seeds from each capsule were dried to constant weight 

and then sized by measuring the axis parallel to the 

hilum using a dissecting microscope equipped with an 

ocular micrometer. A significant positive correla- 

tion was documented between mean seed size and mean 

seed weight on a per capsule basis during both 

sampling years. However, both mean seed size and 

mean seed weight were inversely related to the number 

of seeds per capsule during both years. Similar 

statistically significant trends were observed among 

capsules collected from individually marked plants 

during 1982. Since seed weight may be considered a 

measure of the energetic investment in a seed by the 

plant, the variance in relative investment per seed 

as a function of capsule seed number may reflect a 

reproductive effort characterized by variable 

resource allocation to seeds within individual fruits.


HAYNES, JARED* and MICHAEL R. MESLER. Department 

of Biological Sciences, Humboldt State University, 

Arcata, CA 95521. 

- Pollen foraging by bumblebees: foraging patterns 

and efficiency on Lupinus polyphyllus. 

Bumblebees foraging on vertical inflorescences start 

near the bottom and work up, behavior commonly 

interpreted as a response to greater amounts of 

nectar available in lower flowers. Lupinus polyphyllus, 

which produces no nectar, has more pollen 

available in upper flowers. Although bees ane 

probably unable to detect any gradient, since pollen 

is hidden in each flower's keel, they still start 

low and forage up. Therefore we concluded that the 

bees' tendency to forage upward on vertical inflorescences 

is not tied to a reward gradient. In addition, 

bees use only about 15% of the flowers per inflorescence, 

although they could be much more efficient by 

visiting and revisiting every flower systematically. 

In general, revisits would not be penalized because 

only a small portion of the pollen in a keel is 

dispensed at each visit. Such gross inefficiency may 

be explained as a transferal of efficient nectargathering 

behavior patterns to pollen inflorescences. 

HERNANDEZ, HELIOS. 16 Valleyview Drive, Winnipeg, 

Manitoba, Canada, R2Y OR6. 

- Effects of winter roads on terrain and vegeta- 

tion: Initial response and subsequent recovery. 

Three winter road test sites were examined in 1981: 

summer 1, ice-aggregate work pad, Quill Creek, Yukon; 

summer 9, ice-capped snow road and ice road, Norman 

Wells, N.W.T.; summer 8, snow road, Inuvik N.W.T. 

Initial responses at Quill Creek were similar to 

those at Norman Wells in 1973 (Arctic 30(1): 13-27 

(1977)) and at Inuvik in 1974 (Proceedings Third 

International Permafrost Conference (1978), Edmonton: 

481-486). Total live plant cover was greatly reduced 

and peat bulk density increased. Thaw depth response 

differences between sites are attributable to canopy 

density differences and subsequent site history. 

Recent winter use of the Norman Wells site retarded 

recovery. Recovery at Inuvik, however, continued. 

The shrub layer was well developed and ground cover 

extensive. When compared to adjacent, unprotected, 

similarly-disturbed areas, properly built and main- 

tained winter roads can protect underlying terrain 

and vegetation. 

HOGG, E.H. & J.K MORTON, Department of Biology, 

University of Waterloo, Ontario, Canada,N2L 3G1. 

The Effects of nesting gulls on the flora, 

vegetation and soils of islands in the Great 

Lakes. 

Nesting Ring-billed and Herring Gulls were observed 

to have a profound effect on the flora, vegetation 

and soil of Barrier Is. (a limestone island in 

Georgian Bay) during a 4-year study period. Annual 

aliens dominated the nesting site and native species 

were almost eliminated. Nutrient levels in the soil 

increased dramatically. The gulls commute from the 

island to the mainland to forage on garbage dumps and 

arable land. They are effective agents of dispersal 

for weed seeds which grow successfully in the 

disturbed nutrient-rich soil of nesting sites. 

Succession in the vegetation of abandoned nesting 

areas was characterized by a rapid decline in annual 

aliens as perennial native grasses become 

established. Nutrient levels in the soil rapidly 

returned to near normal except for phosphorus which 

persisted at high levels. After 4 years, species 

composition in the regenerating vegetation was still 

very different from that in undisturbed areas. 

HOPKINS, DALE R. AND V. THOMAS PARKER*. 

Department of Biological Sciences, San Francisco 

State University, San Francisco, CA 94132. 

- Seedling emergence and the seed bank of a salt 

marsh in northern San Francisco Bay. 

Abundance, species composition and distribution of 

buried seeds in a San Francisco Bay salt marsh were 

studied by collecting soil samples in October and 

February and observing seedling emergence in the 

greenhouse. Results were compared with existing 

vegetation patterns and field germination. Average 

numbers of2buried viable seed do n to a 5 cm depth 

were 380/m in October and 700/m 2in February, with 

field germination averaging 118/m . Salicornia 

virginica dominated the seed bank in th-e greenhouse 

and in the field germination. Most other marsh 

species were present in the seed bank but numbers of 

seeds were low. A significant correlation was found 

between highest species diversity and proximity to 

intramarsh channels. The nature of the seed bank 

reflects the dominance of perennial species, seed 

dispersal patterns, tidal influence and selective 

environmental pressures. 

HURT, VALINA KAY. Department of Botany- 

Microbiology, University of Oklahoma, 

Norman, OK 73019. -Allelochemic effects 

on the growth of Thiobacillus ferrooxidans 

Temple and Colmer, a bacterium involved In 

acid mine drai.nage. 

Acidic water drainage with a pH as low as 

2.2 is common for strip mine areas. This 

acid mine water is partielly due to the 

bacterium, Thiobacillus ferrooxidens Temple 

and Colmer which oxidizes iron pyrite. This 

bacterium is an obligate chemolitho- 

autotroph. Any chemical inhibition of this 

species might prove to be an important 

management tool in reclamation. This study 

showed inhibition of T. ferrooxidans growing 

in T. ferrooxidans media by sterile dilute 

extracts from leaf and litter leachates and 

root exudates of 100%, 80%, 60%, 40%, and 

20% concentrations. Distilled water was 

used as the control. A total of 47 orphan 

coal strip mines were surveyed. Sixty-three 

tree species of L3 different genera were 

examined. Extracts from the following 

species inhibited T. ferrooxidans growth: 

Acer saccherinum, A. negundo, Celtis 

laevigats, Juglans nigra, Platanus 

occidentalis, Quercus marilandica, Q. 

falcata, and Q. stellata. Abandonel coal 

strip mines having a combination of these 

species have lower populations of the 

bacterium. 

KEDDY, CATHY 

J. 644 Chapel St., Ottawa, Ontario, 

KlN 7Z9. 

- 60 years after Fernald- Sabatia kennedyana and 

Coreopsis rosea in southwestern Nova Scotia. 

About 60 years ago, M.L. Fernald discovered a dis- 

junct occurrence of Atlantic Coastal Plain species in

southwestern Nova Scotia. Two of the rarest of these 

species are Sabatia kennedyana and Coreopsis rosea 

found only in the Tusket area of Yarmouth Co. In the 

summer of 1982, this area was explored to obtain in- 

formation on abundance, distribution and threats to 

these species. Both were found on gently sloping, 

sheltered, gravel and peat lakeshores which are 

alternately flooded and exposed with fluctuating 

river levels. During low water years, these species 

flower (July to Sept.). As well, they reproduce by 

stolons or rhizomes. S. kennedyana occasionally 

forms dense colonies (two bays had more than 1000 

plants in flower). C. rosea was restricted to two 

lakes through which the Tusket R. flows plus one that 

drains directly into it. S. kennedyana occurred in 

six lakes forming part of a 30km stretch of the river 

and two lakes draining into it. When Fernald col- 

lected in 1920 and 1921, both species were also 

present in the lowest lakes in the Tusket and Carleton 

river systems, but have since been eliminated from 

the lower Tusket (and probably Carleton) lakes be- 

cause they have been turned into reservoirs for the 

Tusket Falls generating station. In the remaining 

lakes, the major threat to both species now is cot- 

tage development accompanied by vehicle traffic along 

the shoreline during low water periods. Some of the 

largest populations of S. kennedyana and the largest 

population of C. rosea occur on shorelines which are 

already heavily cottaged. 

KEELER, KATI-ILEEN H. School of Life Sciences 

University of Nebraska, Lincoln, NE 68588-0118 

- Plants with Extrafloral Nectaries in Ecosystems 

Without Ants 

Extrafloral nectaries are plant glands which secrete 

water, sugars, and amino acids present anywhere 

except in the flower. These secretions attract numerous 

nectar-feeding insects other than pollinators. 

They have been repeatedly shown to be the site of antplant 

mutualism: plants are protected from herbivores 

by ants while the ants receive food. Since 

there are no ants native to Hawaii, it was hypothesized 

that none of the endemic plants would have 

extrafloral nectaries. 

Thirty-one of 614 species growing in Hawaii Volcanoes 

National Park have extrafloral nectaries. Ten 

of these are of pantropic distribution or were introduced 

by the Polynesians, 19 are recently introduced 

exotics and 2 are endemics. Acacia koa, (Fabaceae) 

and Pteridium aquilinum var. decompositum (Polypodiaceae) 

are the endemics with functional extrafloral 

nectaries. Two species which produce extrafloral 

nectar elsewhere, Passiflora foetida and Ipomoea 

indica do not secrete nectar in H.V.N.P. The abundance 

of EFN-plants in H.V.N.P. communities is low: 

except for koa-dominated sites, cover by plants with 

extrafloral nectaries was less than 3%. It is impossible 

to evaluate the complete flora of the Hawaiian 

islands but plants with EFNs occur occassionally 

in additional endemic species, e.g. Ipomoea tuboides 

(convolvelaceae), and Hibiscus (Malvaceae), and an 

endemic genus, Kokia (Malvaceae). Despite this, 

frequency of plants with extrafloral nectaries is 

very low in Hawaii compared to other floras. It is 

hypothesized that plant species evolving in Hawaii 

tended to lose nectaries, but that a few species 

established mutualism with some, presently unknown 

Hawaiian invertebrate. 


LABOVITZ, MARK L., ROBIN BELL*, AND EDWARD J. 

MASUOKA. NASA/GSFC, Code 922, Greenbelt, MD 

20771. -Delay of winter dormancy recovery in 

Quercus spp. 

mineralization. 

associated with anomalous soil 

Vegetation growing in mineralized versus non-mineralized 

soil was examined in early Spring for the 

potential of using remote sensing techniques to 

discriminate the two environments. Two test sites, 

located in the Mineral Sulphide District, Louisa 

County, VA, differed only in that one was situated 

on a mineralized contact. At both sites, 16 trees 

(Quercus spp., predominantly Q. alba L.) arranged in 

a 4x4 matrix, were observed repeatedly during recovery 

from winter dormancy. As buds broke, the 

percentage of burst versus closed was tallied. 

During leaf flush, nominally 50 measurements per 

tree of the maximum blade lengths both parallel 

to and normal to the midvein were collected. 

Results show 1) the percentage of buds burst 

remained higher at the non-mineralized site for 

more than two weeks after observable recovery from 

dormancy had begun; and 2) non-mineralized leaves 

possessed a greater surface area for a period of at 

least two weeks. 

LACEY, ELIZABETH P. AND CINDY CAPPS Department 

of Biology, University of North Carolina, 

Greensboro, NC 27412 - Latitudinal variation in 

seed viability in Daucus carota. 

Daucus carota grows in old fields and along 

roadsides from Georgia into southern Canada. Seed 

tests both indoors under controlled conditions and 

outdoors in experimental plots show that southern 

populations set fewer viable seeds than do northern 

populations. Tests of seeds produced in reciprocal 

transplant plots in North Carolina and Michigan 

indicate that these differences are environmentally 

rather than genetically based. Developing seeds in 

southern populations appear to suffer more insect 

damage, suggesting that biotic factors may help 

regulate population size more in the southern part 

of the species' range. 

LECHOWICZ, MARTIN J. Department of Biology, 

McGill University, Montreal, Quebec, Canada 

H3A lBl - The defenses of deciduous trees against 

defoliation by the gypsy moth, Lymantria dispar 

From 1979 through 1981 I studied the leaf character- 

istics of 14 deciduous tree species in a southern 

Quebec forest in relation to their utilization by 

gypsy moth. Traits that might influence host selec- 

tion by gypsy moth were monitored: leaf phenology, 

toughness, water content, nitrogen concentration, 

tannin and phenolic concentrations, and leaf acidity 

and buffer capacity. Defoliation was higher on tree 

species that have more tender, nitrogen- and water- 

rich foliage during the period of larval dispersal 

in early spring. Since these qualities favorable 

for gypsy moth larvae diminish rapidly with leaf 

age, trees that leaf out relatively early escape 

serious defoliation. Defoliation levels among trees 

leafing out later are mediated at least in part by 

leaf chemistry. Defoliation is less on trees with 

young leaves that have relatively high concentra- 

tions of condensed tannins and greater on trees with 

acidic young leaves rich in phenolics and hydrolyz- 

able tannins but poor in condensed tannins.


LEE, PETER F. Department of Biology, Lakehead U., 

Thunder Bay, Ontario, P7B 5E1. STEWART** JOHN M. 

Department of Botany, U. of Manitoba, Winnipeg. 

Manitoba, R3T 2N2. 

- Selected environmental characteristics of 

commercial wild rice 

NE Minnesota. 

stands in NW Ontario and 

Before optimizing the commercial management of 

natural wild rice stands, the ecological relationship 

s of wild rice should be understood in terms of their 

biological, chemical and physical requirements.71 

commercial stands were sampled between late July and 

mid August during peak biomass. Observations and 

determinations were made on plant density, seeds per 

panicle, seed length, dry weights of plant organs and 

plant tissue, water and sediment analyses of Fe, Mn, 

Zn, Ca, Mg, K and P concentrations. Chemical 

characteristics indicate that wild rice grows in 

either soft or moderately hard waters and within 

aerobic to anaerobic moderately acid sediments. The 

elemental concentrations of wild rice leaves are 

similar to those found in other macrophytes, except 

for P, which was below normal. Plant tissue 

concentrations were poorly correlated with the 

corresponding elemental concentrations in sediments. 

Changes in water depth (0.42-1.20m) from year to year 

are thought to be responsible for the fluctuations 

in the size of commercial harvests. 

LIEFFERS VICTOR J. AND JOHN S. CAMPBELL. 

Department of Biological Sciences, University of 

Lethbridge, Lethbridge, Alberta Canada TlK 3M4 

-Productivity of PopuZus tremuZoides in even-aged 

stands in northeastern Alberta. 

The circumference at breast height was measured on 

all trees,in 20 X 20 m plots, in 39 even-aged PopuZus 

tremuZoides stands. Increment cores or cross-sectional 

discs were collected from 10-15 randomly selected 

trees. For each of these trees, the radial 

increment for five years preceding the current year 

was determined. In each stand, the increment in 

radius of each tree was proportional to the circumference 

of that tree. Using this relationship and 

the nlean circumference of all the trees in the plot, 

the mean change in basal area and biomass for the 

entire stand was determined by double sampling by 

regression. Stands ranged from 21 to 55 years old. 

The mean change in biomass per tree was greatest in 

the older stands and stands with low stem density. 

Aboveground net production varied from 1.1 to 4.7 

t/ha/yr, which is lower than values reported for the 

Great Lakes area. 

LINK, STEVEN O. * and THOMAS H. NASH III. 

Department of Botany and Microbiology, 

Arizona State University, Tempe, AZ.85287. 

- A mathematical model of lichen gas ex- 

change based on laboratory data for the 

prediction of field data. 

Laboratory data consisted of net CO2 gas ex- 

change at several levels of light and temp- 

erature while thalli dried from full satura- 

tion. Estimates of internal CO2 were de- 

rived from drying curves by considering re- 

sistance to be propor tional to water content 

Parameter estimates include a light use ef- 

f iciency of 0.022 mmole CO2 mE~l, an energy 

of activation for carboxylatiLon of 5 9000 J 

mole1l, an energy of denaturation of 108000 

J mole'1, an entropy of denaturation of 364 

J mole'1 C-1, an energy of activation for 

dark respiration of 36000 J mole , and the 

water content yielding a half-maximal dark 

respiration rate of 77%. The model had an 

R2 of 0.85. When the model was applied to 

field data 76% of the variation was ex- 

plained. Field rates were underestimated in 

some cases possibly due to handling, short 

term adaptation to laboratory conditions, or 

population variation. 

MARSH, LELAND C. and PAUL E. BORK*. Biology 

Department, State University of New York 

Oswego, NY 13126 

-Bioaccumulation of cadmium, lead, and zinc in 

Typha latifolia under experimental conditions. 

Dormant rhizomes from a single clone of T. latifolia 

were grown for 90 days in the qreenhouse and treated 

with increasing doses of three heavy metals. There 

were no observable external differences in the aerial 

portions of the treated vs. the control plants, 

even though the final doses were 10,000 ppm. The 

data include biomass yield, aboveground/belowground 

ratios, growth rates of aerial plants, and concentrations 

of heavy metals in all plant parts and at 

three soil levels. Typha latifolia accumulates significant 

quantities of heavy metals. Data are presented 

for the accumulation rates of cadmium, lead, 

and zinc in kg/hectare. 

MAUN, M. A. Department of Plant Sciences, 

University of Western Ontario, London, Ontario 

N6A 5B7. - Colonizing ability of Ammophila 

breviligulata through vegetative reproduction. 

The plant populations of A. breviligulata expanded 

towards the lake by forming an advancing front 

consisting entirely of plagiotropic rhizomes. Ice 

thrust up against the high beach, violent storm 

waves and water currents destroyed the lakeward 

end of the population, thus fragmenting rhizomes 

into varying lengths and creating bare areas below 

the farthest inland reach of waves. Fragmented 

rhizomes were dispersed by wave action and 

consequently served as important sources of new 

plants in alien habitats. The rhizome fragments 

occurring in greatest frequency contained 2 to 5 

nodes. Only a few of the rhizome buds developed 

into new shoots. Severing of the rhizome into 

single node units caused a significant increase in 

bud initiation. However, a large proportion (76%) 

of the initiated buds aborted and the shoots failed 

to emerge from the soil. 

MCBRIEN, HEATHER, RUDOLF HARMSEN and ADELE CROWDER, 

Department of Biology, Queen's University, King- 

ston, Ontario, K7L 3N6 

- Plant-herbivore interaction in Solidago cana- 

densis L. and Trirhabda spp. 

Solidago canadensis is often the dominant plant in 

abandoned hayfields. Plant cover and arthropod num- 

bers have been monitored since 1975 in sample plots 

in Leeds Co., Ontario. During a population build-up 

of Trirhabda, whose larvae eat goldenrod leaves, the 

cover of goldenrod declined. Cover of grasses in- 

creased. Adult beetles emigrated, and the local

population of larvae crashed as food diminished. 

Goldenrod cover did not return to pre-outbreak values 

but, when insecticide was used, goldenrod recovery 

was greater. Manual defoliation was used to mimic 

the damage by larvae and three defoliations during 

the summer reduced cover in the subsequent year. 

MCKERNAN*, J. MICHAEL & JENNIFER M. $HAY. 

MacLaren Plansearch Inc., Winnipeg MB R3G OT6 

Department of Botany, U. Manitoba, Winnipeg MB 

R3T 2N2. 

- Effects of military training on mixedgrass 

prairie and utility of recovery procedures. 

Stressed and control areas were studied within the 

C.F.B. Shilo Military Reserve, 40 000 ha of 

Bouteloua-Stipa-Carex mixedgrass prairie on light 

sandy soils 25 km east of Brandon, Manitoba. Since 

1974, military manoeuvers using tanks and armoured 

personnel carriers have been conducted annually. 

Impacts arising include increased frequency of 

Bouteloua gracilis (6-64%) and Carex spp (19-56%), 

reduced species diversity (26-30%), and increased 

litter (8%) and bare ground (240%). Penetrometer 

soil strengths were 50% greater in stressed areas. 

Most soil chemistry variables show increased con- 

centration (Cu 88-934%, Zn 16-111%, Na 3-101%) in 

response to a military stress gradient. 

Recovery procedures tested indicated that greater 

renovation was achieved by light harrowing of 

damaged areas and 2 years' protection than by 

seeding with combinations of Agropyron intermedium, 

A. cristatum, A. trachycaulum, Bromus inermis, 

Elymus junceus, Festuca rubra, Medicago sativa, and 

Melilotus officinalis and similar protection. 

McLEOD, KENNETH W., THOMAS G. CIRAVOLO, K. C. 

SHERROD, JR. Savannah River Ecology Laboratory, 

Aiken, SC 29801 - Fertilization of pine forests: 

canopy response. 

Loblolly pine forests on the Savannah River Plant 

have been fertilized at rates of 400 and 800 kg 

N/ha by the addition of sewage sludge. Two types 

of sludge representing aerobic and anaerobic 

digestion processes were used. The plots treated 

with anaerobically digested sewage sludge had 

increased elemental concentrations of nitrogen and 

phosphorus in the throughfall and greater amounts of 

needlefall. The response increases with an increase 

in the fertilization rate. High rates of needlefall 

during the late summer were also observed in this 

treatment. Aerobically digested sewage sludge, 

which contains a much higher percent of solids and 

which appears to not have decomposed substantially, 

has had no effect to date on either throughfall or 

needlefall. Whether the increased amounts of N and 

P moving from the canopy to the forest floor will 

continue to cycle and furnish trees with increased 

nutrients or be bound and immobilized by the forest 

floor is as yet unknown, but could strongly effect 

future productivity. 

MCMILLEN, JACK D.* and THEODORE J. CROVELLO. 

Department of Biology, 

Notre Dame, IN 46556. 

University of Notre Dame, 

- Quantitative determination of macroclimatic 

niches of Pinus species in the eastern U.S. 

We captured 

distribution 

data on 30 climatic 

of 14 Pinus species 

variables and the 

in 211 state cli- 


matic divisions of the eastern U.S. Discriminant 

analysis indicated how much of the distribution could 

be described by climatic variables and which of these 

variables are the best descriptors. Tree distribu- 

tions can also be represented in terms of statistical 

distributions of each climatic factor (i.e. means and 

standard deviations). Discriminant analysis using 

all variables estimates the distribution of each spe- 

cies at greater than 93% accuracy. In most cases, a 

few factors give 90% accuracy. Additional variables 

contribute little information due to correlation with 

other variables. Different climatic factors are 

important for different species. 

Meidinger, Del V. Research Branch, British 

Columbia Ministry of Forests, 1450 Government 

Street, Victoria, British Columbia, Canada, 

V8W 3E7 

Ecosystem classificatiorn in British Columbia 

and its application to forest management 

Since the early 1970's, the British Columbia Ministxy 

of Forests has been developing and implementing a 

system of ecological classification designed to pro- 

vide a rational framework for both forest and range 

management. The classification system follows, 

with some modification, the Biogeoclimatic Ecosystem 

Classification system developed by Dr. V.J. Krajina 

and his students. The units result from a synthesis 

of vegetation, soil, and climate data. The pro- 

vince is presently divided into thirteen biogeo- 

climatic zones and 122 biogeoclimatic subzones. The 

classification for one subzone of the Interior 

Cedar - Hemlock zone will be presented and compared 

with adjacent subzones. Ten biogeocoenotic associ- 

ations, which occur primarily along a moisture 

gradient, have been differentiated in the Wet 

Interior Cedar - Hemlock subzone. Utilizing the 

classification framework, silvicultural interpreta- 

tions for tree species selection and site prepara- 

tion have been developed. 

MURDY, WILLIAM H.* and DONALD L. PHILLIPS. 

Department of Biology, Emory University, Atlanta, 

GA 30322. 

- Effects of Rhododendron maximum L. on regenera- 

ion of southern Appalachian hardwoods 

Long-term forest inventory data at the Coweeta 

Hydrologic Laboratory, North Carolina, were used to 

assess the changes in tree regeneration patterns 

since 1934-35 and to evaluate the impact of 

Rhododendron maximum L. Density diameter 

distributions of dominant tree species were 

determined from 1934-1935 and 1969-1972 inventories 

of high density rhododendron (HR) and low density 

rhododendron (LR) plots. Oak and maple 

regeneration, which was abundant in 1934-35 due to 

past disturbance, decreased by 1969-72 as the 

canopy closed. Total tree regeneration was lower 

in HR plots than in LR plots and the magnitude of 

the difference increased with time. In 1969-1972, 

regeneration of chestnut oak and white oak was 

reduced in HR plots, whereas that of red maple was 

not. Scarlet oak and black oak regeneration was 

reduced at all sites regardless of rhododendron. 

Hemlock sapling density increased with time and 

abundance of rhododendron.


Nash III, Thomas H. and W. Bradley Kincaid. 


State University, Tempe, AZ 85287 

- Relationship 

chronological 

of SO2 and climate 

variation in western 

to dendrolarch. 

The effect of sulfur dioxide on growth of western 

larch (Larix occidentalis) near Trail, British Columbia, 

was examined using tree-ring analysis in a montane 

forest ecosystem of the Pacific Northwest. A 

previous investigation demonstrated association of 

long-term growth variation at several sites within 

the Columbia River valley with estimates of sulfur 

emissions. Herein, we report results of a regression 

study using a portion of the tree-ring chronologies 

for which 30 years of SO monitoring 

2 

able. To assess tree-ring variation 

data were 

in relation 

availto 

climate, data from two control locations were used to 

build a regression model in which the principal varables 

were 1) last year's tree-ring index, 2) spring 

temperature, 3) autumn precipitation, and 4) last 

year's summer temperature. For the Columbia valley 

sites, this model explained less than 30% of the variation. 

cantly 

Inclusion 

increased 

of seasonalized So2 data signifithe 

variation explained for these 

regressions 

predictions. 

and enable us to make dose-response 

Nicholson, A.C. and E.H. Hamilton. Research 

Branch Ministry of Forests, 1450 Government 

Street, Victoria, British Columbia, Canada, V8W 3E7. 

Grasslands of southern interior British Columbia 

Climax grasslands dominated by bunchgrass and semi- 

desert shrubs occur on Chernozemic soils in the major 

valleys of southern interior British Columbia. A 

Braun-Blanquet table sort and ordination techniques 

were used to delinate five major ecosystems. The 

Agropyron spicatum - Artemisia tridentata association 

occupies the hot dry valley bottoms (below approxi- 

mately 600 m) on Brown Chernozemic soils. The 

Agropyron spicatum - Poa sandbergii - (Chrysothamnus 

nauseosus) association occupies a less arid band 

at approximately 600 to 900 m elevation on Dark 

Brown Chernozemic soils. Bordering the forest at 

elevations ranging from approximately 800 to 1200 m 

are: the Agropyron spicatum - Festuca spp. associa- 

tion (south of 51 N lat.); the Agropyron spicatum - 

Koeleria macrantha - (Artemisia frigida) association 

(predominately north of 51 N lat.); and the Stipa 

richardsonii association (extensive on moist sites 

north of 51 N lat.). These latter associations 

are characterized by Dark Gray and Black Chernozemic 

soils, a cooler moister climate and a more diverse 

and productive vegetation. 

PAEZ, ALEJANDRA*, HENRY HELLMERS AND BOYD R. STRAIN 

Botany Department, Duke University, Durham, NC. 

27706. - CO9 enrichment and drought stress interaction 

in determinate and indeterminate cultivars. 

The interaction of increased atmospheric carbon 

dioxide and drought stress was investigated in determinate 

and indeterminate cultivars 

sativum) and tomato (Lycopersicum 

of pea (Pisum 

esculentum). 

Plants were grown in controlled environments using 

low and high GO2; well-watered and drought-stressed 

regimes. When water was withheld total leaf water 

potential and osmotic potential decreased less 

rapidly under the high CO2 regime. Thus, high CO2 

plants maintained positive turgor 'and did not wilt 

when drought-stressed. The differences were due to 

the reduced stomatal conductance and reduced trans- 

piration. Additional CO2 had no effect on branch 

number. Drought stress inhibited branch development 

in pea and significantly reduced it in tomato. 

Elevated CO2 partly overcomes the inhibiting effect 

of drought stress on plant growth and results in a 

more rapid recovery of drought-stressed plants. 

These results have important ecological significance 

because the relative competetiveness of plant species 

in ecosystems may be altered. 

PARRISH, JAY B.* Department of Geophysics, Penn 

State University, University Park, PA 16802 

ROCK, Barrett Jet Propulsion Laboratory, 

Padadena, CA 91109. 

-The effect of soil methane on in vitro growth 

and vigor of Quercus prinus seedlings. 

A suspected site of hydrocarbon microseepage in Lost 

River, West Virginia, is marked by high soil Mn 

content and an anomolous growth of Acer rubrum to 

the exclusion of the dominent species in the region, 

Querus prinus. An in vitro experiment tested the 

hypothesis that hydrocarbon microseepage adversely 

affects the ability of Q. prinus to absorb necessary 

nutrients by interfering with its ectomycorrhizal 

fungal association. Plants grown in soil collected 

from the gas field had a very high Mn content. 

Plants exposed to methane had lower amounts of 

essential elements than those exposed to air; this 

is consistent with the hypothesis that 

ectomycorrhizae are adversely affected by methane. 

PIIILBRICK, C. THOMAS. Dept. of Botany and Plant 

Pathology, University of New Hampshire, Durham,NH. 

03824. - Aspects of pollination and floral biology 

in three Potamogeton species. 

Field experiments were conducted on P. spirillus, P. 

epihydrus and P. pusillus; all three are protogynous. 

Stigma receptivity lasts beyond anther dehiscence in 

P. epihydrus and the aerial flowers of P. spirillus, 

and the pollen is self-compatible. Self-pollination 

occurs after anther dehiscence if outcrossing has not 

taken place; facultative autogamy. Potamogeton 

spirillus produces dimorphic flowers, facultatively 

autogamous aerial flowers, borne on many-flowered 

inflorescences which are larger than the obligately 

autogamous submersed flowers, borne on few-flowered 

inflorescences. Autogamy is illustrated by consistent 

100% fruit production on bagged inflorescences. In 

P. pusillus, anthesis occurs on both aerial and sub- 

mersed flowers, but the flowers are not dimorphi as 

in P. spirillus. Submersed anther dehiscence is char- 

acterized by production of gas bubbles expelled from 

the anther sac. Pollen is released from the anther 

sac on the bubble surface. Apparent self-incompati- 

bility of the pollen suggests that bubble production 

aids in outcrossing. The obligate outcrossing nature 

is illustrated by no fruit production on bagged 

inflorescences. 

PITELKA, LOUIS F. and JEFFREY W. ASHMUN*, Biology 

Department, Bates College, Lewiston, Maine 04240 - 

Survival, growth and reproduction of Aster 

acuminatus in reciprocal transplant gardens. 

A reciprocal transplant experiment was undertaken to 

determine the extent to which variation in growth and 

reproduction among patches of Aster acuminatus is 

genetic versus environmentally-induced. In April,

1980, 200 ramets of A. acuminatus were collected from 

each of two different source populations and divided 

equally among eight transplant gardens. Transplanted 

ramets were censused at regular intervals through the 

summer of 1982 and then harvested. Data were 

collected on survival, growth, reproduction and 

resource allocation. Significant variation among the 

gardens in several important demographic variables 

was correlated with microenvironmental differences. 

By 1982, the number of ramets in the gardens ranged 

from 48 to 148 and the percent of ramets that 

flowered ranged from 0% to 22%. There were few 

source population effects suggesting that environment 

is more important than genotype in determining growth 

and reproduction in this understory herb. 

PITELKA, LOUIS F.*, SANDRA B. HANSEN and JEFFREY 

W. ASHMUN, Biology Department, Bates 

Lewiston, Maine 04240 - Growth rates 

College, 

and 

longevities of patches of Clintonia borealis. 

Patches of Clintonia borealis can be found in a wide 

range of understory microenvironments and can vary 

dramatically in total ramet number, density and mean 

ramet size. Pooled demographic data from 16 patches 

show that overall rates of ramet mortality and 

branching (vegetative reproduction) are low. 

Recruitment from seeds is extremely rare. Although 

irLdividual patches show some variation in net rates 

of clonal growth, the pattern of slow to moderate 

growth over a period of years is remarkably 

consistent among patches. Additional data on patch 

growth rates comes from excavating small patches and 

counting internodes and branch points. These data 

confirm the patterns revealed by the demographic 

data and show that patches are often composed of only 

one or a few long-lived genets. New genets establish 

only rarely but once established can apparently 

persist for decades. There is probably little if any 

genet turnover or selection in established patches. 

POLLARD, A. JOSEPH. Department of Botany and 

Microbiology, Oklahoma State University, 

Stillwater, OK 74078. 

- Ecological genetics of the interaction between 

stinging nettles (Urtica dioica) and mammalian 

herbivores. 

Stinging trichomes of Urtica dioica are often 

described as defenses against grazing; however, no 

prior studies have tested this proposition or 

attempted to identify particular herbivores which 

might be deterred. U. dioica is highly variable in 

many respects, including the density of the stinging 

hair investiture. An extreme population of virtually 

stingless plants has been studied intensively. 

Vari'ation in hair density was shown to be continuous, 

genetic, and heritable. Grazing preferences of two 

species of mammalian herbivores (rabbits and sheep) 

were studied under laboratory and field conditions. 

Grazing intensity on a range of genotypes of known 

stinging hair density was compared. Both species 

of herbivores preferentially grazed less well armed 

variants, although there was some indication that the 

two species responded differently. Results suggest 

that the evolutionary consequences of mammalian 

herbivory may be quite different from those brought 

about by invertebrate grazing, which is more often 

studied. 


PRITTS. MARVIN P. and JIM F. HANCOCK. 

Department of Horticulture, Michigan 

State University, East Lansing, MI 48824 

- A comparison of reproductive 

strategies within and between wild 

species of blueberry (Vaccinium in 

Michigan. 

Biomass allocation patterns were determined 

for 12 highbush blueberry plants (V. 

corymbosum) from bogs in southern Michigan, 

and for 10 lowbush plants U. 

angustifolium) in each of 17 diverse 

environments varying in temperature, light, 

moisture, and nutrient availability. With 

the exception of one site which experienced 

a late frost, and another in heavy shade, 

lowbush blueberries did not differ in 

annual allocation to leaves (23.07.), stems 

(9.9.), underground tissues (25.5X) or 

fruits (41.67.). Differences in new ramet 

production were observed however, and were 

correlated with light availability (r=.756, 

p997. of the variability 

in leaf, cane, and root biomass over a 500- 

fold range of plant sizes. On the average, 

highbush reproductive allocation (46.27.) 

was similar to lowbush plants (41.67.), but 

was quite variable and appeared to be 

associated with pollination. Analysis of 

yield components suggest that different 

life history strategies have occurred under 

divergent selection pressures, both within 

and between species of Vaccinium. 

RITCHIE, J.C. Scarborough College, University of 

Toronto, 1265 Military Trail, Toronto MlC 1A4, 

Canada. - Late Holocene pollen evidence for 

deforestation in the High Plains of Algeria. 

A core of marsh sediment from a site in the Telidjene 

valley, 40 km west of Tebessa, yielded a radiocarbon- 

dated sequence of pollen. The area has over 200 mm 

annual precipitation. A treeless steppe, dominated 

by Artemisia-Stipa occupies upland sites. The pollen 

record supports the hypothesis of Le Houerou that the 

steppe is of anthropogenic origin. From 6000 to 2000 

yr the spectra are dominated by Pinus with Ephedra, 

Juniperus and Quercus. The modern pollen assemblage, 

dominated by Artemisia and grass, was established 

abruptly at 2000 yr BP. A short phase of Olea pollen 

near this pollen zone boundary marks the widespread 

olive cultivation of the Roman occupation. Independent 

palaeoclimatic data indicate only minor climate change 

during the past 3000 yr, inadequate to explain the 

major shift in vegetation. 

ROBERTS, B.A. and A.W. ROBERTSON. Nfld. Forest 

Res. Centre, Canadian Forestry Service, P.O. Box 

6028, St. John's, Nfld., AIC 5X8. 

- Atlantic salt marshes 

This paper reviews current research on the Atlantic 

salt marshes of Eastern Canada. Specifically, this 

paper discusses salt marshes in the transition zone 

between the Subarctic and the Boreal phytogeographic 

regions. These salt marshes are also the northern 

limit of many temperate species partly due to


anthropogenic influences. The floristics, the 

habitats and biophysical aspects of the Atlantic 

marshes are described. Aspects relating to anthro- 

pogenic influences on the Atlantic marshes are 

discussed in the context of archeology, contemporary 

rural settlement and vulnerability to offshore oil 

development. Guidelines for environment management, 

protection and rehabilitation research are pnoposed. 

Such guidelines are deemed important since more than 

half the 33 000 ha of salt marshes in Nova Scotia 

have been dyked for agriculture. Most of the salt 

marsh habitats in Newfoundland have a high degree 

of domestic grazing even though the marshes are 

small in size and rare in occurrence. The least 

disturbed in terms of domestic use are the 

Labrador salt marshes which although grazed by 

migratory ducks and geese have not yet been influ- 

enced by man's activities. In addition, the 

Labrador salt marshes are discussed and compared 

to the northern marshes of Arctic Canada in terms 

of their ecology and development. 

ROCK, BARRETT N. Geobotany and Renewable 

Resources, 

CA 91109. 

Jet Propulsion Laboratory, Pasadena, 

- Mapping of deciduous forest cover 

using airborne 

data. 

thematic mapper simulator (TMlS) 

Highly accurate vegetation maps have been produced 

using an airborne version of the advanced multispectral 

scanner (Thematic Mapper) on board Landsat 

4. The area mapped is in the eastern panhandle of 

West Virginia. Data were acquired on October 21, 

1980, at the peak of fall foliage display. The 

vegetation maps were prepared using the VICAR 

FASTCLAS supervised classification program developed 

by JPL. A total of 35 training areas, identified 

on the basis of false color IR photography 

(aerial and ground) and ground observation (0.1 

acre circular plot analyses) were used to produce 

the supervised classification images. Raw bands 

(TMS) used to produce the images were: band 3 (.63- 

.69 in), band 4 (.76-.90 m), band 5 (1.00-1.30 

un), and band 6 (1.55-1.75 Vjn). A total of 10 

vegetation classes are recognized. In terms of correct 

classification of tree species and species 

associations, the images are approximately 90% 

accurate (based on ground checks). 

Ruess, Roger W. Biology research labs, Syracuse 

University, Syracuse, NY 13210, and M.A.K. Lodhi, 

Dept. of Biology, Forest Park College, St. Louis, 

Mo. 63110. Variation in soil nitrification, 

nitrifiers and leaf nitrate, reductase activity in 

selected tree species in a forest community. 

Five different tree species and associated soil were 

studied in a forest community to determine the 

ecological function(s) as related to nitrification, 

nitrifiers, leaf NRA and total leaf nitrogen. Soil 

NH4-N was always higher than the N03-N under all tree 

species, with the exception of Basswood where N03-N 

was almost three times higher than the NH4-N. 

Further, Nitrosomonas and Nitrobacter counts were 

higher under Basswood than any other tree stand. 

Leaf nitrate reductase activity was significantly 

correlated (P .ool) with the soil NO 2-N under all 

five tree stands. Leaf NRA was 20-50 times higher in 

Basswood than in hemlock, Beech, Maple and Oak 

species. Similarly, dry leaf nitrogen was highest in 

Basswood than all other species studied. Our data 

supports that low nitrification, nitrifiers and leaf 

NRA are variably influenced by the indivisulistic 

pressure exerted by different tree species to con- 

serve energy by inhibiting soil nitrification, thus 

avoiding the reduction of leaf N03-N into NH4-N. 

Consequently, species will absorb readily available 

NH4-N, which can incorporate directly in the synthe- 

size of amino acids. However, Basswood is an excep- 

tion to the case which accumulated a large amount of 

leaf nitrogen (5.0%) in very early growing period. 

We suspect that such a rapid nitrogen accumulation 

could not be only due to relatively high nitrification 

but due to a parallel absorption of NH4, NO3 and 

possibly a function of mycorrhizael infection. 

SCHWARZ, A.G.* AND R.E. REDMANN. Department of 

Crop Science and Plant Ecology, University of 

Saskatchewan, Saskatoon, Sask. S7N OWO. 

- Phenology of northern halophytic C3 and grasses. 

C4 

In Saskatchewan, C3 and C4 species coexist in saline 

habitats. The phenology of Agropyron trachycaulum 

(C3), Spartina gracilis (C4) , Puccinellia nuttaliana 

(C3), and Distichlis stricta (C ) was studied from 

May to September. Observations of growth stage, 

height, number of leaves, and number of tillers were 

made on twenty individuals of each population. Environmental 

measurements included air and soil temperatures, 

rainfall, soil water content, and salinity. 

Spring regrowth began earlier in C3 plants than in 

C4 plants. Species from the strongly saline vegetation 

zone (P. nuttalliana and D. stricta) began 

flowering earlier than species from the moderately 

saline vegetation zone (A. trachycaulum and S. 

gracilis). Within both zones, flowering of C3 and C 

3 4 

species was essentially simultaneous. New growth 

occurred in autumn among the C3 plants. Distinct 

temporal separation of the C and C4 grasses 

3 4 

probably is impossible, because of the relatively 

short growing season. 

SELTER, CAROL M.* and WANNA 

D. PITTS. Department 

of Biology, San Jose State University, San Jose, 

CA 95112. 

- Site microenvironment characteristics and seed- 

ling survival of Shasta Red Fir (Abies magnifica 

var. shastensis). 

Distribution of newly established red fir seedlings 

is generally patchy. Areas of regeneration lie side- 

by-side with apparently similar areas where estab- 

lishment has not occurred. To differentiate estab- 

lishment from non-establishment conditions, adjoining 

paired plots (with and without the youngest estab- 

lished seedlings) were sited at six locations in the 

northern California Coast Ranges. Plots were exa- 

mined for differences in duration and character of 

insolation, soil temperatures and moisture content, 

litter depth and composition, and physical charac- 

teristics. Plots without established seedlings were 

distinguished by long midday periods of full sunlight 

along with high surface temperatures. By contrast, 

establishment plots generally received more insola- 

tion in the form of dappled sunlight and experienced 

lower surface temperatures. Other attributes were 

more variable. Patterns of one season' s seedling 

mortality were consistent with these differences, 

and suggest that patchiness may be the result of 

death in midsummer of seedlings in sunny microsites.

SEMPLE, KATHLEEN S. Department of E.P.O.. Biology, 

University of Colorado, Boulder, CO 80309. 

-Relationships among age, size, and reproductive 

patterns in Engelmann spruce. 

Age and size structure and reproductive patterns 

were measured in Picea engelmannii (Engelmann spruce) 

as part of a study on the reproductive biology of 

subalpine forest trees in Colorado. A nondestructive 

method was developed for aging seedlings, using 

height, diameter, and number of branch whorls in a 

predictive equation. Ages of adult trees were 

measured by coring. Age analyses indicated that the 

two populations studied are self-maincaining. Seedlings 

were common and there was an approximately 

uniform distribution of individuals in age classes 

of mature trees (75-325 years old). Height and 

diameter were highly correlated with age in seedlings, 

but not in mature trees. Trees reproducing 

by seed had significantly larger heights and diameters 

than trees that reproduced vegetatively or not 

at all. Numbers of seed produced and seed size were 

also correlated with tree size and age. Size, 

rather than age appears to be the better predictor 

of reproductive status in Engelmann spruce. 

SOHLBERG E.H.* & L.C.BLISS. Dept. of Botany KB-1S 

University of Washington, Seattle WA 98195 

- Interactions between moss and a vascular plant 

species (Ranunculus sabinei) in a High Arctic 

meadow. 

Small vascular plants grow nearly embedded in moss 

mats in moist polar semi-desert plant communities. 

Interactions between a species of vascular plant, 

(R. sabinei) and the moss were examined at King 

Christian Island N.W.T., Canada (77`45'N, 101o01'W) 

Effect of moss presence on R. sabinei was tested 

by clipping 

R. sabinei. 

and removing moss in plots 

Phenology and aboveground 

containing 

production of 

experimental and control R. sabinei plants were 

recorded through two growing seasons. 

Significantly (p4 .05) higher mean maximum 

aboveground biomass of R. sabinei was found for 

no-moss plants vs controls in the second year after 

treatment. Increased rooting zone temperature 

(0.5-1.0?C) in no-moss plots accounts for some of 

the R. sabinei response. Increased soil nutrients 

due to factors including competition effects from 

mosses may have accounted for most ot the increase 

in R. sabinei productivity. 

SPIRA, TIMOTHY P. Department of Botany, University 

of California, Berkeley, California 94720 

-What limits seed production in the alpine perennial, 

Gentiana newberryi (Gentianaceae)? 

Fruit and seed production in the alpine perennial 

Gentiana newberryi (Gentianaceae) were extremely low 

during three consecutive years in the White Mountains 

of California. The removal of flowers by herbivores 

and the availability of pollinators reduce the reproductive 

potential of this species. An additional 

factor is an unusually late flowering period. Whilu 

inflorescences of G. newberryi are present early in 

the growing season, anthesis does not occur until 

late in the season, and flowers often fail to mature 

fruits and seeds prior to the onset of winter conditions. 

An explanation which may account for the late 

flowering period in this species is that available 

resources are utilized to fill vegetative sinks prior 

to reproductive functions. 


SQUIERS, tDWIN R. Departments of Biology 

and Environmental Science, Taylor Univer- 

sity, Upland, IN - An Analysis of the 

Community Gradient Between an Aspen - 

Maple Up'land For'es't' 'and an Alder - Cedar 

Swamp For'est in Northern Lower Michigan. 

The structure of the plant community in the 

ecotone between an aspen - maple upland 

forest and an alder - cedar swamp forest was 

studied at the Grass River Natural Area, 

Antrim County, Michigan. Basal area, den- 

sity, and frequency data were collected by 

taxonomic species from circular quadrats of 

100 square meters each, spaced at 30 meter 

intervals along six parallel transects be- 

tween the two community types. Elevation 

and depth to ground water was also recorded 

at each quadrat. The ecological distance 

between quadrats was assessed using a varie- 

ty of indices of diversity and community 

similarity, Bray-Curtis ordination, and 

principle component analysis. Microcomputer 

generated 3-dimensional graphics were used 

to aid in data display and interpretation. 

The results indicate that the changes along 

the ecocline are complex and species 

specific with dominant species such as 

large-toothed aspen, northern white cedar, 

and braken fern displaying relatively sharp 

distributional boundaries while the abun- 

dance of many of subdominants changes very 

gradually. 

STAIRS, FELICITE and M. A. MAUN. Department of 

Plant Sciences, University of Western Ontario, 

London, Ontario N6A 5B7. - Population characteristics 

of Artemisia campestris in 4 sand dune 

hiabitat-s along La1_e Huron. 

Populations of Artemisia campestris a facultative 

polycarpy were studied in 4 habitats in the sand 

dune system at Pinery Provincial Park. The 

presence of facultative polycarpy present in a 

wild population was habitat related and correlated 

with the age specific mortality rate and duration 

of the vegetative phase. Flowering phenology 

differed in both duration and timing of anthesis. 

Rosette size as a predictor of flowering readiness 

was analysed at different periods and was found 

to be habitat specific. Root crown diameter as 

an alternate predictor was also examined. 

Germination patterns differed between habitats and 

years. A high variance within the pattern was 

correlated with the absence of polycarpy and a 

high mortality rate for all age groups. 

STEWART, COLIN C.* and BILL FREEDMAN, Biology 

Dept. and Institute for Resource and Environ- 

mental Studies, Dalhousie University, Halifax, 

Nova Scotia, B3H 4J1 

- Comparison of aquatic macrophyte communities 

in two small oligotrophic lakes in Kejimkujik 

National Park, Nova Scotia. 

The aquatic macrophytes of two small oligotrophic 

lakes are compared. Beaverskin Lake (50 ha, pH 5.4, 

1.25 Hazen units) and Pebbleloggitch Lake (33 ha, pH 

4.5, 80 Hazen units) are remote headwater lakes with- 

in 2 km of each other. The major macrophyte commun- 

ities for each lake have been mapped and standing 

crops determined. Beaverskin Lake has several spec-


ies, including Potamogeton confervoides, Ranunculus 

reptans and Myriophyllum tenellum, that are not found 

in Pebbleloggitch. Botlh lakes have Eriocaulon sept- 

angulare dominated communities as well as Scirpus 

subterminalis - Utricularia spp dominated areeas. A 

Sphagnum community occupies shallow bays in Pebble- 

loggitch, whereas Sphagnum forms a deepwater (ca 6 m) 

community in Beaverskin. The floating-leaved commun- 

ities in Beaverskin are dominated by Nymphoides cord- 

ata, whereas Pebbleloggitch has large area of Nuphar 

variegatum. As both lakes are receiving acidic depos- 

ition (the weighted annual meanprecipitation pH is 

4.6), this study provid!es a baseline for assessing 

future changes. 

STEWART, JIM D. and BILL FREEDMAN Biology Dept., 

Dalhousie University, Halifax, Nova Scotia, B3H4J1 

-Patterns of biomass allocation among a group of 

sympatric species of Saxifraga in the high Arctic. 

The within-plant allocation of biomass was investigated 

for four species of Saxifraga, growing on 

Ellesmere Island, N.W.T., Canada. Populations of 

Saxifraga cernua, S. nivalis, S. rivularis, and S. 

tricuspidata were observed and subsamples harvested 

seasonally, in 1981 and 1982. At mid-season, the drysite 

evergreen S. tricuspidata had ca. 75% of its 

aboveground biomass as attached dead material, ca. 

10% as foliage, and ca. 3% as reproductive organs. 

The mesophytic evergreen S. nivalis allocated ca. 30%, 

15%, and 20% to dead material, foliage, and reproductive 

organs, respectively. The mesophytic summergreen 

S. rivularis allocated ca. 25%, 30%, and 35%, respectively; 

while the hygrophytic summnergreen S. cernua 

allocated ca. 35%, 30%, and 25%, respectively. Their 

respective allocations to roots were ca. 75%, 30%, 

25%, and 35% (percent total aboveground biomass). 

These allocation patterns follow trends observed in 

temperate plants, but with modifications due to Arctic 

conditions where the principal cause of mortality is 

the severe 

minimal. 

environment, and competition effects are 

SUFFLING, ROGER. F[aculty of Environ- 

mental Studies, University of Waterloo, 

Waterloo, Ontario N2L 3GI. 

- Incidence of fire during succession 

forests.? 

For many landscapes, log ecosystem area 

of a given age since last disturbance may 

be plotted against age to give a polygon 

analogous to the survivorship curve of 

population biology. Its shape indicates 

whether disturbance is more likely in 

early than in late succession. Log area 

versus age polygons were plotted for 2I 

fire-prone Lfntario landscapes, using 

forest resource inventory data. In most 

cases there is an equal chance of 

disturbance relative to age in stands older 

than 50 years, but recent fire control 

obscures the trends in younger stands. 

A more detailed reconstruction of a pre- 

fire control northwest Ontario landscape 

indicates a fire-resistant period in early 

succession, and then an equal chance of 

fire in older stands. The fire resistant 

period is longer in swamp forests than 

in upland sites. 

TAYLOR*, GREGORY J., and ADELE A. CROWDER. 

Department of Biology, Queen's University, 

Kingston, Ontario, K7L 3N6. 

- Uptake and accumulation of copper, nickel 

iron by Typha latifolia L. grown in solution 

culture. 

and 

Concentrations of Cu, Ni and Fe in leaf and root 

tissue of Typha latifolia grown in a syries of solution-iultures 

containing 5 1 100 ug g Cu, 10 - 150 

ug g Ni, or 10 -100 ug g Fe were correlated with 

concentrations of the same metals in the growth 

medium. In contrast to plants growing in contaminated 

wetlands near Sudbury, Ontario, plants grown in 

solution culture were unable to minimize entry of Cu 

and Ni into 

accumulated 

leaf tissue. Leaves of T. latifolia 

-1 

467 + 50 ug g Ni and did not show 

toxicity symptrms. 

Leaf Cu concentrations reached 

127 + 28 ug g and toxicity symptoms (reduced leaf 

elongation and biomass production) appeared at leaf 

Cu concentrations of approximately 80 ug g . Thus 

exclusion of Cu and Ni from above ground tissues 

would appear to be a phenomena related to growth in 

the field, and T. latifolia would appe-ar to have 

internal Cu and Ni tolerance mechanisms. 

THOMAS, A. GORDON* and GARRY BOWES. Agriculture 

Canada, Research Station, Box 440, Regina, Sask. 

S4P 3A2 - Germination patterns in Euphorbia esula 

L. using a 100-cell seed germinator. 

The germination of E. esula seeds in response to 

constant and alternating temperatures was studied 

using a 100-cell germinator. This equipment is a 

new design with 100 independently controlled germin- 

ation cells, each of which hods one standard 100 mm 

petri dish. Temperatures were set to include all 

combinations between O? and 450C in 5?C increments. 

The equipment proved valuable for describing the 

total germination pattern of E. esula. Germination 

failed when daily maximum temperatures were below 

15?C and daily minimum temperatures were above 35?C. 

Seeds from cells with a maximum temperature below 

15?C germinated when transferred to a germination 

cabinet set at 30/10?C. Daily minimum temperatures 

above 4O0C were lethal. Maximum germination occurred 

when (1) the temperature for part of the diurnal 

cycle was between 15 and 350C, (2) the average daily 

temperature ranged from 22 to 270C and (3) the daily 

temperature difference was 15 to 200C. 

UNGAR, IRWIN A. Department of Botany, Ohio 

University, Athens, Ohio 45701. - Factors 

influencing growth and survival in populations of 

Atriplex triangularis. 

Studies were conducted to determine the effects of 

biotic interference and salinity stress on the sur- 

vival of Atriplex triangularis in an Ohio inland salt 

marsh. Transplants of soil cores containing ten A. 

triangularis plants that were put into hypersaline 

environments had very high plant mortality. Plants 

transferred into cleared plots in less saline zones 

showed optimal growth. Thinning experiments indi- 

cated that high plant densities, 50 to 100 plants per 

100 cm2, caused a reduction in dry weight production 

equal to about 80% of single plant controls. Mortal- 

ity was not directly related to plant density levels, 

but was strongly affected by increasing salinity 

stress. Laboratory studies indicated that salinity 

concentrations above 1% NaCl were inhibitory to both 

seed germination and growth of A. triangularis 

plants. The quantity of seeds produced per plant 

showed a positive linear relationship (P

VINCENT, G. and Y. BERGERON. Jardin botanique de 

la Ville de Montreal, 4101 est, rue Sherbrooke, 

Montreal, Que6. HlX 2B2 and Centre de Recherches 

Ecologiques de Montreal, 5858 Chemin de la Cote 

des Neiges, C.P. 6128, Succ. "A" Montreal, Que. 

H3C 3J7. - Plant community pattern analysis in La- 

ke of Two Mountains area (Quebec). 

Following quantitative sampling of riparian and fo- 

rest plant communities bordering on Lake of Two Moun- 

tains, a classification and a plant community pattern 

analysis have been made. In a first step, a communi- 

ty classification was established by using ordination 

and hierarchic agglomeration cluster analysis techni- 

ques. Phytosociological types were distinguished a- 

mong forest communities dominated by Sugar Maple, 

White Pine, Red Ash, Red Oak, etc. and among typical 

shrubby and herbaceous shore communities. The so- 

defined communities have been mapped at a 1:10,000 

scale. As a second step, by superposing on this map, 

soil and topographic maps of the same region, a sys- 

tematic sampling was made. The sampling analysis, by 

means of information theory, makes possible the eva- 

luation of the abiotic variables which most control 

the plant community pattern distribution in this 

area. 

WHIGHAM, DENNIS F. Chesapeake Bay Center for 

Environmental Studies, Smithsonian Institution, 

Edgewater, MD 21037 - Biomass and nutrient allocation 

of Tipularia discolor (Orchidaceae). 

Biomass and nutrient allocation patterns in Tipularia 

discolor (Orchidaceae) were studied in a deciduous 

forest in Maryland. Plants were sampled to determine 

how biomass and nutrients were allocated to different 

plant structures during an annual cycle. Corms older 

that 1 year lose weight gradually during the year and 

most new vegetative growth goes into current year 

corms and leaves. Sexual reproductive structures, 

and similarly leaves, account for a maximum of 

approximately 20% of the total plant biomass. The 

largest percentages of macronutrients (N, P, Mg, Ca, 

K) and micronutrients (Fe, Al, B, Sr, Pb) were found 

in corms 2 years and older, and nutrient concentrations 

were also high in newly formed leaves,-and 

inflorescences. Analyses of the biomass and nutrient 

data suggest that translocation is important, but 

that it does not account for all of the uptake in new 

growth. Plants must, therefore, assimilate nutrients 


DHARMAWARDHAN, SURANGANIE*, MICHAEL S. STRAUSS 

and DANIEL C. SCHEIRER. Department of Biology, 

Northeastern University, Boston, MA 02115. 

Anatomical and Histochemical changes accompanyinggermination 

Schott. 

in taro, Colocasia esculenta (L.) 

The changes accompanying germinating taro, Colocasia 

esculenta (L.) Schott cv PD II were examined 

from imbibition to cotyledon emergence. Seeds were 

germinated on sterile vermiculite, harvested every 

two davs and fixed by previously described procedures 

with 3% glutaraldehyde in 0.02 M Hepes buffer, pH 

6.8 and 2% osmium tetroxide. Thick sections were 

ECONOMIC BOTANY SECTION 

Economic Botany Section 57 

from the soil during all periods of growth. The 

importance of large underground storage structures is 

discussed. 

WINN, ALICE A. Kellogg Biological Station, 

Michigan State University, Hickory Corners, MI 

49060.-Differences in seed size and the role of 

seed size in seedling establishment in two popu- 

lations of Prunella vulgaris. 

Differences in seed size within plants, among plants, 

and between populations in Prunella vulgaris have 

been investigated at two sites in Southwest Michigan. 

Plants in a second-growth forest produce larger seeds 

than plants in an old-field population. Within each 

population, seeds produced in terminal inflorescences 

are significantly heavier than those produced in 

axial inflorescences. Under standard conditions in 

the greenhouse, plants from the old-field are smaller, 

produce significantly smaller seeds, and have pro- 

portionately fewer terminal inflorescences than 

plants from the forest. The role of seed size in 

determining seedling emergence and survival in the 

field has been investigated in each population. 

Differences between populations in the number and 

sizes of seeds produced will be related to between- 

site differences in the pattern of seedling success. 

WINTERHALDER,KEITH. Department of Biology, 

Laurentian University, Sudbury, Ontario P3E 2C6. 

-Metal-calcium-pH interactions affecting germination 

and early growth of Aqrosttis qigantea 

Roth, and their significance on acid, metalcontaminated 

soils of the Sudbury region, Ontario. 

Ions of aluminum, copper and nickel applied singly 

and in combination to germinating grains of Agrostis 

gigantea have a differential inhibitory effect on 

germination, root growth and leaf growth. Metals in 

combination work synergistically with respect to 

inhibition, except in the case of the aluminumnickel 

interaction, in which case aluminum ions 

reduce the inhibitory effects of nickel ions.Calcium 

in the form of sulphate has a small ameliorative 

effect on metal toxicity, while calcium carbonate 

is a highly effective ameliorant. Results are 

discussed in the context of factors limiting natural 

and assisted recolonization of Sudbury area soils, 

in which all three metals occur at toxic levels. 

stained with toluidine blue, periodic acid-Schiffs, 

sudan III or anilene blue for histochemical study. 

Previous work has shown the presence of an aleurone 

layer, prior to imbibition, which reacts positively 

for protein and lipid. As the cotyledon expands 

aleurone cells become flattened and stain weakly for 

protein or lipid. A few cells near the root-hypocotyl 

interface appear larger and react positively to 

sudan III stain. Such cells in other species have 

been termed aleurone transfer cells. The endosperm 

remains rich in carbohydrate with the exception of a 

2-4 cell deep area surrounding the embryo. These 

show considerable decrease in PAS reactivity. At 

approximately 4-7 days the radicle emerges and is 

soon followed by the expanding, bilobed, cotyledon.

58 Economic Botany Section 

STERN, BARRY D. and MICHAEL S. STRAUSS.* 

Department of Biology, Northeastern University, 

Boston, MA 02115. - Density, distribution and 

structure of stomata of taro, Colocasia esculenta 

(L.) Schott, Araceae. 

Taro, Colocasia esculenta (L.) Schott, Araceae, is 

cultivated for its corm in the tropics and subtropics. 

Before the present study few articles 

dealt with its anatomy. An early work was concerned 

with the density of stomata. Our study is 

focused on the anatomy of taro, with emphasis on 

stomatal distribution and structure. Stomatal 

density was determined for C. esculenta cvs. Akado, 

Bun long, Ex. Florida, Lehua. Moi, and Taro hoia 

by examining replicas of the adaxial and abaxial 

surfaces of the leaf. Distribution for C. 

esculenta cv. Bun long was also determined. Leaves 

of C. esculenta cv. Bun long were fixed in 3% 

glutaraldehyde in 0.02 M, pH 6.8, Hepes buffer; 

postfixed in osmium tetroxide, and embedded in 

Spurr's embedding medium. Sections were examined 

by light and electron microscopy. The density of 

stomata was greater than that previously reported 

for the blade. A large variation was found between 

cultivars as well as between individual plants of 

C. esculenta cv. Bun long. The petiole of C. 

esculenta cv. Bun long had one hundredth as many 

stomata as the blade. Little difference was seen 

for the older leaves. The structure of stomata 

differs from monocot stomata previously examined and 

is similar to that of dicots. 


8RETTING, 8. K. Natural History Division, 

Institute of Jamaica, 12 East St., Kingston, 

Jamaica.-Gneric relatonshis in-e Maryiaceae 

and their implications for economic botany. 

Generic relationships in the Martyniacease have been 

problematic. My research reveals that Proboscidea 

and Ibicella share a nearly identical pollen topo- 

graphy, a very similar floral morphology (melitto- 

philous), and dehiscent fruits containing many seeds 

with corky testae and 'firm' embryos. The pollen 

topography and floral morphology of Martynia are 

somewhat similar to the former genera, but Martynia 

bears two rather than four fertile stamens. Inde- 

hiscent fruits containing fewer than 10 seeds with 

papery testae and 'crumbly' embryos distinguish 

Martynia from the former genara, but ally it with 

Craniolaria, whose pollen topography and sphingid- 

pollinated flowers are unique in the family. These 

findings are potentially valuable for economic 

botanists. Species of Proboscidea show promise as 

oilseed crops for aridlands: species of Ibicella 

with similar seeds should also be investigated in 

this regard. Evidently, spacies of Craniolaria 

have roots with medicinal value; hence Martynia 

should also be examined pharmacologically. 

FRYXELL, PAUL A. U.S.D.A., Texas A&M University, 

COLLEGE STATION, TX 77843. Floral symmetry and 

zygomorphy in this Malvaceae. 

Flowers of the Malvaceae are typically actinomorphic, 

with radial symmetry. The petals are individually 

more or less asymmetrical, giving the corolla a 

"pinwheel" appearance. The five imbricate petals 

may overlap in a left-handed or right-handed manner 

(i.e. clockwise or counterclockwise). Studies have 

shown that in most species, flowers of an individual 

plant are about 50% of each type, that is the direct- 

ion of aestivation is random. In a few species, how- 

ever, the direction of aestivation is evidently non- 

random, although the significance of this phenomenon 

is not clear. In typically actinomorphic malvaceous 

flowers, other flower parts (calyx, androecium, 

gynoecium) are symmetrical -- with the exception of 

the genus Abelmoschus in which the calyx splits 

laterally to an asymmetrical form; the flowers of 

Abelmoschus are otherwise radially symmetrical. A 

small number of species of Malvaceae, however, have 

developed a more or less zygmorphic (i.e. bilater- 

ally symmetrical) form. This development of zygo- 

morphy is correlated with floral presentation and is 

presumably also correlated with pollinating animals, 

although observations on pollinators are scarce. In 

these cases, all flower parts (sometimes with the 

exception of the calyx) show bilateral symmetry, i.e. 

the flowers as a whole are zygomorphic. Three dis- 

tinct patterns of zygomorphy have been observed. Two 

of these have evidently occurred only once each (in 

Hibiscadelphus spp. and in Periptera sp. nov.), 

whereas the third has evidently occurred repeatedly 

in several different genera (e.g. Pavonia, Hibiscus, 

Kosteletzkya). As might be expected, zygomorphy 

tends to occur in species with relatively showy 

flowers. 

* 

JAROSZ, ANDREW M. and MORRIS LEVY. Department of 

Biological Sciences, Purdue University, West 

Lafayette, Indiana 47907. - The Phlox-Erysiphe 

cichoracearum interaction: influences of phylogeny 

and ecogeography on patterns of host resistance. 

Host resistance patterns in natural plant-pathogen 

systems are little studied. They are postulated to 

be much different than the homogeneous and speciesspecific 

patterns that are hallmarks in agriculture. 

Patterns of resistance to an Indiana isolate of E. 

cichoracearum, an obligate fungal pathogen causing a 

powdery mildew disease, were determined for ten feral 

Phlox taxa. A total of 866 plants from 113 populations 

were inoculated and scored for the severity of 

infection after 2 weeks. Host responses were examined 

for correlates with phylogenetic and ecogeographic 

factors. The Indiana pathogen isolate can infect 

some plants in all host taxa; this contrasts with the 

extreme specialization in agricultural systems. 

Resistance polymorphisms occur in all taxa but the 

pattern of resistance does not parallel host phylogenetic 

relationships nor is it correlated with 

ploidy level. The level of resistance within populations 

is best correlated with habitat. Populations 

from forest sites tend to be more resistant than 

exposed site populations. Apparently, forest microclimates 

are more conducive for E. cichoracearum 

growth which increases selection favoring resistant 

individuals. One hundred host plants were subsequently 

reinfected with an E. cichoracearum isolate 

of Louisiana origin. Although ca. 25% of the plants 

exhibit differential responses to the two pathogen 

isolates, the overall resistance patterns are not 

significantly different. Thus, despite pathogen 

variability, habitat features remain the strongest 

proximate determinant of host resistance patterns. 

KENNEALLY, KEVIN F.* and EDWARD L. SCHNEIDER, 

Western Australian Herbarium, South Perth, 

Western Australia 6151, and Department of Biology, 

Southwest Texas State University, San Marcos, TX 

78666. - The genus Ondinea (Nymphaeaceae) 

including a new subspecies from the Kimberley 

region, western Australia. 

A new subspecies, Ondinea purpurea den Hartog subsp. 

petaloidea, has been recently discovered. The

occurrence of previously unreported petaloid flowers 

in the gunus and the discovery of seedlings neces- 

sitates expanding the species description. The 

gradation from sepals to petals to petaloid stamens 

to conventional stamens provides additional morpho- 

logical data to support the placement of Ondinea in 

the Nymphaeaceae sensu stricto. 

KNAPP, SANDRA. L. H. Bailey Hortorium, 

Cornell University, Ithaca, New York 

14853. - Biogeographic patterns in Solanum 

section Geminata. 

The members of Solanum section Geminata are 

shrubs and small trees found in the 

understory of primary rainforest and 

secondary vegetation. The section is unusual 

in that many of its species grow in primary 

forest habitats. Species in section Geminata 

occur from southern Mexico to northern 

Argentina. No one species occupies the 

entire range, but several widespread and 

variable species do occur. Principal centers 

of species diversity are: 1) southern Mexico 

to Costa Rica, 2) the eastern Andean slope 

in northwestern South America (primarily 

Colombia), and 3) southeastern Brazil. This 

circum-Amazonian distribution is common in 

Solanum. Closely related species in section 

Geminata generally occur sympatrically 

within centers of diversity rather than 

allopatrically between centers. Several 

widespread species occur in northwestern 

South America and Central America, 

indicating a close connection between the 

two areas. No close species relationships 

appear to exist between northwestern South 

America and southeastern Brazil. Many of the 

species of section Geminata with more 

restricted ranges occur in some of the 

postulated Pleistocene rainforest refugia. 

This biogeographic pattern will be 

considered with respect to the distribution 

of primary forest species of section 

Geminata. 

KRESS, W. JOHN. Department of Botany, 

Duke University, Durham, NC 27706. 

- Adaptive differences in the floral biology of 

Old and New World species of H-eliconia. 

Heliconia is an example of a banana relative that 

has undergone evolutionary modification of repro- 

ductive characteristics in response to different 

pollinators. The great majority of the species are 

found in the American tropics and they all have 

brightly colored inflorescenes. The short-lived 

flowers are open during the day and are pollinated 

exclusively by hummingbirds. A small disjunct 

group of heliconias are native to the South Pacific 

Islands of Melanisia. The inflorescenes of the Old 

World species are dull green and the flowers are 

nocturnal. These features are similar to sympatric 

species of the wild banana that are known to be 

pollinated by macroglossine bats. This paper 

presents the results of field research in Central 

America and the South Pacific and develops a 

hypothesis on the derivation and spread of the 

Old World introductions. 

Economic Botany Section 59 

LEE, PETER F. Department of Biology, Lakehead 

University, Thunder Bay, Ontario P7B 5E1. 

- Production of wild rice on a seeded lake near 

Ignace, Ontario. 

The objective of this study was to determine the 

factors affecting wild rice production on Oval Lake 

which was uniformly seeded with 2270 kg of wild rice 

seed in the winter of 1979. In the spring the depth 

of the lake was lowered to a mean value of 31 cm. In 

August of 1979, sampling of the lake was done along 

transects for intraspecific competition, interspeci- 

fic competition, sediment pH, nitrogen, phosphorus, 

potassium, calcium, magnesium, iron, manganese, zinc, 

copper and loss on ignition. Utilizing cluster and 

discriminant analyses, the lake was divided into 

production regions. Factors affecting these 

production regions were primarily intraspecific 

competition and organic, phosphorus, and micro- 

nutrient concentrations of the sediment. Trials 

under greenhouse conditions revealed that 

production could be greatly increased with the 

addition of nutrients. Since 1979 other production 

problems including interspecific plant competition, 

seed survival and nutrient depletion have developed. 

Management implications to increas& the commercial 

harvest of approximately 10000 kg per year are 

discussed. 

MISHLER, BRENT D. Farlow Herbarium, Harvard Uni- 

versity, Cambridge, MA 02138 - Phylogenetic rela- 

tionships and generic limits of Tortula (Musci: 

Pottiaceae): evidence from SEM studies of the 

peristome. 

The genus Tortula (Hedw.) has historically been con- 

sidered a "basal" group in the phylogeny of the sub- 

family Pottioideae. Work in progress on the cladis- 

tic relationships of the subfamily, based on a number 

of characters, shows that the genus Tortula (as 

currently delimited) is indeed an artificial, para- 

phyletic group. SEM studies of peristomes have 

yielded a wealth of characters useful in determining 

monophyletic groups at various levels of analysis. 

The presence of a basal membrane is a widespread 

feature, not useful for defining Tortula, or even the 

whole subfamily. However, details of the sculptur- 

ing, position, and arrangement of the cell walls 

making up the basal membrane, particularly the pro- 

tean variation of the fine ornamentation, have proved 

to be useful indicators of relationship. A monophy- 

letic group can be distinguished that roughly corres- 

ponds to the segregate genus Syntrichia Brid. (which, 

however, must be called Tortula because the type 

species of the latter is included), by a suite of 

characters including the high basal membrane with 

its unique fine-scale ornamentation. Other species 

now placed in Tortula seem to be more closely related 

to other genera. 

OKOLI, 'BOSA EBENEZER. Department of Botany, 

University of Port Harcourt, P.M.B. 5323, Port 

Harcourt, Nigeria. - Wild and cultivated cucurbits 

in Nigeria: their uses and economic potentials. 

The family Cucurbitaceae is well-represented in 

Nigeria by about 20 genera and 45 species. It is an 

extremely interesting and unusual family distributed 

largely in the tropics. Most of the species are 

wild but a good number are cultivated. The family 

has perhaps the greatest number of species in 

cul tivation for di verse purposes i n di fferent parts

60 Genetics Section 

of the country. Certain genera such as Telfairia, 

Cucurbita, Citrullus, Cucumeropsis, Cucumis and 

Trichosanthes are cultivated in southern Nigeria 

since their fruits and/or leaves constitute impor- 

tant items in the diet. Other genera are important 

as oil plants, medicinal plants, sources of tanning 

materials, sponges and house-hold utensils. An 

outline biology and potential uses of the lesser 

known indigenous species are discussed. 

PRYER, KATHLEEN M. ,* DONALD M. BRITTON and 

JOHN McNEILL." Department of Biology, 

Uiversity of Ottawa, Ottawa, Ontario, 

Canala, KlN 6N5 and Dej.art Iient of Botany 

aid Geiietics, UiiiversitY of GueOlh, 

Guelph, Oditario, Canada N 1u 2WL - 

SX-ste matic studies in the Ienus 

cVmnocaruLiuat New ul. ( eniaceae) in North 

Am.erica. 

Mor,pholoiica.l, plqtocheh.lical aiid cytolouical 

stu1ies have resultEc in a svstematic 

rovYiSiOIi oFZ tLe Jenus .}7mnocarpium in North 

America. Multivdriato analysis of the 

morp lholojical data supports the recotnitior 

of six taxa A\dditionally, cluster analysis 

and ordination of the ,-hv toche micai ddta 

established that each of these taxa can be. 

recogni-z ed by its chromiatographic prffile 

alonei These data sup)port the recognition 

of ro. boertia.uum anld G. jessoense subsp. 

2 u.1u m as distinct taxa, and the hybrid 

ori irn of G. x intermedium. The 

chroinatojraphic prof ile of G. intermediuni is 

esse-ntial-y a suinmaticn of the profiles of 

its oresuiued rarejot;, drQteris subsp. 

Symposium: Competence, Determination and 

Canalization in Plant Development 

GENETICS SECTION 

INTRODUCTION 

The symposium will focus on the concepts of develop- 

mental genetics and consequent concern with cellular, 

intracellular and molecular events. Current interest 

in such an analytical approach to the study of plant 

development coupled with the experimental questions 

that can now be answered using molecular probes and 

in situ hybridization suggest that this subject area 

will be one of rapid progress and exciting discoveries 

in the next few years. 

Organized by Michael L. Chrsitianson, Zoecon Corpora- 

tion, Palo Alto, CA. 

CHRISTIANSON, MICHAEL L.*, and DEBRA A. WARNICK. 

Department ofNMolecular Biology, Zoecon Corporation, 

Palo Alto, CA 94304. - Competence and determination 

in shoot initiation in vitro by Convolvulus arvensis. 

The process of shoot organogenesis from leaf explants 

in vitro incl udes two events of developmental biology. 

The explants acquire competence, and as a result of 

the induction which ensues, they become determined for 

shoot formation. This latter event precedes the appearance 

of shoot apices in paraffin section. Unlike the 

dlisjunctumi and '. jessoense subsp. 

Ha rvulumn. Scariniiicg electron microscopy was 

used to exa.niiie variationii ni pe rispore 

chaLacters 'hoth withlin acnd between taxa. in 

contrast to previous studies in thie genus, 

spore morjholojy proved to be impractical in 

secies di scriamination, s ince all taxa 

exhibited similar patterns of variation. 

Howev;r, spore size was correlated wit h 

Ploid y level, permittinSJ delimitationi 

be tween the di; loitl and tetrajloid 

subspecies of ". drl ot ris. 

WELLS, ELIZABETH FORTSON. Department of Biological 

Sciences, The George Washington University, 

Washington, D.C. 20052. - Comparative floral development 

ceae). 

in four species of Heuchera (Saxifraga- 

Flower development was studied in four species of 

Heuchera. Mature flowers of the four species differ 

as to size, exsertion of stigmas and anthers, and hypanthium 

length. Flower development is very similar 

among the four species in the very early stages but 

later diverges in several significant ways. A size 

difference is first evident in the undifferentiated 

flower primordium. After sepals, petals, and stamens 

appear, intercalary growth at their base forms a free 

hypanthium, which varies in length and degree of 

asymmetry from species to species and serves as a key 

character in recognizing each species. The major differences 

between the flowers of the four species are 

shown to result from differences in the size of the 

undifferentiated flower primordium and in the onset, 

duration, and asymmetry of intercalary growth. 

developmentally plastic meristemoids in Convolvulus 

arvensis roots in vitro and in vivo, the meristemoids 

formed in callus have unique fates. Culture on shoot- 

inducing medium, SIM, produces cells or groups of cells 

determined specifically for shoot formation; transfers 

from SIM to root-inducing medium, RIM, near the time 

the tissue becomes determined do not lead to root 

formation. In contrast, the competence which explants 

acquire during the first days in culture is general. 

Exposure of explants to SIM, RIM, or simply callus- 

inducing medium, CIM, develops competence for shoot 

induction. Indeed, some genotypes of C. arvensis which 

do not make shoots on SIM, will make shoots when 

culture on SIM is preceded by brief preculture on CIM. 

Varying the amount of preculture on CIM shows that 

the duration and stability of the competent state is 

genotype specific. Extended culture on CIM shows that 

competence is not synonymous with callus initiation 

or growth. 

DAVIDSON, D. Department of Biology, McMaster 

University, Hamilton, Ontario, L8S 4K1. 

- Patterns of cell proliferation and mitotic asym- 

metry in root meristems. 

Meristems are ordered structures: their different 

tissue types form a well defined pattern and their 

overall growth results in increases in cell number 

and cell size along a single axis. This constancy of 

pattern is maintained in spite of the variation, in

different tissues, in the rates, axes and degree of 

asymmetry of cell division. Evidence for such varia- 

tion will be presented and will be related to fluctua- 

tions: 1) in cell cycle duration within individual 

cell lineages; 2) in the orientation of asymmetrical 

divisions. These fluctuations will be shown to occur 

independently even in adjacent columns of cells. 

Division asymmetry produces two nuclei and two cells 

of different sizes; the sister nuclei also differ in 

RNA and protein content and in cell cycle duration. 

Evidence will also be presented for changes in 

nuclear:cytoplasmic ratios in roots of germinating 

seeds. It will be argued that cell cycle duration is 

aphenotypic trait that is plastic, that may vary in- 

dependently of cell size and of the rate of cell 

elongation, and that is regulated, to a large degree, 

autonomously in individual lineages of cells. 

MCDANIEL, CARL N. Department of Biology, 

Rensselaer Polytechnic Institute, Troy, NY 12181. 

Determination for floral development in day- 

neutral tobacco and sunflower. 

Populations of day-neutral tobacco (Nicotiana 

tabacum L.) and sunflower (Helianthus annuus L.) 

plants form reproductive structures after a uniform 

amount of vegetative growth as measured by number of 

nodes (Dev. Biol 66: 250-255; Growth 36: 339-349). 

The total number of nodes produced by the terminal 

meristem of a sunflower plant cannot be increased by 

rooting or grafting. These observations indicate that 

early in development the sunflower meristem becomes 

determined for floral development. In contrast, the 

tobacco terminal meristem can be made to produce 

significantly more nodes by grafting and rooting. By 

continually rooting the terminal portion of theshoot, 

the meristem will remain vegetative indefinitely 

(Planta 148: 462-467). However, during the normal 

course of growth the tobacco meristem does become 

determined to form a flower. This determination is 

not only expressed by axillary buds but also by 

internodal cells. That is, axillary buds near the 

inflorescence exhibit determinant growth and inter- 

nodal cells from the inflorescence can form de novo 

floral buds (Planta 115: 87-92). These two species 

exhibit stable determination for floral development 

but the timing of the determination event is markedly 

different. As a result, two distinct patterns of 

growth are observed. The sunflower has a determinant 

growth pattern which is established prior to or soon 

after germination. The determinant growth pattern of 

tobacco is not initiated until long after germina- 

tion. Although only determination has been considered 

in the above, competence and induction are involved 

in the flowering process and will be considered. 

Support from NSF,PCM 82-04491. 

MUJRRY, LYNN E. Zoecon Corporation, 975 California 

Avenue, Palo Alto, CA 94304. - Competence and determination 

in the developing root epidermis of barley. 

In tissue culture, the term competence describes the 

time after which cells in a callus are responsive to 

changes in the growth medium, i.e., inducible. Once 

physical or chemical induction takes place, certain 

cells organize to become either a root or shoot. The 

term determination defines the latter point beyond 

which induction is irreversible. While these terms 

work well at the organ level of plant organization, 

they may have slightly different meanings when applied 

to developing tissue systems. In the progression of 

cellular events which produces the mature root epidermis, 

competence is assumed to occur in the proximal 

Genetics Section 61 

protoderm whiich gives rise to trichoblasts and atrich- 

oblasts. Trichoblasts are distinguishable in many 

species as short, densely cytoplasmic cells which re- 

sult from an asymmetric cell division, contain eleva- 

ted amounts of nuclear DNA, and give rise to root 

hairs. They represent the cell in which determination 

would normally occur. My data indicates that determin- 

ation is not a single, irreversible event in develop- 

ing epidermal tissues. In Hordeum vulgare Larker, en- 

vironmental influences greatly affect root hair devel- 

opment. Under control conditions, morphological dif- 

ferentiation of trichoblasts proceeds in a timely man- 

ner, and nuclear DNA amounts are double (2C) that 

found in the meristem (1C) of the same root. With 300 

mM NaCl stress, root hair growth and differentiation 

are slow, and differential replication of the DNA is 

suppressed. In 200-300 mM KH2P04, epidermal nuclei 

become increasingly vacuolate, nuclear DNA doubles, 

and root hair differentiation is completely suppressed. 

In barley, epidermal development and differentiation 

requires two commitments, one involving the nuclear 

state and the other, the morphological state. 

SAWHNEY, VIPEN K. Department of Biology, 

University of Saskatchewan, Saskatoon, Sask. S7N 

OWO, Canada - Developmental regulation of a malesterile, 

stamenless-2 mutant of tomato. 

The single gene recessive mutant, stamenless-2 

(sl-2/sl-2), of tomato (Lycopersicon esculentum) 

produces structurally abnormal stamens and non-viable 

pollen. The development of stamens can be regulated 

by plant hormones and temperature conditions. Gibberellic 

acid (GA3) induces the formation of normal 

stamens with viable pollen whereas indole-acetic 

acid (IAA) causes the formation of carpel-like 

structures in place of stamens with no evidence of 

microsporogenesis. Similarly, low temperatures 

(18?C day/15cC night) promote the formation of 

normal stamens, and high temperatures (280C day/230 

C night) induce the formation of carpel-like structures. 

Relative growth studies of stamens and 

timing experiments with GA3 have shown that at the 

time of initiation, the stamen primordia of mutant 

flowers, although morphologically similar to the 

normal, possess some differences from them and that 

their developmental path is not completely fixed 

at this time. Further it was shown that various 

features of stamens are canalised sequentially at 

later stages of development. A comparison of protein 

patterns, by using iso-electric focusing and second 

dimension SDS-PAGE, has shown some differences in 

the mutant and normal stamens. 

WALKER, KEITH A. Plant Genetics, Inc. 

1930 5th Street, Davis, CA., 95616. 

-Modeling morphogenesis. Experimental ap- 

proaches with alfalfa somatic embryogenesis. 

Researchers of the last two decades have devel- 

oped physiological models for the control of in- 

duction and expression of regeneration in cells 

cultured in vitro. Over this time work on asex- 

ual embryogenesis in somatic cell cultures has 

contributed greatly to our current understanding 

of hormonal, nutritional, and environmental fac- 

tors which influence the process. Nevertheless, 

these studies have not led to a deeper under- 

standing of the mechanism underlying those 

forces which shape the development of the em- 

bryo either in vitro or in vi vo. The view is pre- 

sented that to achieve a greater understanding


of the developmental regulation during adventive 

embryogenesis, systems which permit the spacial 

and tempora l separation of induction, determina- 

tion and differentiation processes as well as the 

availability of competent and noncompetent popu- 

lations of cells will be required. In this con- 

text, the suitability of alfalfa somatic embryo- 

genesis as a system for the study of basic devel- 

opmen ta I mechanisms shall be examined. The 

state of knowledge regarding the role of this 

process played by the hormonal factor 2,4-D, 

and other trophic factors shall be presented with 

the goal of suggesting opportunities for future 

research. 

WARNICK, D. A. Department of Molecular Biology, 

Zoecon Corporation, Palo Alto CA 94304. - 

Convolvulus arvensis: Rhizogenesis in vitro. 

Leaf explants of Convolvulus arvensis can produce 

either roots or shoots when cultured on a basal medium 

of Murashige and Skoog salts, vitamins and sucrose 

with the addition of 12 mg/l IBA for root-inducing 

medium, RIM, or 0.05 mg/l IAA and 7.0 mg/l 2-ip for 

shoot-inducing medium, SIM. A screen of 105 seed 

derived individuals from two localities shows that 

root- and shoot-organogenesis are independent phenomena. 

Successive transfers to basal medium show that culture 

on root-inducing medium, RIM, results in the explants 

becoming determined for root formation: development 

proceeds to completion on basal medium. The minimal, 

necessary exposure to RIM is reproducible, genotypespecific 

and varies from 3 to 10 days. Histological 

examination reveals meristemoids at the time of 

determination and that roots arise endogenously in the 

callus produced at the edges of the explant. Despite 

the apparent independence of the ability of explants 

to produce roots on RIM and shoots on SIM, transfer 

experiments find that preculture on SIM can improve 

root formation on RIM. Other experiments show that RIM 

can substitute for SIM during the first few days of 

shoot induction. Description of the similarities and 

differences in the early events of root- and shootorganogenesis 

may be important to achieve whole plant 

regeneration in certain agronom-ically important species. 

Symposium: Developmental Genetics of Higher 

Plants 

FREELING, MICHAEL. Department of Genetics, 

University of California, Berkeley, CA 94720. 

- Developmental consequences of insertions in the 

Adhl gene of maize. 

Almost every gene in higher organisms is regulated 

differentially per tissue or developmental stage; 

maize Adhl is no exception (cf.1). We are trying to 

understand the regulatory properties of Adhl by 

inducing mutants in a known progenitor allele, Adhl-S. 

We then compare mutants and progenitor at every level 

down to nucleotide sequence and sequence arrangement. 

The Adhl variants and mutants that affect ADH expres- 

sion in different organs coordinately are caused by 

small changes at the DNA level. Five independent 

insertions lower or obliterate ADHl expression; all 

are within the about 4 kb transcriptional unit. 

Mutant alleles caused by the insertion of 1.4 kb Mul 

express various, lower mRNA levels (1). The three Mul 

insertion alleles have the element in the first 

intron, but at different sites; one has been located 

to the nucleotide (Bennetzen, Strommer, Taylor and 

Freeling, in preparation). Two other, different 

insertions are transcribed, the message is appropri- 

ately larger than 1650 nt, and these are genetically 

linked to poor transmission through the pollen and, 

in one case, a dominant leaf growth morphology called 

"Knotted". I suspect that some insertions at Adhl, a 

dispensable gene, initiate chromosomal position 

effects on nearby, indispensable genes. 

It may yet be possible to work backwards from 

regulatory mutants to developmental programs. 

(1) Strommer, J. N., S. Hake, J. Bennetzen, W. C. 

Taylor and M. Freeling, 1982. Nature 300:542-544. 

POETHIG, R. SCOTT. Department of Biology, University 

of Pennsylvania, Phildelphia, PA 19104. 

- The use of genetic mosaics for the -analysis of 

plant developrnent. 

Traditional histological techniques provide limited 

information about the cellular dynamics of morphogenesis 

and the fate of initial cells. These morphogenetic 

parameters can be established easily and 

unequivocally, however, from x-ray induced somatic 

sectors (a technique called clonal analysis). Recent 

clonal analyses of leaf morphogenesis in tobacco, and 

of embryogenesis and shoot development in maize, have 

provided dramatically new pictures of these phenomena. 

Clonal patterns in tobacco, for example, demonstrate 

that the leaf is not derived from a small 

group of apical initials as is generally assumed, but 

from a relatively large group of cells, each of which 

contributes to a characteristic section of the leaf. 

Furthermore, there is no evidence for the existence 

of a margirial meristem; the expansion of the lamina 

depends entirely on intercalary growth. Somatic 

sectors induced during the development of the shoot 

apical meristem in maize demonstrate that, like the 

tobacco leaf, it arises from a large group of cells 

each of which has a characteristic (though not determined!) 

fate. Two general conclusions can be drawn 

from these studies: 1) within the constraints 

imposed by their position within a plant, the fate of 

individual cells is variable; and 2) apically situated 

cells in a determinate meristem make only a 

limited contribution to the growth of the meristem. 

SHERIDAN, WILLIAM F. Department of Biology, 

University of North Dakota, Grand Forks, ND 58202 

- Genetic Regulation of Plant Embryogenesis 

Three promising systems for studying the genetic reg- 

ulation of plant embryo development have been report- 

ed. These are the embryo-lethal mutants of Arabi- 

dopsis, the carrot temperature-sensitive variants 

blocked in somatiq embryogenesis and the defective 

kernel (dek) mutants of maize. A model system for a 

genetic analysis of plant embryo development utiliz- 

ing embryo-lethal mutants of Arabidopsis was proposed 

and six nonallelic recessive mutants that were char- 

acteristically arrested at early stages of embryo 

development were described by Meinke and Sussex 

(1979a, b). Recently, the isolation of a number of 

temperature-sensitive carrot cell variants was re- 

ported by Breton and Sung (1982). These variants are 

stable in culture and most are maintained through 

plant regeneration and exhibit the ts trait when put 

back into culture. The variants are blocked at dif- 

ferent stages of development including some that can- 

not grow in embryogenic medium, others than can grow 

only as callus, and others blocked prior to the 

heart stage of embryogenesis. The variants are all 

spontaneous in origin and their stability and temper- 

ature sensitivity are consistent with their being 

mutants. The examination of a large group of de-

fective kernel mutants, representing many gene loci 

(Neuffer and Sheridan 1980), by morphological and 

embryo culture techniques (Sheridan and Neuffer 1980) 

led to the suggestion that many were potential can- 

didates as developmental mutants (Sheridan and 

Neuffer 1981). A group of 20 such mutants were 

identified and examination of mature North Dakota 

grown ears of 17 of these 20 revealed that 14 of 

them were indeed blocked prior to leaf primordia for- 

mation (Sheridan and Neuffer 1982). Recent results 

with these maize mutants will be presented. 

SM I TH, J. D. Plant Sciences Department, Texas A&M 

University, College Station, Texas 77843. 

Regulation of Seed Development in Zea mays. 

The termination of seed development in a dormant 

seed i s so preval ent that it is easy to think of 

dormancy as an obl igatory final stage of seed 

development. However, the existence of viviparous 

seed in a variety of species establishes dormancy as 

an optional rather than obligatory developmental 

stage, and the viviparous mutants of Zea mays 

indicate that the induction of seed dormancy is 

genetically regul ated. Abscisic acid (ABA) is 

unquestionably involved, but its mode of action, the 

cellular reorientations it affects, the ontogenetic 

stage when these events occur, and even its 

biosynthetic pathway have not been def ined . 

Investigations of the viviparous mutants have 

established that the carotenoid-deficient mutants 

are also ABA deficient and the vp mutant, which has 

normal ABA content and is insensitive to exogenous 

ABA, appears to be an ABA-receptor mutant. The 

carotenogenesis inhibitor fluridone indirectly 

inhibits ABA synthesis and induces vivipary if 

applied at the appropriate time. Experiments wi th 

genetical ly and chemically induced viviparous seed 

have el ucidated the ABA biosynthetic pathway, 

defined the ontogenetic stage when the induction of 

dormancy is initiated, and identi fied some of the 

biochemical events that are affected by ABA at this 

time. Supported by USDA CRGO Grant No. 79-59-2485- 

1-1-370-1. 


AMOAH, VICTOR and PAUL GRUN. Department of 

Horticulture, Pennsylvania State University, 

University Park, PA 16802. 

- Maternal regulatory control of yield components 

in Solanum. 

Analyses of yield components of back-cross two 

progenies of S. tuberosum ssp. andigena x ssp. 

tuberosum and (S. phureja x chacoense) x ssp. 

tuberosum showed the presence of significant 

differences between reciprocals. The inheritance 

of the reciprocal differences was not that of 

cytoplasmic factors. They cannot be ascribed to 

the "maternal effect" since the differences were 

maintained over a time period well beyond that 

when contents of the egg contributed by the maternal 

parent would have been diluted by gene products 

of the plant's somatic chromosomes. The phenomenon 

cannot be ascribed to dauermodifications since 

differences between the parents were not environ- 

mentally induced. An interpretation of this 

Genetics Section 63 

phenomenon will be discussed based on a concept 

of maternal regulatory genes. 

HART, GARY E. Department of Plant Sciences, Texas 

A&M University, College Station, TX 77843. 

- Discovery and genetic control of a hexaploid 

wheat NAD-dependent alcohol dehydrogenase which 

acts on aromatic alcohols. 

Genes which encode isozymes are valuable markers for 

the chromosomes and chromosome arms of Triticum 

aestivum (hexaploid wheat, 2n = 6x = 42, genomes 

AABBDD) and its relatives in the Gramineae tribe 

Triticeae. Approximately 80 isozyme genes have 

previously been identified and located in chromosome 

arms in hexaploid wheat cv. Chinese Spring. I report 

here the discovery of a NAD-dependent aryl-alcohol 

dehydrogenase (ADH, E.C. 1.1.1.9Q) which utilizes 

cinnamyl alcohol as a substrate. Analysis of the 

available compensating nullisomic-tetrasomic 

derivatives and the homoeologous chromosome group 6 

ditelosomic strains of Chinese Spring have provided 

strong evidence that this enzyme, which has been 

designated ADH-3, is active as a dimer and is encoded 

by a paralogous set of three genes, designated 

Adh-A3, Adh-B3, and Adh-D3, which are located in 

chromosome arms 6Aq, 6Bq, and 6Dq respectively. 

Orthologous Adh-3 genes have been detected and located 

in chromosomes in Elytrigia elongata (chromosome 

6E), Secale cereale cv. Imperial (6R) and Hordeum 

vulgare cv. Betzes (6H). The Adh-3 genes should 

serve as additional useful markers for group 6 

chromosomes in the Triticeae. 

HENKE, R. R.*, G. L. FOWLER, J. K. THOMPSON and 

B. C. MULLIN. Department of Botany, The University 

of Tennessee, Knoxville, TN 37996-1100. - The 

selection of p-fluorophenylalanine resistant mutants 

in barley. 

Mutagenized M2 populations of barley, Hordeum vulgare 

cv. Atlas 57 were screened for resistance to the 

phenylalanine analog, p-fluorophenylalanine (Pfp). 

The initial selection was carried out by screening 

embryoless halved seeds for the capacity of their 

aleurone tissue to synthesize and release a functional 

a-amylase when incubated in the presence of the 

analog. The a-amylase activity was determined visually 

using a I KI/soluble starch assay. Individual 

half-seeds whe; incubated in the presence of soluble 

potato starch and GA3 under appropriate conditions 

produced sufficient a-amylase to completely hydrolyze 

the starch. This resulted in a clear, yellow-colored 

incubation medium when stained with I KI. Pfp inhibited 

the synthesis of functional a_-aiylase in wild 

type half-seeds resulting in visually distinct blueblack 

color reaction with 12KI/medium color reaction, 

indicating aleurone expression of a functional a-amylase 

in the presence of the inhibitor. Approximately 

14,000 M half-seeds were screened. This resulted in 

the isolation of 186 putative Pfp-resistant mutant 

half-seeds. The embryo-containing portion of these 

half-seeds was grown to maturity and their progeny 

tested for Pfp-resistance. Segregation, in various 

ratios of the mutant trait was observed in the progeny 

of 12 of the parents tested. One of the M 

plants gave rise to progeny that were homozygouS for 

Pfp-resistance and were also homozygous for darkly 

pigmented seeds. This phenotype has remained stable 

through a subsequent generation. Details of the 

screening protocol and some properties of the Pfpresistant 

mutants will be presented.


KOKONTIS, JOHN M. AND E.D. GARBER 

Department of Biology, University of Chicago, 

Chicago, IL 60637 

-Spontaneous and induced mitotic recombination in 

Ustilago violacea detected at the cellular level. 

Spontaneous and induced mitotic recombination in the 

heterobasidiomycete Ustilago violacea was detected at 

the cellular level using the recessive morphological 

mutation "pseudohyphal" (ph). Mitotic recombination 

in a ph+/ph diploid sporidium giving a ph/ph condi- 

tion results in a drastically elongated cell which is 

microscopically distinguishable from ph+/ph cells. 

The percentage of microcolonies (50-100 cells) con- 

taining at least one ph/ph cell is an accurate mea- 

sure of recombination between the ph locus and its 

centromere. Recombination was induced by ultraviolet 

light (UV), nitrogen mustard (NM) and metabolically 

non-activated cyclophosphamide (CP). Spontaneous 

recombination giving a ph/ph cell occurred in 4.1 + 

0.5% of microcolonies. While maximal UV and NM in- 

duction was 85-95%, maximal CP induction of recombi- 

nation was only 6.7%. Low temperature (140C) applied 

after inductive treatment uniformly reduced recombi- 

nation to spontaneous levels, while high temperature 

(300C) increased UV-induced recombination, had no 

effect on NM-induced recombination and reduced CP- 

induced recombination to spontaneous levels. Tempera- 

ture alone had no effect on recombination. UV induc- 

tion of recombination was dependent on the rate of 

cell division; rapidly dividing log-phase cells were 

most sensitive to UV induction of recombination. 

The cellular detection of mitotic recombination is a 

method of assaying post-replication repair of genetic 

damage and a possible screen for agents causing ge- 

netic damage in eukaryotic cells. 

MULCAHY, DAVID L.* AND GABRIELLA B. MULCAHY. 

Department of Botany, 

Amherst, MA 01003. 

University of Massachusetts, 

- Gametophytic self incompatibility reexamined. 

Gametophytic self incompatibility is generally understood 

to involve the active inhibition of self pollen 

tubes by a specific molecule. This is the classical, 

"oppositional model." The model, however, 

to accommodate a number of well established 

is unable 

observations: 

quantitative variation in the incompatibility 

reaction, the activation of new incompatibility 

alleles by inbreeding, the difficulty of mapping the 

S-gene, the inexplicably large numbers of S-alleles 

observed in natural populations, and the presence of 

self compatible individuals among dihaploid derivatives 

of self incompatible plants. Each of these 

anomalies can be explained if we assume that there 

are complementary interactions between pollen tubes 

and the styles. Interesting implications of this 

hypothesis include possible explanations for several 

types of pollen-style interactions presumably not 

relAted to self incompatibility. There is also the 

suggestion that, 

incompatibility, 

with some cases of gametophytic self 

there may be no S-gene, as classically 

envisioned. 

PRICE, H. J., K. CHAMBERS, and K. BACHMANN, Texas 

A&M University, College Station, TX 77843, Oregon 

State University, Corvallis, OR 97331, and 

Heidelberg University, West Germany. - 

Temporal changes in DNA content of Microseris 

douglasii populations. 

Nuclear 2C DNA content of M. douglasii varies over 

20% among plants and by 14Fo among populations. 

High DNA content populations are restricted to more 

mesic sites. A correlation between the amount of 

annual rainfall and DNA content was temporally 

observed within a single site near Jolon, CA, over 

a 15-year interim. Only high DNA content plants 

(ca. 23.50 FAU = Feulgen absorbancy units) were 

found in the 1973 collection prior to the last 

major drought. Only low val ues (ca. 21.50 FAU) 

were found in plants collected in 1977 which marked 

the end of the drought. There have been five 

successive growing seasons with ample rainfall 

beginning 1978. We have sampled several 

populations annually since 1980 to see if high DNA 

content plants increase in frequency over several 

high rainfall years, and decrease durifng successive 

drought years. High DNA content plants comprise 

about 5% and 40%, respectively, of the plants 

measured from the 1980 and 1981 Jolon collections. 

A sample in 1977 from a population near the 

Parkfield-Coalinga Road summit was highly variable 

in DNA content, X = 23.03 ? 1.06 FAU. The 1980 and 

1981 populations were individually fairly uniform 

with respective mean DNA contents of 22.57 ? .21 

and 23.19 ? .23 FAU. Subsequent sampling of these 

populations should allow us to determine whether 

DNA content evolves in response to environmental 

changes. Supported by NSF grant DEB 8009427 and 

the Texas Agricultural Experiment Station. 

UHL, CHARLES H. Section of Plant Biology, Cor- 

nell University, Ithaca, NY 14853. - Preferential 

pairing of chromosomes in hybrids of the Mexican 

Crassulaceae. 

Natural polyploids in the Mexican Crassulaceae appear 

to be autopolyploids, and no plants from the wild 

have yet been definitely identified as allopoly- 

ploids. Hybrids also appear to be very rare in na- 

ture. Nevertheless, hundreds of allopolyploid hy- 

brids (AABB), many of them intergeneric, have been 

produced in cultivation. Parents of most of these 

hybrids had different chromosome numbers, but at mei- 

osis most or all of their chromosomes regularly form 

bivalents only, regardless of the parental chromosome 

numbers, and most such hybrids yield abundant second- 

generation progeny. Evidently pairing here is 

strongly preferential between corresponding chromo- 

somes of two sets received from the same polyploid 

parent (autosyndesis). Appropriate crosses and back- 

crosses have produced second-generation hybrids ha- 

ving one, two, or three sets of chromosomes from an 

original wild tetraploid, with phenotypes to match. 

Second-generation hybrids with a third autotetraploid 

(CCCC) are autoallotetraploids (ABCC) and show simi- 

lar preferential pairing between homologues of the 

two C-genomes. Most aLso show considerable pairing 

between chromosomes of the A and B sets, even where 

they differ in number and failed to pair with each 

other in the F1 (where full homologues were present). 

(Extensive chromosome pairing also characterizes most 

diploid hybrids here, regardless of differences in 

their chromosome numbers.) The basis for the high 

preference and selectivity in chromosome pairing here 

is not known, but the situation seems different from 

the regulated chromosome pairing that is well known, 

for example, in allopolyploids of' wheat.

Special Lecture: Darwin's Beagle Collection 

PORTER, DUNCAN M. Department of Biology, VPI & SU, 

Blacksburg, VA 24061. 

- Darwin's Beagle collections. 

Little has been published on the contents and dispo- 

sition of the plant, animal, and geological collec- 

tions that Charles Darwin gathered on the voyage of 

HMS Beagle. There are many clues in the contemporary 

papers published on the various groups by John Gould, 

George Waterhouse, Francis Walker, Adam White, and 

Darwin himself, but little of this information has 

penetrated into the modern literature. Unpublished 

notes in the Darwin Archives at the Cambridge Univer- 

sity Library, at Down House, and at the British Muse- 

um (Natural History) provide more clues. Examples of 

treasures recently unearthed are Darwin's Geological 

Specimen Notebooks, conveyed in 1981 from the Miner- 

alogy and Petrology Museum to the University Library 

by Dr. Sandra Herbert, my finding of his Plant Notes 

in the Cambridge University Herbarium, and my recent 

discovery that the notes on Insects in Spirits of 

Wine, thought to have been missing from the Insect 

Department of the British Museum (Natural History) 

since 1927, are right where they should be. Informa- 

tion from these sources and others will be used in 

discussing where the specimens are now to be found 

and how they arrived there, with emphasis on the 

plants and fungi. 


OLSON, JERRY S. Environmental Sciences 

Division, Oak Ridge National Laboratory, Oak 

Ridge, TN 37830.- Mapping World Vegetation 

for Ecosystem Cycling. 

Forest clearing, cutting, and fire have decreased 

areas and age classes of woody vegetation and 

lowered global pools of phytomass and its organic 

carbon, nitrogen, and sulfur compared with preagriculture 

or preindustrial times. A computer data 

base helped generate color separation plates for 

printing a map of 44 land ecosystem complexes in 

seven broad groups: FOREST AND WOODLAND; INTER- 

RUPTED WOODS; MAINLY CROPPED, RESIDENTIAL, COMMER- 

CIAL, PARK; GRASS AND SHRUB COMPLEXES; TUNDRA AND 

DESERT; MAJOR WETLANDS; and OTHER COASTAL, AQUATIC, 

AND MISCELLANEOUS. A global esti ate for C in 

live plants near 560 ? 100 Pg (10 tons) is far 

below estimates formerly used in some carbon 

cycling analyses. Tropical forests (1) probably 

already have been reduced more than is commonly 

realized, and (2) may never have been as widespread 

or massive as recently supposed. 

Research supported jointly by the Carbon 

Dioxide Research Division, U.S. Department of 

Energy, under contract W-7305-eng-26 with 

Union Carbide Corporation and the U.S. National - 

Science Foundation's Ecosystem Studies Program 

under Interagency Agreement No. DEB 77-26722. 

HISTORICAL SECTION 


Historical Section 65 

PRINGLE, JAMES S. Royal Botanical Gardens, Box 

399, Hamilton, Ontario, Canada L8N 3H8. 

- Biographical notes on two collectors cited in 

Hooker's Flora Boreali-Americana. 

Anne Mary Perceval (1790-1876) was the daughter of 

Sir Charles Flower, Bt., Lord Mayor of London. She 

came to Quebec in 1810 when her husband was 

appointed H.M. Collector of Customs. The Percevals 

acquired a large estate with extensive woodlands in 

nearby Sillery, part of which is now the Bois de 

Coulonge. Mrs. Perceval, along with William and 

Harriet Sheppard, was probably recruited as a 

collector for Hooker's Flora by the Countess of 

Dalhousie. Her collecting sites included Sillery, 

Ste.-Foy, and Cap Rouge; recipients of specimens, 

besides Hooker, included Darlington, Torrey, and 

Schweinitz. She returned to Britain in 1829, and 

spent her latter years on the Isle of Lewis. 

Clement Charles Todd (d. 1828), a naval surgeon, 

served at Kingston and in the Battle of Lake 

Champlain before being sent to Penetanguishene in 

1819. He was already knowledgeable in botany when 

he was invited to collect plants for Hooker by John 

Richardson in 1825, when the 2nd Franklin Expedition 

passed through Penetanguishene. Todd collected on 

the Penetanguishene Peninsula and along the Severn 

River from 1825 through 1827. His paper on the 

climate of Penetanguishene includes the first 

publication of phenological observations in Upper 

Canada. He returned to London for further study in 

1827, and died there while awaiting duty on H.W. 

Bayfield's Gulnare expedition. 

RUDOLPH, EMANUEL 

D. Department of Botany, The 

Ohio State University, Columbus, OH 43210. - The 

role of Almira Hart Lincoln Phelps in the spread 

of botany in nineteenth century America. 

Mrs.Phelps as a young woman came under the influence 

of her older sister Emma Willard, who helped form her 

educational philosophy, and of Amos Eaton, who helped 

form her botanical and scientific understanding. 

Feeling the lack of a suitable botanical textbook to 

introduce students to the subject, particularly fe- 

male students who were becoming more prevelant, she 

wrote one, Familiar Lectures on Botany, published in 

1829, using her first husband's sirname. Mrs. 

Lincoln's Botany quickly became popular and continued 

to be revised and reprinted through 1875. In 1833, a 

second botany text for lower level students, Botany 

for Beginners, appeared. It too, went through many 

reprintings up to 1870. Mrs. Phelps' other books and 

writings on science and education were popular also. 

The botanical texts were educationally innovative in 

starting with flower structure using common living 

examples and later considering other morphological 

and physiological aspects of plants. The Linnean 

System was used to classify the "most common native 

and foreign" plants that were described. Clear 

figures, often copied from well-known authorities 

helped to instruct teachers and students. Because of 

its wide useage, even in later years in competition 

with the textbooks of Asa Gray and Alphonso Wood, 

Mrs. Phelps' books were an important factor in 

educating many students, especially females, in 

botany and inducing some of them to have a life-long 

interest in the science.

66 Microbiological Section 


MICROBIOLOGICAL SECTION 

TRAQUAIR, JAMES A.*, and RENEE B. MELOCHE. 

Research Station, Agriculture Canada, Harrow, 

Ontario, Canada NOR 1GO; SHANNON M. BERCH. 

Departement d' Ecologie-Pedologie, Universite 

Laval, Ste-Foy, Quebec, Canada GlK 7P4. - 

Endotrophic (vesicular-arbuscular) mycorrhizae 

of Prunus persica. 

Three seedling rootstocks of peach (cv. Bailey, Harrow 

Blood, and Siberian-C) were compared with respect to 

endomycorrhizal colonization. The incidence of arbuscules 

and vesicles was noted in feeder roots fixed 

in formalin-acetic acid-alcohol (FAA) and stained 

with acid fuchsin. Spore frequency in nursery soil 

associated with these roots was determined by flotation 

and wet-sieving techniques. Microscopic examination 

of stained root segments revealed extensive 

colonization of the cortex by endotrophic mycorrhizal 

fungi. External mycelium, lobulate infection hyphae, 

arbuscules in various stages of development, and 

vesicles were evident in all three hosts. Arbuscules 

were observed more frequently in Bailey or Harrow 

Blood roots than in Siberian-C (p = 0.05) but arbuscular 

frequencies in Bailey or Harrow Blood did not 

differ. No differences were observed between the 

cultivars with respect to intensity of endomycorrhizal 

colonization, fungal types or the number of soilborne 

spores. Spore densities were high (in the 

order of 30-60 spores/g soil) but many of these propagules 

were apparently inviable. Glomus and Gigaspora 

spp. were distinguished on the basis of spore 

size and morphology. 


CAVENDER, JAMES C. Department of Botany, Ohio 

University, Athens, Ohio 45701 - Cellular Slime 

Molds of the Rocky Mountains. 

Soil populations of cellular slime molds are generally 

smaller and less diverse in soils of Rocky 

Mountain forests than in eastern deciduous forests. 

CSM were found at all elevations and habitats sampled. 

Of these, which exist along an altitudinal 

gradient-desert scrub, pinyon-juniper, ponderosa 

pine, spruce-fir and tundra, the subalpine spruce-fir 

belt, the most humid of the forest belts in this 

relatively dry region, proved to have the largest and 

most diverse populations. Almost all sites were 

dominated by two species Dictyostelium mucoroides and 

D. sphaerocephalum. Since Rocky Mountain soils are 

exposed to severe environmental fluctuations these 

two species are the most tolerant of the dictyostelids, 

particularly to moisture and temperature 

conditions. Dictyostelium septentrionalis was the 

only rare species discovered. 

GRENVILLE, D.J. and Y. PICHE. Department of 

Botany and Genetics, University of Guelph, Guelph, 

Ontario, Canada NlG 2W1 

- Sclerotial development in two ectomycorrhizal 

fungi, Pisolithus tinctorius (Pers.) Coker & 

Couch. and Paxillus involutus (Batsch) Fr. 

The sclerotia of Pisolithus tinctorius form in an 

intercalary position on mycelial strands following 

ectomycorrhizal formation. Initiation involves 

numerous outgrowths of hyphal tips that branch 

frequently to form a tightly knit, lenticular 

swelling. Initiation of sclerotia occurs on 

mycelial strands that have turned bright yellow. 

Sclerotia are also yellow until they form a hard, 

black, smooth rind at maturity. SEM studies show 

that the developing sclerotia consist of interwoven, 

highly branched mycelia with the external hyphae 

possessing clamp connections and an extracellular 

coating. TEM studies show a fibrillar substance 

between the thick walled outer hyphae which possess 

dolipore septi. Light microscope studies and pre- 

liminary histochemical investigations indicate that 

the sclerotia have an outer rind of thick-walled 

hyphae surrounding a medulla where lipid, phenolic 

compounds and other storage substances are found. 

Sclerotial development in Paxillus involutus is 

similar to that of P. tinctorius; however, formation 

is more rapid. Sclerotia of P. involutus are 

spherical rather than lenticular and develop from 

buff brown mycelial strands and remain this colour 

until a black rind is formed at maturity. Sclerotia 

of P. involutus will also form on culture plates. 

Sclerotia of both fungal species are readily 

produced in growth pouches in association with Pinus 

strobus. It is possible that the sclerotia of these 

two species can be used as germplasm sources for 

further study of mycorrhizal systems and perhaps for 

inoculation of nursery stock. Research supported by 

a NSERC grant to R.L. Peterson. 

SINHA, ASHA. Department of Mycology and 

Plant pathology, Institute of Agricultural 

Sciences, Banaras Hindu University, 

Varanasi - 221005, India. 

- Microbial population of litter in a 

tropical deciduous forest. 

Microbial decomposition of litter, collected 

from natural forest of Varanasi, was carried 

out by nylon bag technique. Fungal, bacter- 

ial, and actinomycetous populations were in- 

vestigated monthly. The fungi were grouped 

as "dominant", "common"f, "frequent", and 

"rare" depending on their percentage 

frequency, abundance, sporulation and time 

of appearance in different months. Alter- 

naria alternata, Aspergillus flavus, 

A. niger, Cladosporium herbarum, Discosia 

maculicila, Fusarium semitectum, Phoma 

hibernica, Penicillium citrinum, P. rubrum, 

Torula graminis, Trichoderma harzianum and 

Dark sterile mycelium are recorded as domi- 

nant fungi. Arthrobacter, Bacillus, Pseu- 

domonas and Micrococcus were found to be 

dominant bacteria. The maximum fungi 

(86.25 x 104/g), actinomycete5 (38.75 x 106 

/g), and bacteria (16.87 x 10 /g) were 

recorded in August and minimum fungi (29.5 

x 104/g) in February, actinomycetes (11.36 

x 106/g) in May and bacteria (31.63 x 107/g) 

in March. Monthly variation in microbial 

population correlated with some climatic 

factors like moisture content, temperature, 

and relative humidity. 

WILL III, OSCAR H., MANFRED RUDDAT AND EDWARD D. 

GARBER. Department of Biology, Barnes Laboratory, 

University of Chicago, Chicago, IL 60637 

-Carotenes and cytochrome c in Ustilago violacea 

Pigmentation in the smut fungus, U. violacea, results 

from the accumulation of carotenes and/or cytochrome

c. HPLC and spectroscopy were used to characterize 

and quantify the carotenes in white, pink, yellow, 

orange and pumpkin strains of U. violacea and liquid 

N2 spectroscopy of whole cells or alkali extracts 

were used to quantify the cytochrome c levels. White 

strains contained only phytoene and/or traces of ly- 

copene, 13-zeacarotene, y-carotene, or 13-carotene and 

0.15 x 10-11 mg/cell of cytochrome c. Pink strains 

contained either no carotene or a mixture of colored 

carotenes (30-60 x 10-12 mg/cell). The cytochrome c 

content of pink strains was about 14 times that of 

white strains. The yellow strain accumulated a mix- 

ture of colored carotenes at a level of 10 x 10-l 


ASH, SIDNEY. Department of Geology-Geography, 

Weber State College, Ogden, Utah 84408. - Contras- 

ting floras of the Upper Triassic bentonitic and 

redbed lithogenetic sequences of the Colorado 

Plateau. 

The Upper Triassic continental rocks of the Colorado 

Plateau region have been subdivided by Stewart (1969) 

into three lithogenetic sequences that reflect the 

origin of the strata. Distinctive and contrasting 

floras which also seem to reflect the origin the 

strata occur in the two lower sequences. The lower- 

most sequence, the bentonitic sequence, consists 

principally of variegated bentonitic claystone, clay- 

ey sandstone, and conglomerate. It is thought to 

have been deposited primarily in streams and lakes 

and on floodplains. Plant fossils are common in the 

bentonitic sequence and most of those which have been 

described from the Upper Triassic rocks in the 

Colorado Plateau occurred at many places in this 

sequence. Nearly 60 species have been described from 

the sequence including representatives of most major 

plant groups. The fossils are generally fragmentary 

and most have been transported prior to burial and 

fossilization. The leaves are usually preserved as 

compressions. The overlying sequence, the redbed 

sequence, consists mostly of reddish-brown or reddish 

-orange siltone. It is thought to have been deposit- 

ed in lakes and on floodplains. In contrast to the 

situation in the bentonitic sequence, plant fossils 

are rare in the redbed sequence. They are known from 

only four areas and only four identifiable species 

have been described from the sequence. Most of the 

fossils have not been transported and occur in the 

position of growth. These include Neocalamites sp., 

Peloudea poleonensis, and Sanmiguelia lewisii. 

Typically, the fossils are preserved as impressions 

and pithcasts. 

BASINGER, JAMES F. and DAVID L. DILCHER. Dept. of 

Geological Sciences, University of Saskatchewan, 

Saskatoon, Saskatchewan S7N OWO, and Dept. of 

Biology, Indiana University, Bloomington, IN 47405. 

-Fruits of Cercidiphyllum from the early Tertiary 

of Ellesmere Island, arctic Canada. 

Numerous clusters of follicles have been recovered 

from Paleocene shales of the lower Eureka Sound 

PALEOBOTANICAL SECTION 

Paleobotanical Section 67 

mg/cell and cytochrome c at a level similar to that 

of the white strains. The pumpkin and orange strains 

accumulated carotenes at a level intermediate to pink 

and yellow strains. The cytochrome c content in the 

orange and pumpkin strains was similar to the pink 

strains. The white phenotype results from a general 

lack of colored carotenes and a physiological level 

of cytochrome c, while the pink phenotype results 

primarily from cytochrome c and in some pink strains 

also from colored carotenes. The pumpkin and orange 

phenotypes result from the presence of high cytochrome 

c levels and colored carotenes and the yellow pheno- 

type from low cytochrome c and colored carotenes. 

Formation, Fosheim Peninsula, Ellesmere Island, 

79?47'N 85?6'W. Individual follicles are about 13 mm 

long and 2 mm wide, are sickle-shaped, and are 

arranged so that tips converge at-the tops of the 

clusters. Clusters are globose, 15-20 mm in 

diameter, with a peduncle about 10 mm long. The 

peduncle branches a few times at the base of the 

cluster to produce about 15 follicles borne in a 

terminal position. Fruits had dehisced prior to 

fossilization; seeds have not been found. Dehiscence 

occurs on both ventral (toward center of cluster) and 

dorsal surfaces. The fruits are associated with a 

low diversity flora including leaves of 

Cercidiphyllum, Tilia?, Glyptostrobus, and 

Metasequoia. While these compact clusters of fruits 

resemble reproductive organs of late Tertiary, and to 

some degree modern, Cercidiphyllum, they are unlike 

the elongate, multifollicular axes typically 

attributed to early Tertiary (Paleocene) 

Cercidiphyllum. This fossil material from Ellesmere 

Island may represent a lineage more closely allied to 

the living species than the Cercidiphyllum recognized 

in more southerly, early Tertiary localities. It is 

particularly interesting that these compact fertile 

shoots are found at an earlier age in the high arctic 

area than at lower latitudes. 

BEELER, HAZEL E.* and STEPHEN E. SCHECKLER. 

De- 

partment of Biology, VPI&SU, Blacksburg, VA 24061. 

-A new Upper Devonian tree lycopod. 

A new tree lycopod has been discovered in the upper 

Hampshire Formation (mid to late Famennian) exposed 

at Elkins and Valley Head, WV, and Rawley Springs, 

VA. Axis fragments range from 3mm-6cm in diameter, 

and the largest do not appear to have been at the 

base of the plant. Taper of axes suggests the plant 

was 3-6m tall. Forking is equal and mainly in the 

crown. Outer surface of axes is smooth, without leaf 

cushions, but with vertically elongated, elliptical, 

slightly raised leaf scars, which are sparsely spaced 

and in a steep spiral. The exarch xylem cylinder is 

smooth and lacks pith in mid-sized axes. As in most 

lycopods, the stele occupies only a small portion of 

the stem (ca. 2mm in a 14mm diameter axis). The outer 

configuration of the new lycopod resembles Helenia 

and Heleniella, which are probably decortications, 

and some decorticated Lepidodendropsis. The latter, 

however, bears its leaves in a different arrangement 

from the new lycopod and has a ridged xylem cylinder. 

Furthermore, presence of epidermis, cuticle and 

leaves on some axes of the new lycopod indicate that 

we have its true outer surface. The new lycopod

68 Paleobotanical Section 

appears to have been restricted to a near-swamp com- 

munity. It is rare or absent both in floodplain sheet 

deposits and Rhacophyton swamps. When present in the 

latter, it seems to have been transported only a 

short distance, and becomes more common in the coars- 

ening-upward sequences produced by swamp filling. The 

plant also occurs in allochthonous shoreline storm 

deposits near Rhacophyton swamps. This new tree 

lycopod is significant because it occurs in the near- 

swamp environment rather than being dominant in the 

swamp community as Lower Carboniferous tree lycopods 

are. 

BLACKWELL, WILL H., * WAYNE D. MARTIN1 and ROBERT G. 

McWILLIAMS.2 Department of Botany and 152Department 

of Geology, Miami University, Oxford, OH 45056. 

- Algal Remains in Cryptalgal Laminated Carbonates 

of the Upper Middle Cambrian of Northwest Wyoming. 

Cryptalgal laminites, regarded by some as a type of 

stromatolite, form areally extensive beds cropping 

out sporadically in the Rocky Mountains from northwest 

Wyoming to northwest Canada. At Torrey Canyon, 

in the northwestern part of the Wind River Basin of 

Wyoming, rock specimens of planar, algal laminated 

lithofacies were collected immediately below an edgewise, 

lime pebble conglomerate in the upper part of 

the Park Shale Member of the Gros Ventre Formation, 

Upper Middle Cambrian. Thin sections of these 

micrites reveal preserved organic remains including: 

a dominant, filamentous, prokaryotic mat-former; 

other probable prokaryotes; 

eukaryotic algal filaments. 

and larger, 

The algal 

possibly 

composition is 

not unlike that reported for silicified, Late Precambrian 

Conophyton from the Soviet Union. Conophyton 

is locally common in the Cambrian and Ordovician of 

northwestern Wyoming. Regional stratigraphic considerations 

suggest that widespread occurrence of stromatolites 

and algal mats was due primarily to changes 

in sea level. Our studies and observations indicate 

that: 1) identifiable algal 

2) stromatolitic associations 

remains may be present; 

such as Conophyton and 

cryptalgal laminites were prevalent in the early 

Phanerozoic; 3) the disappearance and reappearance of 

stromatolitic forms was due at least as much to sedimentary 

and eustatic change as to metazoan grazing 

pressure or competition; and 4) the smooth, flat, 

millimeter-thick sediment laminations occurring in 

Holocene tropical carbonate flats, as for example on 

northwest Andros Island, Bahamas, are precise modern 

analogs 

laminites. 

of the Upper Middle Cambrian cryptalgal 

BRACK-HANES, SHEILA D.*, MICHELLE J. 

BALLARD, and THOMAS R. LANE. Natural 

Sciences, Eckerd College, St. Petersburg, 

FL 33733. - Lycopod reproductive struc- 

tures from the Late Mississippian of 

Georgia. 

Mississippian (Chesterian) lycopod compres- 

sions from northwestern Georgia include cone 

fragments of Lepidostrobus, Lepidostrobo- 

phyllum, and isolated EchitrIletes echinoi- 

esimeaspores. Lycospora microspores of 

the cone have a broad eqitorial flange and 

a punctate proximal surface. Echitriletes 

echinoides, which is abundant in the shale, 

is alsothie spore type found in the sporan- 

gia of the Lep idostrobophyllum compressions. 

Previously, the spiny megaspores have been 

reported from sporangia of a different 

sporophyll, Lepidostrobophyllum fimbriatum. 

The Georgia Lepidostrobophyllum is smaller 

with a distinctively narrow lamina that has 

entire margins. 

BRACK-HANES, SHEILA D.* and ALICE PERUS- 

SAULT. Natural Sciences, Eckerd College, 

St. Petersburg, FL 33733. - A seagrass 

compression from the Middle Eocene of 

Florida. 

The Avon Park Limestone (Claiborne) contains 

a marine flora with several distinctive sea- 

grasses. Most prominent among them is one 

that closely resembles Thalassia (turtle 

grass of the Hydrocharitaceae family) in its 

morphology. There are certain fqatures, how- 

ever, such as a dark dorsal band on its 

leaves in the region of its sheath, that is 

characteristic of another seagrass, Posidonia 

(Potamogetonaceae family). The dark band in 

Posidonia represents a heavy deposit of 

tannin cells in the leaf-sheath area where 

the leaf is contiguous with its sheath. In 

Posidonia, a ventral ligula with numerous 

tannin cells, also occurs in the region of 

the dark band. The Avon Park seagrass is 

believed to be a ligulate plant of the 

Potamogetonaceae family that, until now, has 

been unknown in Eocene rocks. 

BURNHAM, ROBYN J. Department of Botany KB-15, 

University of Washington, Seattle, WA 98195. 

-Diversification and stable distribution with 

respect to temperature in early Tertiary Ulmoideae 

of western North America 

Appearance and major morphological diversification of 

each of three genera of the Ulmoideae (Ulmaceae), 

Ulmus, Zelkova, and Chaetoptelea, follow the same 

pattern during the early Tertiary of western North 

America. Each genus is represented by a homogeneous 

morphospecies first occurring in the Paleocene or 

early Eocene, 

diversification. 

followed by a middle to late Eocene 

The diversifications produce distinctive 

new morphological species within the same 

basic organizational plan recognized today for each 

genus. The initial appearance of new forms occurs 

during or immediately following periods of inferred 

climatic 

equable 

instability 

conditions. 

in floras indicating less 

Superimposed on the patterns of 

diversification are indications of consistent distribution 

with respect to temperature of each genus 

throughout the early Tertiary that are comparable 

the climatic ranges of the genera today. Species 

to 


each genus, as a group, contribute to specific 

physiognomic forest types and to floral assemblages 

that suggest specific temperature parameters. Species 

of Ulmus and Zelkova delimit the widest temperature 

and geographi.c ranges of the subfamily, occupying 

modern habitats in notophyllous broadleaved evergreen 

forests through low montane conifer forests of Asia. 

The same ranges are indicated by occurrences in early 

Tertiary floras. The monotypic Chaetoptelea is 

restricted today to paratropical and notophyllous 

broadleaved forests of Central America and apparently 

has been restricted to these physiognomic forest 

types since the Paleocene. 

CHITALEY, SHYA. The Cleveland Museum of Natural 

Hi story, Cl evel and, OH 44106 

- Cones from the Cleveland Shale. 

Two well preserved compressed Lycopsid cones are de- 

scribed in this paper. Both are from the dig of the

I-71 Interstate passing through Cleveland of Ohio at 

the intersection of I-71 and West 130th Street, ex- 

posing the Black Cleveland Shale. They are studied 

under low and high magnifications for their mor- 

phology and structure after clearing and macerating 

with hydrofluoric acid. 

The Cone A is elongated, exposed in part and 

counterpart, showing a central axis with whorls of 

sporophyll/sporangium complexes. It measures 11.7 

X 4.5 cm; axis 0.6-1 cm wide and the strap shaped 

sporophyll/sporangium complex 1.7 X 0.3 cm. 

The Cone B is ovate showing a portion of central 

axis in the middle and at either ends sporophyll/ 

sporangium complexes arranged in a shallow helix 

around the axis. It measures 13 X 5.3 cm; axis 

1 cm; sporophyll/sporangium complex 1.2 XO.2 cm. 

Miospores are of two sizes in both A and B. The 

cones are compared with the known ones for their 

affinities. Cone A shows greater resemblance to 

Lepidostrobus gallowyi than the B. The presence of 

such big arborescent cones in the Upper Devonian 

Cleveland Shale is of high significance. 

CICHAN, MICHAEL A. Department of Botany, 

The Ohio State University, Columbus, OH 

43210. - The vascular cambium in 

Carboniferous plants: Arthropitys communis. 

Developmental patterns in the vascular cambium 

of Arthropitys communis, a Carboniferous 

arthrophyte, are characterized through an 

analysis of structural changes that occur 

in the secondary xylem. By examining cell 

lineages in tangential sections and using an 

equation that predicts the minimum rate at 

which new initials are added to the cambium, it 

is shown that circumferential enlargement of 

the layer occurred by an unusual mechanism 

involving both cell division and enlargement. 

Ray initials were added to the cambium at a 

relatively high rate by the division of 

existing ray initials. New fusiform initials 

were formed at relatively low rates, and 

preliminary evidence suggests that the process 

was accomplished, at least in part, by the 

conversion of ray initials to fusiform 

initials. With respect to cell size, there is 

a gradual centrifugal increase in the length 

and tangential diameter of the fusiform cambial 

elements. A similar developmental increase is 

observed in the tangential size of ray 

initials. A general comparison of the pattern 

observed in A. communis with that found in 

other Carboniferous arthrophytes, while 

illustrating the distinctive nature of the 

cambium in this group, docuiarets the occurrence 

of diverse developmental regimes in these 

evolutionarily primitive plants. 

CICHAN, MICHAEL At and THOMAS N. TAYLOR. 

Department of Botany, The Ohio State 

University, Columbus, OH 43210. - An alternate 

method for determining tracheid length in 

petrified wood. 

To date, studies of the anatomy of fossilized wood 

from vascular cryptogams and gymnosperms have 

generally neglected the length of the tracheary 

elements. This is due primarily to the fact that, 

unlike the wood of living plants, petrified wood 

is not amenable to maceration procedures. 

Moreover, the unusual length and often sinuous 

coulrse of the tracheids generally precludes direct 

measurement of the cells in longitudinal sections. 


In this paper, a frethod is presented which allows 

estimates of tracheid length to be made by 

analysis of intersected cells in cross section. 

Using a nodel which simulates the organization of 

tracheids in a hypothetical tangential section of 

wood, an equation is derived which relates cell 

length to the ratio between the number of 

intersected shafts and apices observed in cross 

section and the length of the tracheid apex. It 

is determined a priori that the accuracy of the 

length estimates obtained using this method will 

vary in accordance with the general features of 

the area of wood being analyzed and mrphological 

variability in the ccmponent tracheids. Use of 

the technique is demonstrated in an analysis of 

wood from the anatomically preserved Carboniferous 

arthrophyte Sphenophyllum plurifoliatum, a plant 

known to possess extremely long tracheids. The 

lengths obtained using this method correspond 

closely to those derived by indirect measurement, 

and it is concluded that the technique is a 

valuable tool in characterizing the length of 

cells which, for various reasons, can not be 

measured directly. 

COSTANZA, SUZANNE H. Department of Botany, 

University of Illinois, Urbana, Ill. 61801 

- Comparison of two Pennsylvanian 

cordaites. 

coal swamp 

Two distinct Euramerican Pennsylvanian coal swamp 

cordaite genera, Mesoxylon and Cordaixylon 

(previously Pennsylvanioxylon) differ in several 

ways. Mesoxylon primary xylem strands, radially 

narrow and tangentially broad, are indistinct. 

Cordaixylon primary xylem is clearly defined, with 

strong pithward projection and lateral edges. In 

woody Mesoxylon, the originally single leaf trace 

divides into two at the inner xylem margin, but in 

equivalent Cordaixylon leaf traces first divide in 

the cortex. Small branch traces, usually paired, 

fuse in the cortex in Mesoxylon but remain separate 

in Cordaixylon. Mesoxylon leaves are probably inserted 

in complex multiple spirals whereas Cordaixylon 

leaves follow a single spiral. Associations 

of ovules with other organs are strongly supported 

by repeated occurrences of single-ovule floras. The 

plant producing Mesoxylon stems most probably 

produced Gothania reproductive shoots, Mitrospermum 

ovules, and thick leaves such as Cordaites felicis 

with strong interveinal sclerenchymal bands. The 

Cordaixylon plant produced Cordaianthus reproductive 

shoots, Cardiocarpus ovules, and thinner leaves which 

may or may not have strong interveinal sclerenchyma. 

Because of small stem size, and adventitious roots 

and buds, coal swamp species in these two genera are 

reconstructed as small trees or viny shrubs. The 

small stems contrast with large trunks from other 

depositional settings, such as French Stephanian 

Grand'Croix freshwater swamps. The size difference 

between in-swamp and out-of-swamp, lowland plants is 

also seen in lycopods. Thus, although coal swamps 

were areas of accumulation, they may not have been 

optimal for individual plant growth. 

CRABTREE, DAVID R. Department of Botany, 

University of Montana, Missoula, MT 59812 

- A regional fern flora from the Albian (Cret- 

aceous) of Montana, Idaho and Wyoming. 

A Lower Cretaceous (late Albian) regional fern flora 

is reported from Montana, Wyoming and Idaho. Members 

of the Schizaeaceae, Gleicheniaceae, Cyatheaceae and 

Polypodiaceae are present. The assembl ages are found


in rocks interpreted as paludal. Several of the ferns 

exhibit distributions across North America and Europe. 

They apparently represent a portion of a Cretaceous 

fern assemblage that was widely sucessful in lowland 

and deltaic environments. Several of the ferns report- 

ed here have been inconsistently classified in pre- 

vious reports. Attempts are made to clarify the dist- 

ribution and taxonomy of Gleichenia graciliss, Anemia 

dicksonianum, Ruffordia goepperti, and Onychiopsis 

psilotoides. 

CRANE, PETER R. Department of Geology, Field 

Museum of Natural History, Lake Shore Drive, 

Chicago, IL 60605-2496 

- Heterophylly in Paleocene Lauraceae 

A suite of fossil leaves from the Reading Beds (Upper 

Paleocene) of southern England contain distinctive 

and abundant, spherical resin-bodies in the leaf 

mesophyll. The morphology and major venation of 

these leaves may be trilobed and palactinodromous, 

simple and pinnate, or simple and acrodromous. 

Simple and trilobed leaves yield identical cuticles, 

and are interpreted as variants from a single 

heterophyllous species. Impressions of similar 

fossil leaves have been reported from the Paleocene 

of northwest Greenland, and Menat, southern France. 

Characters of gross morphology and major venation 

indicate a relationship to the Lauraceae, which are 

known from fruit remains to comprise a major 

component of the British early Tertiary flora. Three 

extant species of Sassafras and one extant species of 

Lindera display heterophylly similar to that in the 

fossil leaves. The resin bodies in the fossil are 

interpreted as the remains of ethereal oil cells and 

the major cuticular characters are similar to those 

of many extant Lauraceae. However, details of the 

fossil cuticle show no close similarity with any 

living species and provide no evidence for confident 

assignment to either Lindera or Sassafras. The 

fossil leaves are referred to Lauraceaephyllum 

stenolobatus Koch. Details of morphology, 

particularly in the trilobed leaves, are also 

different from "mature" leaves of extant species and 

most closely resemble seedling leaves of Lindera 

triloba. Trilobed leaves more closely comparable 

in morphology to "mature" leaves of Lindera and 

Sassafras appear later in the fossil record. 

CREPET, W. L. * and MICHAEL S. ZAVADA. Biological 

Sciences Group U-42, University of Connecticut, 

Storrs, 

Indiana 

Ct. 06268 and Department of Biology, 

University, Bloomington, Ind. 47405 - 

Quercoid catkins from the Middle Eocene. 

Apparently lax catkins of small florets have been 

discovered from the Middle Eocene Claiborne Formatiom 

Floral morphology is suggestive of affinities with 

the subfamily Quercoideae of the Fagaceae. Pollen, a 

good diagnostic character at the subfamily level 

in the family, is tricolporate and is similar to 

the pollen of the Quercoideae in P/E ratio 

s ize . Ornamentation, al so a good diagnostic 

and in 

feature, 

is more typical of the subfamily Castaneoideae. 

These are the oldest unequivocally quercoid fossils 

and their significance is evaluated in the contexts 

of the subfamily, family, and fossil record. 

DAGHLIAN, CHARLES P. Department of Botany 

and Microbiology, University of Oklahoma, 

Norman, OK 73019 

-Epilobium pollen from the Oligocene of 

New Zealand. 

Pollen of Epilobium has been reported previ- 

ously from the Oligocene of New Zealand but 

was considered by earlier workers to be a 

Recent contaminant. New material from the 

Pomahaka Formation (Late Oligocene) of New 

Zealand provides evidence that Corsinipol- 

lenites epilobioides is not a contaminant. 

Combined LM, SEM and TEM observation of this 

palynomorph indicates it is a member of the 

Onagraceae on the basis of its characteristic 

wall structure. The fossil grains can be 

allied most closely with Epilobium on the 

basis of exine structure, particularly the 

ektexine-endexine relationship, exine sculp- 

ture, aperture configuration and gross form. 

This species of Epilobium in the Late Oligo- 

cene may or manot have given rise to the 46 

native species of the genus in Australasia, 

but suggests that some of these species may 

have had a much longer period of residence 

in the region than previously recognized. 

This new record is important in interpreting 

the history and biogeography of Epilobium 

and of the Onagraceae. 

DELEVORYAS, T.* and R. C. HOPE. Department of 

Botany, University of Texas, Austin, TX 78712 and 

Department of Geology, Campbell University, Buies 

Creek, NC 27506. - Further notes on the late 

Triassic conifers Compsostrobus neotericus and 

Voltzia andrewsii. 

In the original description, ovulate cones of Compso- 

strobus neotericus Delevoryas and Hope were reported 

to have ovuliferous scales with two ovules borne on 

the upper surface of each. Although most ovuliferous 

scales were preserved without attached ovules, two 

distinct scars are present on each, suggesting a pair 

of ovules. On the basis of a single ovuliferous 

scale with attached ovules, the reconstruction showed 

the two flattened ovules borne on edge, with flat 

faces parallel to each other. Additional material 

confirms the presence of two ovules per scale, but 

the ovules appear to have been borne with flat faces 

resting on the ovuliferous scale. The coeval cone of 

Voltzia andrewsii Delevoryas and Hope had lobed ovuli- 

ferous scales, but no subtending bracts had ever been 

detected. It is now demonstrated that a small, 

tapered bract subtended each scale. Immature cones 

of V. andrewsii also contribute information about 

cone ontogeny. 

DIMICHELE, WILLIAM A. Botany Department, Univ. 

of Washington, Seattle, WA 98195 

Timing and controls of diversification in the 

Carboniferous Lepidodendrales 

Phylogenetic analysis of the Lepidodendrales, sub- 

sequently combined with stratigraphic data provide 

the basis for explaining the timing of generic diver- 

sification and the relative species diversity of each 

genus. The following patterns are observed: 1. Para- 

lycopodites is both the oldest and has the fewest 

derived, character states of the group. It occurs

initially in a diversity of ecological settings, later 

is ecologically narrow, consists of few species, and 

possibly includes species ancestral to three other 

genera in the Mississippian. 2. The only major adap- 

tive radiation occurred in the Mississippian, shortly 

after the appearance of Paralycopodites. 3. Three of 

the subsequently appearing genera, Sigillaria, true 

Lepidodendron, and "Lepidodendron" (sensu L. vascu- 

lare), consist of numerous species that occur in 

relatively heterogeneous ecological settings, and 

contain the probable ancestors of some taxa above the 

species level. 4. Lepidophloios consists of few 

species with narrow ecological tolerances, and was 

apparently ancestral to no superspecific taxa. These 

patterns suggest that the major delimiters of the 

generic adaptive radiation were increased morphologi- 

cal and ecological specialization of the newly 

appearing forms, preempting 'adaptive space'. 

Increased architectural complexity may also be impor- 

tant in the limiting the magnitude of actual and 

detectable morphological divergence in speciation. 

FARABEE, MICHAEL J.* Department of Botany & Microbiology, 

University of Oklahoma, Norman, OK 73019. 

JAMES E. CANRIGHT Department of Botany & Microbiology, 

Arizona State University, Tempe, AZ 85287. 

- A new genus of dispersed fossil pollen from the 

Upper Cretaceous of North America. 

A new genus of dispersed fossil pollen is described 

from Maestrichtian deposits in the Aquilapollenites 

and Normapolles phytogeoprovinces in North America. 

These deposits had lithologies ranging from shale to 

lignite, were widely separated geographically, and 

had characteristic Maestrichtian palynofloras. The 

genus occurs in the Lance Formation of Wyoming, the 

Owl Creek Formation of Kentucky, the Prairie Bluff 

Chalk Member of the Selma Group in Alabama, and an 

unnamed lignite from Arkansas. The genus is characterized 

by its subspherical amb, predominantly polar 

compression, hexaporotricolpate apertures, and an 

extexine composed of baculate sculpture elements 

forming a coarse reticulum (lumen sizes up to 2 

micrometers) with lumen sizes decreasing toward the 

colpi margins. The combination of these characters 

distinguish this new genus from previously described 

dispersed pollen genera. The same species occurs 

all four deposits, and thus is a useful tool for 

in 

correlating deposits between the distinct phytogeoprovinces. 

The precise botanical affinity of the 

genus is most likely with some extinct group of the 

Santalales, 

Olacaceae. 

possibly with precursors to some of the 

GENSEL, PATRICIA G. Biology Department, University 

of North Carolina, Chapel Hill, NC 27514 - 

A new, anatomically 

Devonian of Gaspe. 

complex plant from the Early 

Compressions, impressions and permineralizations 

were found of an apparently new plant from the Early 

EmBian Battery Point Formation, Gaspe, Quebec which 

most closely resembles the trimerophytes in vegetative 

morphology but exhibits anatomy more comparable 

to Middle Devonian plants such as Aneurophytales or 

Iridopteridales (sensu Stein, 1982). Major axes are 

0.7-1.0 cm wide and divide isotomously at least 

twice in a 15 cm distance. Each resultant axis may 

also divide anisotomously to produce spirally 

arranged lateral branches. These in turn divide 

one to several times, ending in recurved tips. All 

axes are covered with delicate hairs 0.3-0.6 tmm long. 


Regions of a*es on compressions are permineralized 

with pyrite and limonite; other permineralized axes 

occurred in nodules. Anatomy of main axes consists 

of primary xylem in the form of a deeply three-lobed 

protostele; one protoxylem area occurs near the end 

of each lobe and in the center. Maturation is 

mesarch. Elliptical lateral traces are produced by 

1) tangential enlargement of a lobe tip, first to 

one side and then the other; 2) enlargement of proto- 

xylem, and 3) separation of outer part of protoxylem 

and associated metaxylem. 

While superficially similar to certain Middle 

Devonian Aneurophytales, the new plant differs in 

lacking secondary xylem, having fewer protoxylem 

areas, and a different mode of lateral trace forma- 

tion. It differs from Iridopteridales in similar 

features. However, it demonstrates a much greater 

level of histological complexity than has been known 

to date among Early Devonian plants, and might 

represent a precursor to some of the above Middle 

Devonian forms. 

GRAHA.J,ALAN. Department of Biological Sciences, 

Kent State University, Kent, Ohio 44242- Miocene 

Communities from Costa Rica. 

A hallmark of tropical biotas is their diversity. The 

refuge theory of Haffer explains this diversity by 

assuming past climatic changes that periodically res- 

tricted the rain forest to isolated refugia, followed 

by sea-level and climatic changes that allowed these 

elements to expand and coalesce into the vegetation 

presently occupying the Amazon Basin. Since paleo- 

botanical data is not presently available directly 

from the basin, the theory depends on information 

from adjacent regions. van der Hammen has docuimented 

climatic and vegetation changes from high altitude 

lakes in Columbia, and data from the uppermost Miocene 

Paraje Solo formation in Veracruz, Mexico showed that 

in one region were rain forest exists today, it was 

absent or poorly represented in the past. New sup- 

porting data from Miocene microfloras in Costa Rica 

reveal a temperate community of Podocarpus and 

Quercus, presently found at higher altitudes in the 

Talamanca Range, while elements of the rain forest 

are absent or poorly represented. These results are 

consistent with those previously reported from Vera- 

cruz and Colombia. Until data directly from the 

basin, as at Rondonia, are more complete and better 

dated, the widely accepted refuge theory continues 

to depend on information from these peripheral regions 

for evaluation. 

GROTE, PAUL J.* and DAVID L. DILCHER. Department 

of Biology, Indiana University, Bloomington, IN 

47405. -Investigations of angiosperms from the 

Eocene of North America: A five carpellate fruit. 

Angiosperm fruits from the middle Eocene Claiborne 

Formation of western Kentucky and Tennessee have 

been studied. About 170 fruits of one similar type 

from several clay pits have been examined 

morphologically. The fruits consist of 5 fused, 

superior carpels and are terminal on short, frag- 

mentary woody axes. These fruits are compressed, 

mostly laterally, and are 10 to 23 mm. wide by 9 to 

18 mm. high. They are surrounded by 5 woody, im- 

bricate sepals. The sepals cover the fruit almost 

entirely when immature and about 1/3 when mature. 

Immediately subtending the sepals are 2-4 helically 

arranged bract scars. The fruits are woody, divided 

into 5 distinct locules, and dehisce loculicidally,


rarely breaking free to expose a central column. 

Each carpel contains one apparently anatropous seed. 

The seeds are pyriform (6x8 mm.) and are borne on 

axile placentae. The surface of each seed is papil- 

late. The carpels have a thin outer covering which, 

when preserved, is brittle and frequently broken 

away to expose a woody mesocarp with a reticulate 

surface. An endocarp can be differentiated toward 

the inner surface of the mesocarp surrounding each 

seed. These fruits appear to have an affinity with 

the Theaceae. 

HAMER, JON J. Department of Botany, Ohio 

University, Athens, Ohio 45701 - A permineralized 

sporangial fructification from the Upper 

Pennsylvanian of the Appalachian Basin. 

Several specimens of a new type of sporangial fructi- 

fication have been discovered in coal balls from the 

Duquesne Coal near Steubenville, Ohio. In the lar- 

gest specimen sporangia are borne terminally on up to 

two orders of branching axes. Penultimate axes 

branch pinnately to produce irregularly-branched ul- 

timate axes. Sporangial wall cells are of a single 

type and show no specialization for dehiscence. 

Spores are radial and trilete, and most similar to 

the sporae dispersae genus Dictyotriletes. The 

specimens are compared to Sclerocelyphus Mamay and to 

other Paleozoic fructifications of uncertain affini- 

ties. 

JOHNSON, NORMA G.*, ALFRED TRAVERSE and PAUL K. 

STROTHER. Department of Biology, Pennsylvania 

State University, University Park, PA 16802 and 

Department of Geology, Dickinson College, Carlisle, 

PA 17013 - Plant microfossils from the Lower Silurian 

Tuscarora Formation at Mill Hall, Pennsylvania, 

A 200 meter thick section of the Lower Silurian Tuscarora 

Formation near Mill Hall, Pennsylvania, yields 

palynomorphs such as Tetrahedraletes and Nodospora, 

as well as dyads and probable diacrodioid and sphaeromorph 

acritarchs. A series of time-lapse photographs 

shows significant changes in the spore morphology 

of Nodospora spp. during oxidation with chlorine 

bleach, apparently indicating that species of Nodospora 

previously thought to be distinct are based on 

natural or laboratory-induced differences in level 

of oxidation. Large (3/4 mm) pear-shaped spore clusters 

occur as megascopic fragments on shale surfaces. 

Studies using light and scanning electron microscopy 

show that these large spore clusters are composed 

uniformly of Tetrahedraletes medinensis. These plant 

microfossils were presumably deposited in a nearshore 

or fluvial environment. No forms known to be 

marine have been found in the Mill Hall samples, and 

the flora compares favorably with an undisputedly 

non-marine section of the Tuscarora Formation from 

Waggoners Gap, Pennsylvania. 

KASPER, JR.*, AiDREW E. AND WILLIAM H. 

FORBES. Department of Botany, Rutgers 

University, Newark, N.J. 07102 and Division 

of Mathematics and Science, University 

of Maine, Presque Isle, Me. 04769. 

- An early occurrence of P4-LfophypCon from 

the Upper Silurian/Lower Devonian Fish 

River _Lake Formation in northern Maine. 

Plant remains assignable to Psilophyton from 

the Fish River Lake Formation in northern 

M4aine may represent one of the earliest 

occurrences of the genus to date. The Fish 

River Lake Formation was named and described 

by Boone in 1970. It contains the unusual 

association of a continental flora with a 

marine fauna. The age determination based 

on several faunal collections is late 

Silurian to early Devonian--the upper limit 

being New Scotland, i.e., Helderberg 

(=Gedinnian/Siegenian) age. 'Three different 

localities have yielded compression speci- 

mens of axes bearing clusters of sporangia. 

Plants from one locality have unornamented 

and vertically ribbed stems up to 3 mm wide. 

They branch pseudomonopodially and the 

laterals undergo several dichotomies ending 

in recurved branchlets bearing clusters of 

sporangia. The sporangia are pendent, 

narrowly elliptical, paired and 3-5 mm long. 

Plants from another site likewise have un- 

ornamented and ribbed axes but are much 

smaller--l.5-2 mm wide. Branching is pseudo- 

monopodial and the ultimate branchlets bear 

minute paired sporangia 2-2.5 mm long. The 

former species is compared to Dawsonites 

arcuatus, the latter to Psilophyton dapsile. 

Most well-documented occurrences ot 

Psilophyton are Emsian to Eifelian in age. 

* 

KOVACH, WARREN L., & DAVID L. DILCHER. 

Indiana University, Bloomington, Ind., 47405. - A 

new mid-Cretaceous angiosperm fruiting axis. 

A new type of angiosperm reproductive axis has been 

found in the mid-Cretaceous sediments of the Dakota 

Formation in west-central Kansas, thus adding to the 

diversity of angiosperm reproductive structures known 

from this time. The largest axis fragment we have is 

15 cm long; the entire axis may have been longer. 

These reproductive axes are racemes which bear 

numerous helically arranged fruiting structures (4-5 

per cm). In some specimens, many of these fruiting 

structures have been shed and only the scars remain. 

Each of these fruiting structures consists of a 

pedicel (4 x 0.5 mm) which arches distally from the 

main axis, terminating in a spherical receptacle (1 

mm diameter) upon which are borne approximately 35-50 

small, helically arranged carpels. Each carpel is 

approximately 2 mm by 0.7 mm and is borne on a 1 

mm stalk. The carpels appear to have an abaxial vein 

with a closed adaxial suture extending most of the 

carpel length. Each fruit, as far as can be 

determined at present, appears to bear a single seed, 

and the entire fruit seems to be deciduous at matur- 

ity. The longest axis fragment we have bears an 

estimated 2,700 fruits. Each gynoecium is subtended 

by one whorl of about ten very small, rounded scars. 

This angiosperm reproductive material has features 

similar to some families of presumed primitive di- 

cotyledons and monocotyledons. 

KUPMAN, MARIE 

H. Department of Botany, The 

Ohio State University, Columbus, OH 43210. - 

The ultrastructure of pollen extracted frcm 

Boulaya fertilis. 

The genus Boulaya (Carpentier) was characterized 

in detail by Halle in 1933 for impression- 

ccpression specimens of pollen organs associated 

with the'mredullosan pteridosperms. Specimens are 

pyriform and consist of several fused sporangia 

that may extend up to 2.0 cm in length. Well-

preserved specimens possess "teeth" that probably 

correspond to the free ends of the pollen sacs. 

The specihens used in this study were borrowed 

fran the British Museum (Natural History) and 

appear to consist of a variable number of 

sporangia, with 8 being the most common number. 

Pollen grains are of the Monoletes type and range 

frcm 230-280 um in length. On the proximal 

surface is a monolete suture; distally the grains 

possess two longitudinal grooves. The sporoderm 

is two parted consisting of a hamDgeneous nexine 

with conspicuous lamellae, and an outer alveolate 

sexine up to 6 um in thickness. In this study the 

ultrastructure of the pollen is compared to other 

Monoletes-type grains extracted fron pollen organs 

of the Halletheca and Aulacotheca morphological 

types. 

LA PASHA, CONSTANTINE A. Department of Botany, 

University of Montana, Missoula MT 59812. 

- Rhombostrobus cliffwoodensis - a taxodiaceous 

seed cone from the Upper Cretaceous of New Jersey. 

Description of Rhombostrobus cliffwoodensis was 

originally based on a single fragmentary pyritic seed 

cone. A new pyritic specimen of a more complete cone 

from the Magothy Formation, Cliffwood, New Jersey 

adds to the understanding of this species. The new 

cone is 3 cm diam and at least 4 cm long and lacks 

apex and base. The axis is 10-12 mm diam. The pith 

is 4.5-5.0 mm diam and is composed of 28-40 pm diam 

parenchyma cells. Xylem forms a cylinder 0.8-1.1 mm 

thick and lacks resin canals. Tracheids of the vascular 

cylinder are uniform, slightly rounded, 9-18 pm 

diam, and form radial files. The cortex is 1-2 mm 

thick and has a single ring of resin canals surrounding 

the xylem. Bract-scale complexes that are 3 mm 

thick, 8 mm wide, and 10 mm long are inserted normal 

to the axis in a helical arrangement. The complex 

trace is adaxial to the single row of major resin 

canals in the complex, and forms a broad band or 

separate bundles. A single resin canal enters the 

complex from the cortex and divides distally. Two 

winged seeds are produced in shallow depressions on 

the adaxial surface of the complexes. 

The new material clarifies some of the details of 

the cone axis and bract-scale complex vasculature. 

This information allows more precise comparisons with 

other members of the Taxodiaceae. These comparisons 

confirm the previous interpretations of the relationship 

of this species to other members of the Taxodiaceae. 

Rhombostrobus cliffwoodensis combines 

features of seed cones typical of Sequoia with those 

typical of Cunninghamia. 

LEARY, RICHARD L. Geology Department, Illinois 

State Museum, Springfield, IL 62706. - New fossil 

algae from Valmeyeran (mid-Mississippian) strata 

of Illinois. 

Two previously unknown algal forms are preserved as 

carbonaceous films and impressions in basal St. Louis 

Limestone (Valmeyeran) of Jersey County, Illinois. 

One form consists of broad (1.5 cm) branching thalli- 

with papillae ca. 1 mm in diameter. Although none of 

the characteristics used to classify extant algae 

(cellular structure, pigment, reproductive cycles, 

food storage substances, etc.) are preserved, these 

algae are thought to belong to Rhodophyta (red algae) 

and have morphologic similarities with some species 

of Gigartinacea. 

A second form is by far the most abundant and best 

preserved. It consists of elongate blades up to 6,8 


cm long, 1 cm wide, with rounded apices and tapered 

bases. The blades were probably inflated and the 

bases frequently had pneumatocysts 1 mm in diameter; 

as many as 7 pneumatocysts were observed on a single 

blade. The blades were attached spirally to stipes up 

to 0.9 cm in diameter. The stipes bifurcated dichoto- 

mously. They were probably attached to an expanded 

holdfast. This algal form has similarities with 

certain Phaeophyta (brown algae), in particular 

Laminariales such as Macrocystis . 

The fossils are abundant in several quarries in 

western Illinois - eastern Missouri. The algae are 

associated with conularia, an animal with a cone- 

shaped exoskeleton. The algae and conularia probably 

grew in shallow marine water on the eastern flank of 

the Ozark Dome. This region would have been at ca. 

latitude 200 south during Valmeyeran time. 

LESNIKOWSKA, A. D.* and M. A. MILLAY. Botany Department, 

University of Illinois, Urbana, IL 61801, 

and Botany Department, University of Maryland, 

College Park, MD 20742. - Cladistic analysis of 

fossil and extant marattialean ferns. 

A preliminary cladistic analysis of living and fossil 

marattialean ferns has revealed a pattern of relationship 

that serves to indicate areas of future 

research. WAGPROG was used to construct a consensus 

tree for 38 taxa based on 38 characters. The analysis 

was rooted using the ferns Musatea (Zygopteridales) 

and Ankyropteris (Filicales) as the outgroup. 

The extant taxa were linked together in the middle of 

the cladogram near Millaya and Eoangiopteris while 

the most derived Paleozoic taxa occurred in the 

Latifolia and Minor groups of Scolecopteris. Some 

examples are noted in which parallelisms or reversals 

in several characters are required, suggesting that 

at least some of the character states of some of the 

OTUs involved are not homologous. In one example 

discussed, the cladogram suggests the simultaneous 

evolution of a suite of vegetative characters in the 

ancestor of the extant taxa, together with several 

reversals in synangium characters. A more parsimonious 

explanation would be provided by the occurrence 

- currently unknown - of non-arborescent members of 

several Paleozoic lineages. Without such a hypothesis 

such marattialeans, if they exist, might not 

be recognized. Thus the hypotheses represented by 

the cladogram provides a conceptual framework for 

the integration and evaluation of new information as 

well as indicating areas of future research. 

MAHLBERG, 

PAUL G. , AND DONALD W. FIELD. 

Department of Biology, Indiana University, 

Bloomington, IN. 47405. - Fossil laticifers from 

Eocene brown coal deposits of the Geiseltal. 

Cellular remains from brown coal deposits of the 

Geiseltal, near Halle, were determined to be 

fossilized nonarticulated laticifers. The thick 

mats of intact cells consisted of strands of 

rubber. These celLs, often with cell wall remains 

surrounding the strand of rubber, retained a 

tubular shape during preservation. Small holes, 

possibly artifactual, occurred at irregular 

intervals along the surface of some of the cells. 

The laticifers viewed in trans- or longisection 

were composed of a dense, yet poriferous, 

isoprenoid content originally present in the cell. 

The porous interstices represented areas of 

protoplasm, now absent. Various configurations in 

the rubber, as spherical surfaces, represented


surface images, in negative relief, of former 

nuclei and organelles. The laticifer axes 

possessed branches of various configurations 

comparable in morphology to those of laticifers in 

extant plants. Acetone extracts of the laticifer 

contents, analyzed by gas-liquid chromatography, 

demonstrated the presence of several triterpenoids 

which formed a characteristic profile for these 

remains. This profile resembled the triterpene 

profiles from latex of extant Euphorbia where they 

represent a fingerprint for a taxon. The cellular 

morphology and triterpenoid profile of these fossil 

laticifers may be employed effectively as markers, 

in comparative studies with extant plants, to 

identify the species of origin of these 

laticifers. 

MANCHESTER, STEVEN R. Department of Geology, 

Indiana University, Bloomington, IN 47405 - 

Eocene fruits, wood and leaves of the Fagaceae 

from the Clarno Formation of Oregon. 

The Middle Eocene Nut Beds locality of the Clarno 

Formation in central Oregon has yielded a variety of 

fagaceous remains, including the earliest known 

acorns, two types of wood and two types of foliage. 

The acorns, preserved as casts, are longitudinally 

striate rounded nuts 13-15 mm in diameter and about 

18 m long, capped by a basal involucre covering 

about 1/3 of the nut. Similar acorns occur today in 

both Lithocarpus and Quercus. Silicified wood of 

Quercinium crystallifera Scott & Wheeler is semiring-porous 

and has large vessel elements, vasicentric 

tracheids and both uniseriate and large aggregate 

rays. Ths wood is anatomically similar to that 

of extant Quercus and Lithocarpus. The other wood, 

Fagaceoxylon ostryopsoides Scott & Wheeler, is 

characterized by diffuse-porosity, pores in radial 

multiples and in flame-like tracts, vasicentric 

tracheids and exclusively narrow, but sometimes 

aggregate, rays. Although identical anatomy has 

not been observed in modern species, the wood most 

closely resembles that of extant Castanoideae. The 

two types of leaves both have evenly spaced craspedodromous 

secondary veins leading directly into simple 

teeth with shallow (2-3 mm) sinuses and closely 

spaced percurrent tertiaries. In one type the teeth 

are gently rounded and non-spinose, suggesting 

affinity with Quercus. In the other type the teeth 

are spinose, as in some modern Quercus and Castanoideae. 

Together, these fossils document at least two 

distinct but sympatric fagaceous genera in the Clarno 

flora. 

MANCHESTER, STEVEN R. Department of Geology 

Indiana University, Bloomington, IN 47405 - 

Fruits and seeds of Tapiscia (Staphylaceae) from 

the Middle Eocene of Oregon. 

Silica casts of fruits and seeds representing Tapiscia 

are common in collections from the Middle Eocene Nut 

Beds locality of the Clarno Formation in central 

Oregon. The seeds are subglobose, 4-5 mm long, 3-4 

mm wid, rounded dorsally and basally, pointed at the 

micropylar end and concave ventrally. The ventral 

side is dominated by a circular, recessed chalazal 

scar, 1.2-1.8 mm in diameter. The exterior of the 

seed is longitudinally striate. The fruits are 

globose, about 6 mm long and 5 mm wide, with a penicarp 

of uniform thickness covering the seed and 

having a finely verrucate surface. In the features 

observable, the specimens are almost indistinguishable 

from those of extant Tapiscia sinensis Oliv. Although 

the single extant species of Tapiscia is confined to 

China, this North American occurrence supplements 

those recognized in England and Germany indicating 

that Tapiscia, like other modern genera of the 

Staphylaceae, was geographically widespread in the 

early Tertiary. 

MAPES, GENE. Department of Botany, Ohio 

University, Athens, OH 45701 - Permineralized 

Lebachia pollen cones. 

Permineralized conifer pollen cones conforming to 

Lebachia Florin are described from Hamilton, Kansas. 

The fossiliferous limestone occurs an an Upper 

Pennsylvanian/Lower Permian channel deposit in the 

Virgilian Shawnee Group. Cuticle from the cones has 

1-2 broad parallel bands of stomata, marginal uniser- 

iate hairs, and papillae. Pollen cones are compact, 

ellipsoid to cylindrical, and borne as single termi- 

nal units on leafy lateral or ultimate branches. 

Mature cones average 0.6 cm wide x 2.0 cm long, 

though some are up to 10 cm. Cone organization is 

simple, not compound. Sporophylls are spirally 

arranged on non-woody axes, avg. 0.1 cm diam. Indi- 

vidual sporophylls display an attenuated tip, entire- 

dentate margin, and distinct abaxial heel; each spor- 

ophyll bears an adaxial cluster of approximately 5-10 

elongate pollen sacs containing Potonieisporites 

grains. Sporangial walls average 1-2 cells thick 

with no specialized cells for dehiscence. Although 

Lebachia pollen cones have been previously interpre- 

ted as Pinus-like, with two abaxial sporangia, the 

Hamilton Lebachia cones are more comparable to cer- 

tain Mesozoic voltzialean taxa such as Darneya 

Schaarschmidt and Maubeuge emend. Grauvogel-Stamm. 

The structure of these Lebachia clarifies our under- 

standing of conifer phylogeny and indicates that 

pinaceous pollen cone organization is not as primi- 

tive as currently believed. 

MAPES, G.* and R.H. MAPES. Department of Botany 

and Department of Geological Sciences, Ohio 

University, Athens, OH 45701 - Distribution of 

Mississippian age plants in the Fayetteville 

Formation. 

Permineralized and compressed plants from the 

Fayetteville Formation in Arkansas fill an important 

gap in paleobotanical characterization of North 

American upper Mississippian strata. The 

Fayetteville plants are most comparable to Lower 

Carboniferous taxa from Czechoslavakia, England, and 

Scotland. Ammonoid cephalopods from Fayetteville Fm. 

confirm Middle Chesterian age and European biostrati- 

graphic equivalence to E1, Pendleian Stage, Namurian 

A. In northern Arkansas, the Fayetteville outcrops 

along an east-west trend; the lower portion is thick 

black shale with an excellent invertebrate fauna and 

permineralized flora. In northwestern Arkansas, the 

upper Fayetteville Fm. includes the deltaic Wedington 

Sandstone Member with interbedded coals and terres- 

trial shales. The Wedington compression flora con- 

tains in situ root traces and casts, large radial 

seeds, arthrophytes, lycopod branches and cones, fern 

and seed-fern foliage, and lyginopterid fertile axes. 

Permineralized plants are from the lower Fayetteville 

Fm. and include lycopod branches, roots, and cones, 

lyginopterid, calomopityean and medullosan seed-fern 

axes, coenopterid fern petioles, and arthrophytes. 

Lateral floral distribution varies quantitatively and

qualitatively: lycopods diminish in numbers, east of 

the delta, as total diversity and numbers of gymno- 

spermous remains increase. Paleofloristic interpre- 

tations are hampered by differential preservational 

modes, but several lines of evidence, including pa- 

leocurrent data, suggest the Wedington deltaic system 

influenced plant transportaion and subsequent distri- 

bution along the southern flanks of the Ozark dome 

during early Upper Carboniferous time. 

MELCHIOR, Robert C.*, and HALL, John W., Dept. of 

Biology, Bemidji State University, Bemidji, MN 

56601 and Dept. of Botany, University of Minn., 

220 Biological Sciences Center, 1445 Gortner Ave., 

St. Paul, MN 55108 - Geological observations on 

t.Ae occurrence of some Paleocene Megaspores and 

allied forms. 

An analysis of the sedimentology of the 1?annagan 

Creek Site (Paleocene, North Dakota) has contributed 

to an understanding of the modes of occurrence of 

Dictyothylakos.;Horst, Minerisporites mirabilis (Miner) 

Potonie (i.e. Isoetites horridus (Dawson) Brown and 

Azolla stanleyi Jain and Hall. The stratigraphy 

of the site consists of three units, 1) a lower sandy 

silt representing deposition by a slow moving stream, 

grading into 2) an overlying black organic shale 

suggesting lacustrine sedimentation, and 3) an upper, 

disconformable graded siltstone indicating a crevasse 

splay. The sequence is characteristic of a chute 

cutoff which was gradually isolated to become a lake 

that was ultimately filled by an overbank crevasse 

splay. Dictyothylakos, which is interpreted as a 

hydropsychid (caddisfly) larval feeding device, is 

restricted to the stream deposit. M. mirabilis is 

found predominantly in the lake deposit as is A. 

stanleyi although reduced populations of both types 

are also found in the upper (gradational) beds of the 

stream deposit as well. Megafossils of I. horridus 

are found presumably in place in the upper stream 

deposit in water less than 1 m deep. Vegetative re- 

mains of A. stanleyi from the site bear anomalous 

megaspores, without float apparatus, that resemble 

megaspores of Salvinia, and M. mirabilis exhibits a 

high degree of variability. These phenomena could 

conceivably lead to errors in identification and 

paleoecological interpretation. 

MICKLE, JAMES E.* and RICHARD L. LEARY. Illinois 

State Museum, Springfield, IL 62706. Aulacotheca 

from the Early Pennsylvanian of the Illinois Basin. 

Compressed synangia referable to the medullosan 

pollen organ Aulacotheca have been discovered in 

Early Pennsylvanian sediments from Rock Island Co., 

IL. Specimens were recovered from channel fill 

shales containing floral elements suggesting an 

upland environment. Based on synangial size and 

morphology, sporangial number, and prepollen type, 

two distinct, new forms are recognized. Synangia of 

the first form are 11-17 X 2.5-4.0 mm and have 4-6 

sporangia. Free sporangial tips are acutely 

pointed. Dehiscence is through a longitudinal slit 

to the inside of the synangium. Prepollen averages 

181 X 129 um and has a monolete suture with median 

deflection. Sexine on proximal and distal surfaces 

shows narrow, closely-spaced, anastomosing inpockets; 

distal and lateral walls are separated by a deep, 

encircling fold. Synangia of the second form are 

21-29 X 3.8-5.5 mm and apparently have 4 sporangia. 

Distally, free sporangial tips have a narrow 

extension, giving a mucronate appearance. Features 

of these synangia suggest that greater morphological 


diversity in synangial and pollen structure occurs 

in Aulacotheca and the medullosan pteridosperms than 

previously recognized. 

MILLAY, M.A.* and J. GALTIER. Botany Department, 

University of Maryland, College Park, MD 20742 and 

Lab de Paleobotanique et Evolution des Vegetaux, 

Universite des Sciences et Techniques du Languedoc, 

Place E. Bataillon, 34060 Montpellier Cedex,France. 

- A species of Scolecopteris (Marattiales) from 

Grand'Croix (France) resembling Renault's Ptycho- 

carpus. 

A new species of Scolecopteris is described from 

silicified permineralizations from the Stephanian of 

Grand'Croix (France). Material consists of radial 

synangia attached to poorly preserved pinnules. Syn- 

angia are circular in cross section (average 0.8 mm 

diam and 1.0 mm long) and composed of 4-7 sporangia 

that surround a central cellular area in the basal one 

half. Sporangia are tubular (0.25 mm diam) and taper 

distally into deltoid tips that close off the synan- 

gium interior prior to dehiscence. Spore release in- 

volves the lateral separation of sporangia distally 

and the rupture of cells along the inner sporangium 

midline. Outer facing walls are parenchymatous with 

a distinctive epidermis. Synangial pedicels are 

short, parenchymatous, and broad (0.6 mm diam), with a 

central area of thick walled cells. Pinnule margins 

are entire, downturned, and extend to near the syn- 

angium apices. Spores are reniform (average 22 x 13 

pm), monolete, and have an ornamentation of small ir- 

regular grana. Comparisons are made with material 

from Autun described by Renault under the name Ptycho- 

carpus Weiss, and previously only illustrated in line 

drawing form. Examination of Renault's specimen 

suggests the possible identity of these two forms. 

The new species is most similar to Scolecopteris 

altissimus and S. altus, but differs from these 

species in pinnule morphology and possession of a 

broad pedicel. 

MILLER, CHARLES N., JR. Department of Botany, 

University of Montana, Missoula, MT 59812. A new 

species of Pinus based on seed cones from the Late 

Cretaceous of New Jersey. 

The new species is based on two specimens of semifusinized 

cones from the Magothy Fm. (Santonian - 

Campanian) exposed at the classic Cliffwood locality 

on Raritan Bay. The cones are ovoid-conical and are 

3-4.5 cm. long by 2.2-2.3 cm. at their widest 

diameter. The ovuliferous scales are up to 9 mm. 

wide and are 12 mm. long. The scale apex is inflated 

and terminates in a rhomboidal apophysis that has a 

centrally located umbo. There is no evidence of a 

spine on the umbo. Several anatomical features 

further support the assignment of the new species to 

Pinus. These are the union of the vascular traces to 

each bract and associated scale where they diverge 

from the vascular cylinder of the cone axis, the 

restriction of the resin canals of the scale base to 

tissues abaxial to the vascular strands, and the 

separation of the scale and subtending bract so that 

they are free marginally before they are nmedially. 

These anatomical features occur in combination with 

inflated scale apices only in cones of Pinus. Within 

this genus the fossil cones compare most favorably 

with cones produced by species of the Subgenus Pinus. 

The parenchymatous construction of the cortex of the 

cone axis in the fossils precludes assignment of the 

new species to the subsections Contortae, Oocarpae, or 

Sylvestres of the Section Pinus. Thus, the fossil 

cones belong to one of the remaining subsections of


the Section Pinus or the Section Ternatae. However, 

our knowledge of the comparative cone anatomy of 

modern species of these taxa is insufficient to permit 

a more precise identification of the fossil within 

this group. 

NIKLAS, KARL J. Division of Biological Sciences, 

Cornell University, Ithaca, NY 14850. - Evidence 

for a conducting strand in non-vascular land 

plants from the early Silurian (Llandoverian) of 

Virginia. 

Data are presented for elliptical, bifurcate, to 

irregular compression fossils of Llandoverian age 

from the Massanutten Formation of Virginia. The 

fossils range from 0.45 to 10 mm in diameter (1.32+ 

0.51 mm, n = 122). Maceration of compressions L' 2.4 

mm in diameter yield surficial cellular remains, 

while larger compressions yield smooth walled and 

banded tubular elements. Strands of cells, internal 

to surficial cellular outlines, were isolated from 

large compressions. SEM of cellular strands reveal 

peripheral smooth walled tubes (17?6.9 pm in diam.), 

with hemispherical or conate end walls, surrounding 

banded tubes (16.8?2.1 pm in diam.) 

A 6C'3-value of -25.6 determined for duplicate 

samples is consistent with a terrestrial origin of 

the organic material. The influence of methanogenic 

bacterial action attending or following burial cannot 

be ruled out, however. 

The anatomy and morphology of the cellular strands 

found in these Massanutten fossils is inconsistent 

with those of present-day moss hydromes, but shares 

features with the conducting strands of some early 

Paleozoic plants. 

PIGG, KATHLEEN B. and GAR W. ROTHWELL, 

Department of Botany, The Ohio State University, 

Columbus, Ohio 43210, and Department of Botany, 

Ohio University, Athens, Ohio 45701.- Development 

and surface configurations of the 

Paleozoic isoetalean Chaloneria. 

A large number of lycophyte stems have been 

observed on split surfaces of coal balls from the 

Duquesne Coal, outcropping west of Steubenville, 

Ohio. Surface features conform closely to several 

genera including Chaloneria, Asolanus, Stigmaria, 

and Knorria. When sectioned, all of the specimens 

have been found to represent different 

developmental stages and decortication levels of 

Chaloneria cormosa Pigg and Rothwell. When the 

stem surface and leaf bases are present the 

specinmens may be identified as Chaloneria, but 

when the leaf bases are absent or abraded a 

Stigmaria-like configuration is produced. If the 

specinen splits midway through 

stem with secondary cortical 

the cortex 

development 

of a 

an 

Asolanus configuration results, but if the split 

occurs at the level of the periderm a Knorria 

pattern is produced. The various specimrens 

provide a basis for characterizing secondary 

cortical development in Chaloneria, and for 

ccxparing it to similar develo4ment in Isoetes. 

The material also allows for mrore precise 

interpretation of the affinities of Asolanus and 

other poorly known Carboniferous lycophytes such 

as Cyclostigma and Bothrodendron. 

POSNICK, ALLAN E., ANDREW E. KASPER, JR.* 

AND WILLIAM 1I. FORBES. Department ot 

Botany, Rutgers University, Newark, N.J. 

07102 and Division cf Mathematics and 

Science, University of Maine, Presque Isle 

Me. 04769. - Plant fossils of Bvtinophyton 

ichaAd6oni from the Upper Devonian Perry 

Formation of eastern Maine. 

New collections from the Upper Devonian 

Perry Formation in eastern Maine have resulted 

in a better understanding of the 

morphology of Barinophyton richardsonii 

(Dawson) Wlite, 1905. B. richardsonii, the 

type species of the genus, is based on only 

a few fragmentary specimens and is known 

solely from the Perry Formation. The original 

specimens were first assigned to 

Lepidostrobus then Lycopodites by Dawson 

1 861, 1863). In i905 White established a 

new genus, Barinophyton, for the material. 

The fossils are preserved.as compressions 

and show fertile axes bearing strobili. The 

largest specimen, although incomplete, is 

12 cm long and bears 12 strobili. The 

plants consist of unornamented and unbranched 

axes 5-6 mm wide. The sessile strobili are 

attached alternately and distichously along 

the axes, lie at a 450 angle, and are spaced 

7-8 mm apart. The largest strobilus, 

although incomplete, is 3.4 cm long. The 

strobilar axis bears numerous appendages and 

sporangia on its adaxial surface. In strobili 

compressed in adaxial-abaxial orientation 

two rows of appendages are evident. The 

new collections have provided the most complete 

fertile specimen to date. It is speculated 

that the Barinophytales arose from 

zosterophyllophyte ancestors. 

RETALLACK, 

GREG. J. Department of Geology, 

University of Oregon, Eugene, Oregon 97403 

- Factors in the origin of North American prairie. 

The fossil record of prairie vegetation is poor, bec- 

ause of its usual dry and well-drained habitats, in 

which plant fossils are seldom preserved. The devel- 

opment of prairie during the Tertiary has been inter- 

preted from fossil phytoliths and other hard parts of 

plants, as well as from fossil mammalian remains. Fos- 

sil soils are additional evidence for the timing and 

factors involved in the origin of prairie vegetation. 

A sequence of Late Eocene and Oligocene, fossil 

soils in Badlands National Park, South Dakota, is evi- 

dence of change from woodland (on paleudalf fossil 

soils), to savanna (on andic ustochrepts) dissected 

by streamside gallery woodland (on paleustalfs) and 

finally to prairie (on calciorthids and ustollic eutr- 

andepts). Prairie vegetation appeared by the time 

climate had dried to semiarid, as interpreted from 

calcic horizons at shallower depth, less clay, lower 

quartz/feldspar ratios and hues changing from reddish 

to yellowish in fossil soils stratigraphically higher 

in the sequence. Increased openness of vegetation 

appears to have corresponded to increased rate of 

sediment accumulation, perhaps an indication of a 

more unstable landscape. Fire does not appear to have 

been important in the development of prairie from 

savanna, because charcoal is preserved even in well-- 

drained soils, and none was found in the fossil soils. 

Grazing activity is unlikely to have been important 

for the appearance of prairie, because changes in

associated mammalian fossils are minor compared to 

changes at other stratigraphic levels, and because 

the fauna remained savanna-adapted. Plant competition 

was probably unimportant for these early, aridland 

prairies, because patterns of root traces, peds and 

cutans in their fossil soils are indications that 

herbaceous plants were generally well-spaced. 

RIGGS, SUSAN D. Department of Botany, Ohio 

University, Athens, Ohio 45701 - A complex cone of 

putative sphenophyllalean affinities from the 

Upper Pennsylvanian of the Appalachian Basin. 

A cone with whorled appendages and distinctive mono- 

lete spores has been discovered in coal balls from 

the Duquesne Coal west of Steubenville, Ohio. The 

cone is up to 13.5 mm in diameter and has a distinct- 

ly triangular axis in internodal regions. Near the 

base the axis has a triarch, exarch protostele ap- 

proximately 0.5 mm in diameter. Distally the meta- 

xylem is not differentiated at the center, such that 

there are three exarch bundles. Approximately six 

appendages diverge at each node. Most of these are 

slender, but a few are flattened and bract-like at 

the base. Distally, all appendages branch to produce 

terminal sporangia, slender spine-like tips, or both. 

The sporangia are spheroidal, 0.6-0.8 mm in diameter, 

and have a thin wall. In section view the wall cells 

form a uniseriate palisade. There is no obvious de- 

hiscence mechanism. Spores have distinctive large 

ridges that are interconnected by smaller ridges, and 

are similar to Striatosporites Bhardwaj and 

Columnisporites Peppers. Among presently known 

sphenophyllalean cones the specimen compares most 

favorably with the Upper Devonian Eviostachya 

Leclercq. 

RISCHBIETER, MICHAEL,* BEN M. STIDD and TOM L. 

PHILLIPS. Dept. of Biological Sciences, Western 

Illinois University, Macomb, IL 61455 and Dept. 

of Botany, University of Illinois, Urbana, IL 

61801.--A new seed fern pollen organ from the 

Pennsylvanian of Kentucky. 

A new seed fern pollen organ is present associated 

with vegetative remains of Schopfiastrum in coal 

balls collected at the Providence, Kentucky, 

locality. Sporangia are clustered in groups of 7-9, 

connate basally but separated for most of their 

length. The bulk of the sporangium wall is composed 

of a prominent layer of elongate thick-walled cells 

covered by a uniseriate epidermis. Sporangial tips 

are beaked and composed of the thick-walled cells. 

The synangia are vascularized but the course of the 

vascular tissue is not yet determined. Pollen is of 

the lyginopterid type, 30 um in diameter and trilete. 

The exine is alveolate/tectate with a prominent 

nexine; surface ornamentation is densely verrucate/ 

rugulate. 

ROBERTSON, EDDIE B. Phillips Petroleum Company 

Bartlesville, Oklahoma 74004 

- Paleocene palynology of the Missouri Breaks. 

Pollen and spore assemblages are established for the 

Paleocene deposits exposed along the Missouri Breaks 

of western North Dakota. A sequential series of 

sections sample Maastrichtian to Early Eocene sediments 

along the valley of the Little Missouri River. 

Sections are taken from the Hell Creek, Tullock, Lebo, 

Tongue River, Sentinel Butte and Gol den Vall1ey Formations 

. The assemblages are establ ished using a com- 


bination of fossil indices and agglomeration techni- 

ques. The assemblages of the Paleocene of the 

Williston Basin in western North Dakota are unique. 

They show a close relationship to those described by 

Leffingwell in the basins to the south and to a 

lesser extent to the palynofloras described by Rouse 

from the Paleocene of western British Columbia. 

ROTHWELL, G.W. Department of Botany, Ohio 

University, Athens, Ohio 45701 - An indusiate 

filicalean fern with gradate soral development 

from the Upper Pennsylvanian of the Appalachian 

Basin. 

A large 

surface 

number of indusiate sori occur on the abaxial 

of pinnules produced by an Anachoropteris 

clavata-type frond. The indusium is cyatheoid, 

either completely enclosing the sporangia or open at 

the apex. Sporangia are attached to an elongated and 

vascularized hymenophylloid receptacle that is 

oriented parallel to the pinnule surface. Individual 

sporangia have a bi- or triseriate ring-like annulus 

and a narrow stalk. In some specimens all the sporangia 

are located close to the receptacle, while the 

terminal sporangia of others have much elongated 

stalks. Still other sori lack sporangia in the 

apical region, and this range of variability provides 

the basis for interpreting gradate development. 

Spores are radial and trilete with concave interradial 

sides, and exhibit spinules on both proximal 

and distal surfaces. Material of this type expands 

our knowledge of variability within the most primitive 

filicaleans, and provides an additional basis 

for interpreting 

group. 

evolutionary radiation within the 

ROTHWELL, G.W. Department of Botany, Ohio 

University, Athens, Ohio 45701 - Functional morphology 

in ovule development, and the evolution of 

gymnospermous reproduction. 

Lagenostomalean ovules are the best currently available 

evidence for interpreting reproductive biology 

among the most primitive gymnosperms. Different 

species show a greater degree of structural variability 

than generally recognized, but common features 

of the pollen chamber unite them into a single group 

and indicate a monophyletic origin of seed plants. 

Similarities in pollen chamber structure and function 

have been obscured by a morass of conflicting and inconsistently 

applied terms that refer to the various 

parts. Although specimens typically show a narrower 

range of ontogenetic variability than do other 

Paleozoic ovules, 

and the discovery 

a comparison of different 

of ovules in both earlier 

species 

and later 

stages than generally encountered now provide a basis 

for interpreting many features of lagenostomalean 

reproduction. The differences exhibited by other 

Paleozoic ovules provide a basis for recognizing the 

occurrence of trigonocarpalean reproduction at the 

base of the Namurian, cardiocarpalean reproduction at 

the base of the Westphalian, 

duction by Westphalian D. 

and conifer type repro- 

SCHECKLER, STEPHEN E.* and JAMES F. BASINGER. Dept. 

Biology, VPI&SU, Blacksburg, VA 24061 and Dept. 

Geol. Sci., Univ. Saskatchewan, Saskatoon S7N OWO. 

- Late Devonian Archaeopteris fissilis from northernmost 

ancient Laurentia, eastern Yukon, Canada. 

Lower Earn Group turbidites yield an A. fissilis 

(99%) flora. This is its first record in North Amer-


ica; A. fissilis is found elsewhere only at Ellesmere 

and Donetz. Other floral elements are A. macilenta, 

an herbaceous lycopod, and a possible aneu'rophytalean. 

These and associated conodonts support an early-mid 

Frasnian age. Archaeopteris fissilis bears crowded 

helices of decurrent leaves on all branches. Non-laminate 

leaves are 2-3 times forked, planated, and are 

smaller distally. Those on penultimate branches are 

2-2.5 cm long while sterile leaves on the 2-ranked 

ultimate branches are 0.8-1.2 cm long. Portions of 18 

fertile strobili show that fertile leaves are smaller 

(0.8-1 cm long), bear dense clusters of sporangia 

(1.8-2 mm, but up to 3 mm long by 0.6-0.7 mm wide) on 

the upper surface, and that A. fissilis is heterosporous 

and monoecious. Two incomplete strobili show that 

most fertile leaves are unisexual. All but the distal 

few are megasporangiate. Megasporangia contain 32-64 

megaspores (190-220 jim, but up to 280 pum). Microsporangia 

are similar in size, but contain hundreds of 70- 

80 ,im microspores. Penultimate and ultimate branch 

anatomy is similar to other Archaeopteris. These data 

support retention of A. fissilis in Archaeopteris and 

suggest that leaf lamination is insufficient to distinguish 

this genus from Svalbardia. Although A. 

fissilis suggests the origin of laminate leaves of 

Archaeopteris from non-laminate precursors, this condition 

may relate more to its ecology. Yukon, Ellesmere, 

and Donetz are all at reconstructed Frasnian 

paleolatitudes of 300 N, a desert latitude. This suggests 

that A. fissilis leaves may have been reduced 

for xeric adaptation, rather than retaining the ancestral 

condition of older progymnosperms. 

SCHOPF, J. WILLIAM* and ROBERT MIKAWA. Department 

of Earth and Space Sciences and Institute of 

Geophysics and Planetary Physics, University of 

California, Los Angeles, CA 90024. - Precambrian 

stromatolitic microbiotas of the Gaoyuzhuang 

Formation of northern China. 

Two communities of diverse, well-preserved, fossil 

prokaryotic microorganisms have been detected in 

petrographic thin sections of carbonaceous cherts 

from the 1,400-1,500 Ma-old Gaoyuzhuang Formation 

at the stratotype section of the "Sinian Suberathem" 

near Jixian, 100 km east of Beijing, in northern 

China. One of these communities is preserved in 

bedded, essentially flat-laminated, stromatolitic 

chert; the other occurs in silicified conical 

stromatolites of the forms Conophyton cylindricum 

and C. garganicum. These newly discovered 

microfossils comprise two of only a very few 

permineralized microbiotas now known from the 

Precambrian of China and are among the first such 

fossil biocoenoses to be detected in the Sinian 

stratotype section. Comparison of the two 

assemblages is of considerable biostratigraphic 

interest, providing an unusual opportunity to assess 

the role of environment and ecologic setting in 

influencing the biologic composition and diversity 

of similarly aged and comparably preserved Pre- 

cambrian microbial assemblages of this type. 

SCHWARZWALDER, ROBERT N. Department of Biology, 

Indiana University, Bloomington, IN '47405. -The 

use of multivariate 

atics . 

statistics in paleosystem- 

Classification systems of fossil plants are often 

inadequate, especially in cases of problematic 

groups or when the characteristics available for 

analysis 

Fossil 

are of unknown phylogenetic significance. 

taxa are often erected from small groups of 

specimens without sufficient attention to variation 

among and between taxa. The resultant classifica- 

tion schemes contain species which represent points 

on a structural continuum and are established by ar- 

bitrary criteria, such as differences in size or 

variations in shape, which subdivide the specimens 

but may or may not have any real significance. The 

use of multivariate statistics can facilitate 

paleosystematic studies by: providing a determina- 

tion of continuous versus discrete variation in 

characters; ascertaining the most useful 

characteristics for classification of specimens; 

and, providing hierarchical groupings of taxa. 

Using sandstone impressions from the Dakota forma- 

tion of Kansas and Nebraska, three multivariate 

statistical methods - discriminant analysis, cluster 

analysis, and multidimensional scaling - have been 

applied and evaluated as paleosyst4matic tools. 

Multivariate statistics, mostly cluster analyses, 

have been previously utilized in paleobotanical 

studies; however, despite their potential these 

methods have not enjoyed widespread acceptance in 

the field. Phenetic systems can provide meaningful 

hierarchical classification systems, and while they 

may require additional analysis before phylogenetic 

conclusions may be drawn, they are consistent with 

the form taxon concept commonly utilized in pale- 

obotany. 

SHEN-MILLER, J.*, J. WILLIAM SCHOPF & R. BERGER. 

Department of Chemistry and Biochemistry, and 

Institute of Geophysics and Planetary Physics, 

Univ. Calif., Los Angeles, CA 90024 - Germination 

of a ca. 700 year-old lotus seed from China: evi- 

dence of exceptional longevity of seed viability. 

In 1952, seeds of the sacred lotus (Nelumbo nucifera 

Gaertn.) were collected by Chinese scientists from 

silt 1-2 m below the surface of an ancient dried pond 

at Paozi Tun Village in Xinjin County ("Pulantien"), 

Liaoning Province, P.R.C. In 1955, studies at the 

Beij ing Botanical Garden demonstrated that these seeds 

were viable; one of the plants then germinated was 

still growing when we visited Beijing in 1982. Analy- 

ses in 1975 at the Institute of Archeology in Beijing 

yielded a radiocarbon age of 915+80 years for a pooled 

sample of these seeds untested for viability. Xinjin 

seeds were provided us by Zhang Yi-jun of the Beijing 

Botanical Garden. An initial study was carried out on 

two seeds (X-1 and X-2), characteristics of which are 

compared below with those of a seed (M-1) from modern 

progeny of Xinjin lotus, obtained from H. V. Wester of 

the National Park Service, Washington, D.C. 

X-1 X-2 14-1 

Length (mm) 17.0 15.5 17.0 

Girth (mm) 8.5 8.0 9.0 

Dry Weight (g) 0.69 0.83 0.94 

Appearance shiny shiny dull 

Germination Time (d) no yes, 6 yes, 4 

Seeds were germinated in the dark; X-2 was immediately 

dried in an oven (110 C, 24 h) and stored in a desic- 

cator. Subsequent radiocarbon dating yielded an age 

for this seed (UCLA-2387B) of 705+165 years. This 

appears to be the oldest viable seed for which a radio- 

metric age has been directly determined. Comparisons 

of two more ancient seeds.with those of modern Xinjin 

lotus are in progress. 

SmTxo, E.L. Department of Botany, Thie Ohio 

State University, Columbus, OH 43210. 

- Phloem anatomy and trends of specialization 

in the Pennsylvanian seed fern Medullosa 

Stems of the seed fern Medullosa with well- 

preserved phloemn are described from coal ball

specinmens ranging in age from early/middle to late 

Pennsylvanian. Phloem appears to be continuous 

with the vascular cambium region and completely 

surrounds the vascular segments ("steles") of the 

stem. The zone of secondary phloem shows 

anatomical differences between the innermost 

phloem cells (presumably functional phloem) and 

the cells at the periphery of the zone 

(non-functional phloem). Groups of crushed cells, 

including some fibers, are present just outside 

the secondary phloem and may represdnt the 

rermants of primary phloemr. Secondary phloem 

consists of groups of alternating tangential bands 

of fibers, sieve elements and axial (phloem) 

parenchyma, separated by phloem rays. Rays vary 

in height, but are generally high, and average 5-6 

cells in width. The rays are dilated toward the 

periphery of the phloem tissue. Sieve elements 

are extremely long, thin-walled, and exhibit 

crowded sieve areas on the radial walls. Sieve 

areas are oval, approximately 8 x 28 um with 

numerous sieve pores, and some appear to show 

signs of callose deposition. The phloem anatomy 

of Medullosa is quite similar to that described 

for Callistophyton, and can be compared with other 

Carboniferous seed ferns. Phloem anatomy in 

several Pennsylvanian age plant groups is briefly 

summnarized, and possible trends of specialization 

in phloem tissue are discussed. 

STARK, DIXIE SUE PATTEN. Department of Botany, 

University of Montana, Missoula, MT 59812. 

- A new species of pinaceous cones from the 

Tertiary of Maryland. 

Description of a new Pityostrobus species is based 

on a single specimen from an exposure of the Miocene 

Calvert Formation on Chesapeake Bay in Calvert 

County, Maryland. The cone is barrel-shaped, 6.8 cm 

long, and 4.0 cm in diameter. Numerous ovuliferous 

scales are spirally arranged around the central axis. 

They are approximately 2 cm long and 1 cm wide. The 

inflated scale apices and the pattern of vascular 

trace divergence into the bracts and scales are con- 

sistent with the genus Pinus, but the thin, frequent- 

ly-dissected vascular cylinder is atypical. The 

combined presence of features of other Recent genera 

such as Cedrus and Abies dictates assignment of the 

fossil to the genus Pityostrobus. Comparison of the 

specimen with 19 known species of Pityostrobus indi- 

cates that it represents a new species. The struc- 

ture of the cone is inconsistent with the Miocene 

age of the Calvert Formation and it is likely that 

the fossil was reworked from older sediments. 

STEIN, WILLIAM E.* and CHARLES B. BECK. Museum of 

Paleontology, University 

MI 48109. - Triloboxylon 

of Michigan, Ann Arbor, 

(Aneurophyton hallii 

Arnold) arnoldii Matten from the Middle Devonian 

of New York. 

Although several aneurophytalean taxa with threeribbed 

steles have been proposed, clear and consistent 

anatomical distinctions between them have yet to be 

determined. Reasons for this include the fact that 

many new specimens show significant variability in the 

co-occurrence of defining features, and that type 

specimens are often among the most poorly understood 

specimens. As part of a comprehensive analysis of 

large axes attributed to the genus Triloboxylon from 

marine sediments in western New York, we have restudied 

type material of the poorly known T. arnoldii. 

The main axis consists of primary xylem surrounded by 


very extensive secondary tissues. The heterogeneous 

cortex, consisting of parenchyma, fibers, and clusters 

of sclereids, provides evidence of sustained growth 

or secondary modification. At the periphery, bundles 

of fibers are associated with short, dark-filled 

sclereids, and are separated by regular arrays of 

thin-walled cells. There is a possible epidermis 

several cell layers thick. A periderm borders shallow 

fissures in the axis interpreted to be of biological 

origin. Traces, circular in transverse section, are 

borne in subopposite pairs from each primary xylem 

rib. Distally, each trace divides once. Two closely 

related taxa, Reimannia and T. ashlandicum, provide 

different models for what the primary body in 

T. arnoldii might have been like. From these initial 

conditions, different patterns of subsequent develop- 

ment are suggested. Difficulties in interpretation 

persist. If, however, more than one developmental 

sequence could be demonstrated in these forms, then 

we might have a useful key to more natural taxa in 

the group. 

STOCKEY, RUTH. A. Dept. of Botany, Univ. of Alberta, Edmonton, 

Alberta, CANADA T6G 2E9. - Fossil conifers of the northern 

Yukon. Old Crow Basin. 

Large numbers of conifer cones with associated wood have been 

found in alluvial sediments of the Old Crow - Blue Fish Basin in the 

northern Yukon. Early studies of the section known as 12 mile bluff" 

suggest a Late Quaternary age. Recent studies of the bryophytes 

and palynology indicate an older age, possibly Miocene. Three types 

of ovulate pinaceous cones have been identified corresponding to 

the genera Pinus, Picea, and a third small cone representing Tsuga 

section Hesperopeuce or Larix. The relatively unaltered remains 

were removed from a clay matrix, washed, dehydrated and 

embedded in bioplastic or glycol methacrylate for sectioning. 

Cylindrical Picea cones, 7 - 11.2 cm long X 2.1 - 2.8 cm wide, have 

a bluntly rounded base and a slightly acute apex. The 

parenchymatous pith is surrounded by a narrow vascular cylinder 

that is interrLupted between the ovuliferous scale and bract traces. 

Surrounding the vascular cylinder is a parenchymatous cortex 

contaning a ring of conspicuous resin canals. Vascular traces to the 

bract and ovuliferous scale arise separately from the axis stele with 

the resin canal system adaxial to the scale trace. The cones are 

compared to P. banksii Hills & Ogilvie from the Beaufort Fm., P. 

anadyrensis Kryst. from Siberia, and P. diettertiana Miller from the 

Oligocene of Montana. Pinus cones, 7 - 1 0.1 cm long X 1.7 - 2.3 

cm wide, have helically arranged cone-scale complexes each 

bearing 2 ovules. A parenchymatous pith is surrounded by a narrow 

vascular cylinder with few resin canals. Vascular traces arise as a 

single unit. The resin canal system in the scale is abaxial to the 

vasculature. These cones are compared to P. itelminorum Vassk. 

from the Quaternary of Siberia and P. avonensis Miller from the 

Oligocene of Montana. Identification of these remains has added to 

our knowledge of the age of the sediments and provides important 

information with respect to the paleoecology of the basin. 

STROTHER, PAUL K.*, NORMA G. JOHNSON and 

ALFRED TRAVERSE. Department of Geology, 

Dickinson College, Carlisle, PA 17013 and 

Department of Biology, Pennsylvania State 

University, University Park, PA 16802 

-Morphology and phylogeny of Silurian 

spore tetrads. 

Spore tetrads from the Llandoverian (lower 

Silurian) Tuscarora Formation in Pennsyl- 

vania and elsewhere can be placed into three 

morphological categories. Nodospora tetrads 

h-ave two mutually perpendictular axes of sym- 

metry, but the tetrads do not break up into 

individual spores. Tetrahedraletes consists 

of four spores arranged at the apices of a 

tetrahedron which are characterized by thick.- 

ened contact rings. Both Nodospora and Te- 

trahedraletes possibly represent melotic 

products of sporogenesis. Other tetrads are


not characterized by symmetric aggregates of 

spores; they are defined as four spores oc- 

curring within a membraneous sac. Of these 

three configurations only the Tetrahedrale- 

tes-type is strictly morphologically analo- 

gous to embryophyte sporogenous tetrads. 

Our studies suggest that Tetrahedraletes is 

a probable derivative of plants which,were 

ancestral to the spore-bearing embryophytes. 

STROTHER, PAUL K.* and CECILIA LENK. 

Department of Geology, Dickinson College, 

Carlisle, PA 17013-Eohostimella is not a 

plant. 

A detailed palynological investigation of 

the matrix surrounding Eohostimella heath- 

iana (Schopf) revealed an allocthtonous 

assemblage of organic fragments of mixed 

origin. This presumedly upright axial Sil- 

urian plant (Llandoverian C3 to C5 age) oc- 

curs in the Frenchville Formation which is 

considered to be part of a proximal turbi- 

dite sequence. Based on our palynological 

findings, the general geology, the paleo- 

ecology of immediately conformable beds and 

the morphology of the fossil, we conclude 

that Eohostimella is probably a worm tube 

and not a plant. 

* 

STUBBIEFIEID, SARA P. AND THOMAS N. TAYLOR. 

Department of Botany, The Ohio State 

University, Columbus, OH 43210. - Host-path- 

ogen interaction in an Upper Carboniferous 

gymnosperm. 

Evidence of a pathological relationship in the 

gymnospermous pollen cone Lasiostrobus polysacci 

is discussed. Specimens are preserved by 

calcareous cellular permineralization, and were 

collected at the well known Berryville coal ball 

locality (Upper Pennsylvanian). Broad regions of 

cortical parenchyma in the axis of the cone show 

evidence of fungal invasion including disruption 

of host tissues, branching septate hyphae, and 

spherical bodies. Cortical cells often contain 

smaller spheres which sometimes appear spore-like 

in transmitted light. When viewed with scanning 

electron microscopy these spheres consist of 

bubble-like projections from the inner surfaces of 

the host cell walls. They are globular to 

elongate, and may occur singly or in large groups. 

Such structures resemble the callosities often 

formed in response to fungal invasion in a number 

of extant plants, and may stop or retard mycelial 

penetration. It is difficult to determine the 

time of fungal invasion when dealing with 

fossilized organisms. Consequently, the present 

material is particularly interesting since it 

provides evidence of a host response. 

TAYLOR, THOMAS N. * AND KENNETH L. ALVIN. 

Department of Botany, mTe Ohio State University, 

Columbus, OH 43210 and Depertment of Pure and 

Applied Biology, Imp~erial College of Science and 

Technology, London, England. - The ultrastructure 

of Classopollis pollen. 

One of the monst unusual pollen types in Mesozoic 

sediments is the genus Classopollis. This broadly 

defined taxon ranges frcm the late Triassic into 

the Cretaceous (Turonian), and includes spherical 

grains with a sub-equatorial rimula. On the 

proximal pole is a trilete mark, and on the distal 

surface a thin area in the sporoderm termed the 

cryptopore. Ultrastructural studies of 

Classopollis have been completed on grains extract- 

ed from the pollen cone Classostrobus comptonensis 

collected from the upper Wealden of the Isle of 

Wight, England. The mature nexine is composed of 

approximately 20 electron-dense lamellae, each 

about 10 nm thick. The sexine component of the 

sporoderm consists of four (S1 4) easily recog- 

nizable layers, with the most prcminent zone formed 

of coarse, inwardly-tapering elements. The S 

layer is uniformly thickened throtughout the waA, 

except in specialized areas (e.g., trilete, rimula, 

cryptopore) where it thins. The remaining wall 

layers include the spinules that ornament the 

surface and a uniform series of small spaces 

associated with the spinule bases. Grains extract- 

ed from less mature pollen cones provide an oppor- 

tunity to trace some developmental stages in 

Classopollis sporoderm ontogeny, and to compare 

these stages with those of selected extant 

gymnosperm pollen types. 

Taylor, Thomas N.,* Edith L. Smoot and T. 

Delevoryas, Department of Botany, The Ohio 

State University, Columbus, OH 43210 and 

Department of Botany, The University of Texas, 

Austin, TX 78712. - Structurally preserved 

plants from Antarctica: A Triassic cycad stem. 

Vegetative remains assignable to the Cycadales are 

described from the Fremouw Formation (Triassic) of 

the Transantarctic Mountains. Specimens consist 

of well-preserved stem segments approximately 5 cm 

in diameter and associated petioles. In 

transverse section, the vascular cylinder consists 

of endarch primary bundles and radial files of 

small, presumably secondary tracheids with 

scalariform pits. The large, parenchymatous pith 

region is continuous with the cortical parenchyma, 

and contains numerous mucilage cells. Some phloem 

is preserved and there are regions in the stem 

where periderm is conspicuous. Traces to the 

petioles arise in a helical pattern and some 

assume a characteristic girdle configuration in 

the cortex. The presence of many small roots 

with diarch primary xylem suggests that the 

specimens may represent basal regions of the 

plant. The plants from Antarctica are compared to 

other anatomically preserved cycad stems of 

Mesozoic and Tertiary age (e.g., Menucoa, 

Fascivarioxylon, Michelilloa, Lyssoxylon) as well 

as with several extant cycads. 

TIDWELL, WILLIAM D.*, ROSS E. JONES, AND LEE 

PARKER. Department of Botany and Range Science, 

Brigham Young University, Provo, UT 84602, 

Brightwater Road, Blackmans Bay, Tasmania 7152, 

Australia, and Biological Science Department, 

California Polytechnic State University, San Luis 

Obispo, CA 93407. - A new species of Cibotiocaulis 

from Tasmania, Australia. 

A petrified tree fern stem representing a new species 

of Cibotiocaulis was collected from the same locality 

in Tasmania as Cibotium tasmanense which was described 

by Gould (1972). The petrified specimens of

Cibotiocaulis are 11 cm. in diameter and consist of 

a stele surrounded by leaf traces and roots. The 

pith region is filled with numerous medullary bundles, 

the structure of the meristelic margins at the leaf 

gap and the mode of the parting of the leaf-traces 

are somewhat similar to those of living Cibotium 

barometz. The formation of the leaf trace is by 

gradual bulging outward of the stelar ring which 

broadens in its outer portion into a somewhat omega 

shape. The trace remains intact rather than dividing 

into a series of bundles as in the Upper Jurassic 

Cibotiocaulis tateiwae Ogura from Korea. The con- 

figuration of the traces in the petiolar bases of the 

Tasmanian specimens also differs from those in C. 

tateiwae. The traces of the Tasmanian specimens 

are similar to those in the Dicksoniaceae, whereas 

traces of C. tateiwae are more cyatheacean. Numer- 

ous root traces occur, but only outside-of the stele 

in the cortical region. These specimens will be com- 

pared to living members of the Dicksoniaceae and 

Cyatheaceae and to the fossil genus Cyathocaulis. 

TRIVETT, M.L.V.C. Department of Botany, Ohio 

University, Athens, Ohio 45701 - Pollen cones of 

a mesarch cordaitean from the Upper Pennsylvanian 

of the Appalachian Basin. 

Mesoxylon stems of the Mesoxylopsis-type bear leaves 

assignable to Cordaites felicis and a new species of 

Gothania pollen cones that are attached as axillary 

branches. Pollen sacs contain prepollen assignable 

to Sullisaccites Millay and Taylor, and establish 

the natural affinities of this sporae dispersae 

genus. The cones occur either singly, or as one of 

a pair of branches. In the latter case, the other 

branch is a vegetative bud. Cones consist of bi- 

laterally symmetrical primary axes bearing numerous 

four-ranked bracts in the axils of which are fertile 

secondary shoots. The secondary axes have up to 25 

helically-arranged vegetative and fertile scales. 

Fertile scales are confined to the apical region and 

terminate in four elongate pollen sacs that are ar- 

ranged in a linear fashion. In immature specimens, 

the vegetative scales are tightly imbricate, com- 

pletely enclosing the fertile tip. However, the 

pollen sacs of mature specimens extend well beyond 

the vegetative zone, and appear as large masses on 

coal-ball surfaces. This is the second cordaitean 

to be characterized from the Steubenville assemblage, 

and it demonstrates that the entire plant can not be 

recognized from single or isolated vegetative organs. 

Upchurch, G.R. Division of Paleobotany, W-312 

MNH, Smithsonian Institution, W4ashington, D.C. 

20560 - Ficophyllum leaves from the Lower 

Cretaceous Potomac Group:. Evidence for possible 

affinities with Magnoliales and Austrobaileyaceae. 

Reinvestigation of upper Zone I (Aptian?) angiosperm 

leaves belonging to the genus Ficophyllum corrorborates 

previous ideas on possible affinities to Magnoliales, 

but also shows the presence of many features typical 

of Austrobaileyaceae. These leaves are large and have 

a midrib comprised of numerous anastamosing strands, 

as in certain primitive Magnoliales. Their irregular 

pattern of festooned brochidodromous 20 venation is 

suggestive of Winteraceae, but the basal 20 veins are 

oriented at a lower angle than the others in a manner 

characteristic of Austrobaileyaceae and other Laurales. 

The 30 venation is random reticulate, as in many 

Magnoliales, and its higher order venation has a 

suite of features most suggestive of Magnoliaceae 

and Austrobaileyaceae. The 40 and 50 veins are retic- 


ulate, with a tendency towards orthogonal rooting, 

and are thin for a leaf of large size. The areolation 

tends towards 4-sided and in some regions the areoles 

are elongate at right angles to the midrib. Freely 

ending veinlets generally are unbranched and occur in 

less than 50% of the areoles. The higher order vena- 

tion of Magnoliaceae differs from that of the fossil 

only by its more numerous and more branched freely 

ending veinlets, while that of Austrobaileyaceae 

lacks 50 veins and has larger, more elongate areoles. 

Stomatal features are preserved on some cuticles and 

the suite of characters is most similar to that of 

Austrobaileyaceae. According to many neobotanical 

systems of classification this leaf would represent a 

very primitive angiosperm. However, its occurrence 

with angiosperm leaves that possess only 3 well-devel- 

oped orders of venation suggests that Ficophyllum may 

be more advanced than some Zone I forms. 

Upchurch, G.R. Division of Paleobotany, W-312 

MNH, Smithsonian Institution, Washington, D.C. 

20560 - The cuticular anatomy of "platanoid" 

leaves from the Lower Cretaceous Potomac Group. 

Studies of Cretaceous angiosperm leaf architecture 

have provided evidence for a group of leaves with 

affinities to Platanaceae known as the "platanoids". 

Additional evidence comes from the cuticular anatomy 

of platanoid leaves from upper Subzone II-B ( or 

Albian) of the Potomac Group. In every species the 

stomatal complex ranges from paracytic to laterocytic 

and weakly cyclgcytic. Some of the subsidiary cells 

form from the 2 division of neighboring cells. 

Platanaceae are similar except that they lack paracy- 

tic stomata and all of their subsidiary cells arise 

through 20 divisions. In addition, the fossil leaves 

possess hair bases identical to those in extant 

Platanus or hair bases and secretorv cells that ap- 

pear to be homologous. In Platanoid #1 there are se- 

cretorv cells and hair bases that intergrade with 

them. The secretory cells range from dome-shaped to 

bulbous and are variably positioned with respect to 

the adjacent cells. The hair bases have foot cells 

that are identical to some secretory cells except that 

each bears an apical hair abscission scar. In 

Platanoid #2 there are onlv dome-shaped secretory 

cells, which unlike those in Platanoid #1 are always 

positioned over the junction of two or more cells. In 

Platanoid #3 there are only hair bases of the Platanus 

type, which resemble those of Platanoid #1 but are 

always positioned over the junction of two or more 

cells. Identical hair bases occur on an associated 

inflorescence that consists of an axis bearing heads, 

as in some Platanaceae. Hence, the cuticular anatomy 

of Potomac Group platanoids, along with the closer 

resemblances shown by Late Cretaceous platanoid cu- 

ticles with modern Platanaceae, suDport the concept 

that the Potomac Group platanoids belong to the com- 

plex from which extant Platanaceae are derived. 

Upchurch, G.R.*, L.J. Hickey, and K.J. Niklas. 

Division of Paleobotany, W-312 MNH, Smithsonian 

Institution, Washington, D.C. 20560, Peabody 

Museum, Yale University, New Haven, CT 06520, 

and 214 Plant Sciences Building, Cornell Universi- 

ty, Ithaca, NY 14853 - Leaves with chloranthoid 

characters from the Lower Cretaceous Potomac 

Group. 

Studies of leaf remains from Zone I (Aptian?) of the 

Potomac Group of Virginia reinforce palynological ev- 

idence for the chloranthaceous affinities of a group


of Early Cretaceous angiosperms. Several species bf 

serrate leaves possess Chloranthoid teeth with promi- 

nent glands in which the lateral veins run parallel 

to the margin and fuse with the gland. Similar teeth 

occur in some Chloranthaceae, Amborellaceae, and 

Tetracentraceae. One fossil species shows additional 

chloranthoid characters in its higher order venation, 

cuticular anatomy, and chemistry. Its areolation is 

elongate, with few freely ending veinlets, as in some 

species of Ascarina. Its suite of cuticular features 

is found only in Chloranthaceae, but individual char- 

acters occur in other families as well. The paleobio- 

chemistry of the cuticular remains is most consistent 

with as assignment to Chloranthaceae. However, the 

species differs from modern Chloranthaceae in its 

simple craspedodromous secondary venation, its rudi- 

mentary quaternary venation, and its alternate leaf 

arrangement. The latter two characters suggest that 

this leaf group is more primitive than modern 

Chloranthaceae and that the family may not have orig- 

inated until later in the Cretaceous. 

WARD, JEROME V. Department of Botany and 

Microbiology, Arizona State University, 

Tempe, AZ 85287 

-Hexarugate pollen from the Albian of 

Kansas. 

A study of the terrestrial palynoflora from 

outcrop localities (including the types) of 

the Cheyenne and Kiowa formations of Kansas 

was undertaken to assess the range of varia- 

tion of early angiosperm pollen, species 

composition, and to compare with coeval pal- 

ynofloras. One discovery is the occurrence 

of dicotyledonous pollen with hexarugate 

morphology, i.e., six non-equatorial aper- 

tures aligned in a tetrahedral fashion. These 

hexarugate pollen types are regarded as vari- 

ants of the normally occurring tricolp(-or, 

-oroid)ate pollen species recognized as 21 

informal morphotypes accommodated in 19 form 

species. This approach to classification has 

implications for strict typological taxa, 

where observance of modern pollen variation 

in relation to the fossil realm can lead to 

more natural paleotaxonomic groups. 

Hexarugate pollen, most common in modern 

Caryophyllales, complies with Van Campo's 

(1976) model of "successiformy" and provides 

a link between triaperturates and pericolpate 

grain types. Whereas the relative adaptive 

advantage of this morphotype may be argued 

(e.g., greater germination efficiency), it is 

probable that it is a product of selective 

pressures, in part operating within the di- 

versity of mid-Cretaceous pollinating sys- 

tems. 

WIGHT, DAVID C.* and CHARLES B. BECK. Division of 

Biological 


Sciences and Museum of Paleontology, 

of Michigan, Ann Arbor, MI 48109. - 

Aneurophytalean progymnosperms from the Millboro 

Shale of southwestern Virginia. 

A significant portion of a large suite of permineralized 

axis fragments collected from the Purcell Member 

of the Millboro Shale (probably upper Eifelian) 

is assignable to the order Aneurophytales (Progymnospernopsida). 

Although these specimens are among the 

oldest structurally preserved members of this order, 

some show great similarity to other members of the 

order which occur somewhat later in time. One such 

specimen consists of three orders of branching. 

Primary xylem of first and second order axes is pro- 

tostelic and deeply three-ribbed. Order of matu- 

ration of primary xylem is mesarch with several pro- 

toxylem strands present in each rib. Traces to 

second order axes are produced helically. A subop- 

posite pair of ultimate appendage traces is produced 

concurrently with the production of traces to second 

order axes. Primary xylem of the ultimate appendages 

is circular in outline with a single central proto- 

xylem strand. Secondary xylem is present in both 

first and second order axes. This specimen shares 

characters with the Middle Devonian taxa Reimannia 

aldenense Arnold and Cairoa lamanekii Matten, and the 

Middle to Upper Devonian Triloboxylon ashlandicum 

Matten and Banks. Preservation is sufficiently good 

to permit the precise determination of -the distri- 

bution of protoxylem strands in the primary xylem and 

their association with trace departure in this and 

other specimens. The patterns present are consistent 

with the view that aneurophytalean progymnosperms 

were derived from some trimerophyte-lik' form. 

WINSTON, RICHARD B. Department of Geology, 

University of Illinois, Urbana, IL 61801. 

- A Late Pennsylvania extrabasinal flora and its 

environment. 

The Late Pennsylvanian (latest Missourian) flora of 

the Rock Lake Shale Member of the Stanton Limestone 

Formation was restudied in depositional succession as 

part of a broader biological and ecological study of 

a site at Garnett, Kansas, Twenty species of mega- 

fossils were found including five species of ovules). 

The megaflora is dominated by Lebachia garnettensis 

with Cordaites being subdominanto Morphological and 

comparative evidence supports the conclusion that 

L. garnettensis abscissed its ultimate branches. 

Callipteris flabellifera is common but not abundant. 

The remaining vegetative species are rare. Nearly 

all the fossils collected were gymnosperms. 

Cordaites is most abundant in the uppermost 40 cm of 

the unweathered portion of the 150 cm thick deposit, 

especially the top 20 cm. The microflora was 

dominated by Potonieisporites pollen from the 

pollen cones of'Lebachia'gatiettensis. The miospores 

which show the most distinct clhanges in r_lattve 

abundance are Protohaploxypinus and Vesicaspora. 

Protohaploxypinus was common in the lower portion of 

the deposit but was, to a large extent, replaced by 

Vesicaspora near the top of the deposit. These 

changes, together with the increase in relative 

abundance and cover of Cordaites near the top of the 

deposit suggest that the local environment was 

slightly moister when the upper part of the shale was 

deposited, but that the conditions were generally 

mesic througout the interval of deposition. The 

following taxonomic changes have been made: emenda 

tion of the description of Lebachia garnettensis 

and reduction of Dichophyllum moorei to a subspecies 

of Callipteris flabellifera. 

WINSTON, RICHARD B. Department of Geology, 

University of Illinois, Urbana, IL 61801. 

- Systematics of the primitive conifer Lebachia. 

A cladistic analysis of the genus-Lebachia has been 

performed. The probable relations of Lebachia to 

other groups is reviewed. The genus Walchia semsu 

stricto (Ernestiodendron) is considered to be derived 

from'Lehachia. The Cordaitales and Lebachia are 

considered to be sister groups and hoth are consider-

ed to be derived from Archaeopteris or some similar 

progymnosperm. These relationships are useful in 

determining polarities in some characters but such 

characters could not be polarized by reference to an 

outgroup. The polarized characters were used to 

choose the best point at which to root a Wagner 

network constructed with the unpolarized characters. 

The resulting phylogeny was used to predict the 

character states in certain species in which these 

data have not so far been obtained. Two natural 

groups were distinguished in Lebachia. One group 

had ovuliferous cones borne at the tips of its 

penultimate branches while the other had ovuliferous 

cones borne at the tips of ultimate branches. The 

former group contained some members with flattened 

short shoots in their ovuliferous cones and appears 

to be ancestral to Walchia sensu stricto. 


PHYSIOLOGICAL SECTION 

HABERMANN*, HELEN M. & ELSIE W. SHOEMAKER. Dept. of 

Biological Sci., Goucher College, Towson, MD 21204 

-Does barometric pressure affect stomatal opening? 

Stomata vary in their response to light even when the 

biological and environmental factors known to affect 

opening are controlled. Such factors include leaf 

position and plant age, temperature, light intensity, 

relative humidity, C02, adequacy of mineral nutrients 

and water. A possible cause for the variability of 

stomatal response is fluctuation in barometric pressure 

(BP), an environmental factor that, according to 

Gale (Isr.J.Bot. 20: 334), can affect transpiration. 

Our studies tested for effects of ambient BP (at time 

of sampling and for 24 h before) on stomatal aperture 

& guard cell potassium level (K, % stain) in Helianthus 

annuus. Plants grown hydroponically in a greenhouse 

were sampled (4/30 to 6/3/82) after forming 17 

to 25 leaves longer than 1 cm. Before testing, plants 

were transferred to a growth chamber (300C & 80% RH) 

with the same 14/10 h day/night cycle as the greenhouse. 

At 9:30 EST the next morning stomatal apertures 

were determined by means of silicone replicas & 

guard cell K was estimated (using the standards of 

Fischer: Aust. J. Biol. Sci. 25: 1107) in epidermal 

strips stained with Na cobaltinitrite. For each plant 

3 or 4 young, fully expanded leaves with maximally 

responsive stomata (generally 5th to 10th leaves) 

were assayed. BP was monitored with a Taylor recording 

barometer. With "low" ambient BP at sampling 

time (below 29.78 in Hg = 100.84 kPa) mean stomatal 

aperture was 7.62 ? 1.65 uim and guard cell K was 

22.83 + 12.25 (N = 11 plants). At "high" BP (29.78 

in Hg & above) aperture was 3.35 ? 2.85,um and K was 

12.85 ? 7.58 (N = 17 plants). Eight of the "high" BP 

plants had open stomata. All 9 "high" BP plants with 

closed stomata (mean aperture of 0.82 ? 0.56 ,um and K 

of 8.41 +. 1.00) had been subject to increases in BP 

during the 4 to 12 hours prior to sampling. 

Physiological Section 83 

ZAVADA, MICHAEL S. Department of Biology 

Indiana University, Bloomington, IN 47405 

The origin of self-incompatibility 

in angiosperms: A paleobotanical per- 

spective. 

The functional significance of the pollen 

exine is discussed with special reference 

to intraspecific incompatibility in angio- 

sperms. There is a correlation between 

tectate-columellate-perforate(reticulate) 

pollen walls and sporophytic self-incomp- 

atibility. Other pollen wall types are 

discussed in relation to gametophytic self- 

incompatibility. The evolutionary trends 

based on neontological data for self- 

incompatibility and wall structure in 

angiosperms are considered. The signifi- 

cance of these data for interpreting the 

earliest fossil dispersed angiosperm 

pollen and the role that self-incompatibil- 

ity may have played in the oirigin and 

early evolution of angiosperms is dis- 

cussed. 

MAJUMDAR*, SHYAMAL K., and STUART A. 

SANDLER. Department of Biology, Lafayette 

College, Easton, Pennsylvania 18042. 

-Totipotency of Episcia cupreata roots 

grown in vitro. 

Roots derived from the green callus of 

Episcia cupreata "pink brocade" were 

investigated for their totipotency poten- 

tial. The roots were cultured. on Murashige- 

Skoog medium with and without the hormones 

N6-benzyladenine (BA) ando4-naphathaleacetic 

acid (NAA). Callusing occurred within three 

to six weeks on both media. The calli 

clumps developed along the root's length, 

and it appeared light to dark brown in 

color. Differentiation of the callus to 

plantlets with leaves and roots occurred 

within an additional three to five weeks on 

the medium without the BA and NAA. Occasion- 

ally, albino plants were found to develop on 

this medium; however they remained small and 

did not produce any root system. On medium 

with BA and NAA the roots continued to 

produce calli with no noticeable rediffer- 

entiation until after ten to twelve weeks of 

callus formation; however the plants lacked 

roots. The findings are of importance in 

that they demonstrated totipotency of in 

vitro grown Episcia cupreata roots in the 

absence of BA and NAA hormones. The roots 

were able to produce callus, and the callus 

tissue in turn was found to differentiate 

into plantlets with leaves and roots. 

SASAKI, KEN AND TAYLOR, IAIN E. P. Department of 

Botany, University of British Columbia, Vancouver, 

B.C., V6T 2B1, Canada. 

- Myo-inositol in cell wall synthesis during 

germination of Phaseolus vulgaris L. 

Imbibition by total submersion caused considerable 

seed damage as well as reduced germination and

84 Physiological Section 

seedling growth. Imbibition on moistened cotton in 

a small sample bottle eliminated the damage, allowed 

rapid germination and seedling growth and resulted in 

substantial isotope uptake fo5 

metabolic studies. 

P. vulgaris seeds were fed 2- H myo-inositol (MI) by 

imbibition. The largest amount of MI was imbibed 

from 500mM MI (14-17 pmoles/seed) and She highest 

percentage was imbibed at lmM (30% of H given). 3 

During germination and growth in vermiculite, more H 

appeared in hypocotyl than in roots at all concen- 

trations provided. Half of the label was in the 80% 

insoluble materials and more than 85% of it was 

released by hydrolysis with 2N trifluoroacetic acid. 

The youngest part (0-2 cm below cotyledons) of the 

hypocotyls in 4- and 6-day old seedlings contained 

larger amounts of the label than did parts 2-6 cm 

from the cotyledons. However, most of the label was 

in the oldest part of the hypocotyls (more than 6 cm 

from cotyledons). These results show that exogenous 

MI is used in polysaccharide synthesis of very young 

tissue and in older tissue that has completed its 

extension phase. 

(Supported by NSERC of Canada). 


ALLEN* RANDY D. AND HOWARD J. ARNOTT 

Department of Biology, Texas A&M Univer- 

sity, College Station, TX 77843. Depart- 

ment of Biology, University of Texas at 

Arlington, Arlington, TX 76019. - Effects 

of metabolic inhibitors and growth regu- 

lators on storage protein mobilization in 

sunflower cotyledons. 

Scanning electron microscopy was used to ob- 

serve protein body digestion in cotyledon 

cells of Helianthus annuus L. Digestion oc- 

curs in three distinct stages: 1) Internal 

erosion of separate protein bodies. 2) Fusion 

of protein bodies to form larger protein vac- 

uoles. 3) Gradual digestion and removal of 

storage protein from the vacuole to form a 

main cell vacuole. Germination of seeds in 

solutions of cycloheximide, a translation 

inhibitor, or actinomycin -D, which inhibits 

transcription, indicates that internal pro- 

tein body erosion occurs in the absence of 

both RNA and protein synthesis. Protein 

body fusion appears to require protein syn- 

thesis but is independant of RNA synthesis. 

The final and most extensive phase of pro- 

tein hydrolysis requires both RNA and protein 

synthesis for development. Digestion of pro- 

tein vacuole contents is also inhibited in 

cells of cotyledons excised from the embry- 

onic axis. Addition of embryonic axes or 

exogenously supplied cytokinin to excised 

cotyledons stimulates storage protein diges- 

tion. Addition of gibberrellic acid or 

indole acetic acid to excised cotyledons 

does not replace the influence of the embry- 

onic axis. High concentrations of indole 

acetic acid may actually inhibit protein 

body erosion and fusion. 

ALLEN, RANDY D. and CRAIG L. NESSLER. * Department 

of BSiology, Texas A&M University, College Station, 

TX 77843 -Pectinase activity in the nonarticulated 

laticif ers of Nerium oleander and its role 

in intrusive growth. 

Pectinase activity was localized in the nonarticulated, 

branched laticifers of Nerium oleander at the 

ultrastructural level using a newly developed cyto- 

chemical localization technique. The procedure 

involves the use of Benedict's reagent to form an 

electron opaque reaction product when exposed to the 

reducing sugars liberated from exogenously supplied 

pectin. Electron opaque crystalline deposits, 

indicating the presence of pectolytic enzymes, were 

identified in the large central vacuole of oleander 

laticifers. Smaller amounts of reaction product 

were observed scattered along the middle lamella 

between laticifers and adjacent parenchyma cells. 

In control tissues, boiled prior to pectinase 

incubation or which were not incubated in pectin, 

deposits were found only in the middle lamella and 

not in the vacuole. Growth of the nonarticulated 

laticifer system in oleander is accomplished through 

intrusive growth between adjacent nonlaticiferous 

cells. The present report on the distribution of 

pectinase activity in oleander laticifers suggest 

that this enzyme is responsible for dissolving the 

middle lamella ahead of the growing laticifer tip. 

AMIRO*, BRIAN D., TERRY J. GILLESPIE, AND GEORGE W. 

THURTELL. Dept. of Land Resource Science, 

University of Guelph, Guelph, Ontario. NlG 2W1. 

- Injury response to ozone flux density in 

Phaseolus vulgaris L. 

A quantitative relationship between ozone mean flux 

density and the length of exposure needed for the 

occurrance of visual foliar injury to Phaseolus 

vulgaris L. is described. Similar relationships 

were found for 14 day old and 6 week old plants 

using a whole leaf gas exchange cuvette system. 

Cultivars Seafarer (ozone sensitive) and Gold Crop 

(ozone resistant) exhibited similar responses at 

flux densities > 3 mg m72h-1 but only Seafarer 

was injured below this threshold. Ambient ozone 

concentration and length of exposure period alone 

do not contain sufficient information to predict 

the onset of visual injury. 

AMIRO*, BRIAN D., GEORGE W. THURTELL, and TERRY J. 

GILLESPIE. Dept. of Land Resource Science, 

University of Guelph, Guelph, Ontario. NIG 2W1. 

- A small infrared thermometer for measuring 

leaf temperature in leaf chambers. 

A small, inexpensive infrared thermometer is des- 

cribed. This instrument is easily used and is more 

accurate than thermocouples for leaf temperature 

measurements. This thermometer can be used to make 

leaf temperature measurements with estimated errors 

of less than 0.2 C when used in a typical leaf 

chamber. 

B4JAJ, Y.P.S. and SS.GOSAL, Tissu.e Cuture 

Laboratory, Panjab Agricultural University, 

Ludhiana, India. 

Somatic hybridiza3tion and emnbryo culture 

studies on Arachis rpoe x Arachis villosa. 

Protoplast fusion and embryo cult?e stdies have 

been coriduocte& onx an i.ncom:patible cros~s involving a 

cultivrated tetraploid pearnut (A,hi hXZ2?sea 

4x40) anld a wild diploici species Arachis vi11osa 

(whicha ha? higher oil contents and is drough an 

diBea.se resis~tant). She hybrid embr!yos which 

generally abort in natuxe, were re~csed 30-35 days 

after pollination anid successfu~lly cutut~red. on

synthetic media. The hybrid plants showed t:riploid 

chromosome nuber (3X=30). 

Por somatic hybridization, a comparison of veaicxs 

segments of the in vitro-grown seedlings of AhuoE 

was made, and. the optimal yield of protoplastc (1 .5x 

105/g) was obtained from the excised bypocotyl 

segnents of 10-14 day-old seedlings, t;reated with an 

enzsyme mixture of cellulase (1.5), macerozyme (1%o), 

CaCd2 (0.3%) in mannitol at pH 5.6 inctibated for 

12-15 hrs. Of the two species, A. e was more 

amenable to various treataents. The mesd6pyll proto- 

plasts from A. ea, were ftused with callus- 

derived protoplasts of A. villosa. Treatment with 

20-25% polyethylene glycol resilted in 11-13% Thion 

products. The genetic variables obtained as a result 

of variou in vitro manipulations will be incorpo- 

rated into peanut improvement programs. 

BIESBOER, DAVID D. Department of Botany, 

University of Minnesota, St. Paul, MN 55108. 

-Nitrogen fixation associated with natural and 

cultivated stands of Typha latifolia. 

Acetylene reduction by bacteria associated with l)pha 

latifolia L. roots and rhizomes was studied in the 

laboratory and in the field. In situ studies indicated 

that the rate of acetylene reduction in a natural cattail 

population was 3-fold higher than in a cultivated stand. 

Scanning electron microscopy and 2, 3, 5 

triphenyltetrazolium chloride reduction showed that the 

bacterial rhizocoenosis was limited to the rhizoplane of 

roots and rhizomes. Seasonal changes in dinitrogen 

fixation, numbers of associated dinitrogen fixing 

organisms, and rhizome/root carbohydrates were also 

studied. Anaerobic dinitrogen fixing bacteria 

predominate in this association and show a close 

correlation between total acetylene reduction and 

population numbers during the growing season. Maximum 

nitrogen fixation coincides with reproductive development 

in ?\pha with peak acetylene reduction occurring at the 

time of fruit and seed development. Root sugar 

concentrations reach a maximum approximately two 

weeks prior to peak acetylene reduction suggesting that 

increased production of root exudates precedes an 

increase in total dinitrogen fixation by the associated 

microflora. 

CHEN, CHEN-HO*, WENDY L. JONES, and DAVID D. 

SONGSTAD. Department of Biology, South Dakota 

State University, Brookings, SD 57007 - Cloning 

Lilium formosanum through leaf and bulbscale 

cultures. 

Young leaves stripped from floral stalks and sections 

of scales, 2-3 mm thick, removed from cool-treated 

bulbs (100C for 4 weeks), were explanted on Murashige 

and Skoog's (MS) medium supplemented with 0, 0.03, 

0.3, or 3 mg kinetin in combination with 0, 0.1, or 1 

mg naphthaleneacetic acid (NAA) per liter. All of the 

cultures were incubated in the dark at 250C. In both 

experiments adventitious buds, and roots in some 

treatments, initiated directly from explants in 4 to 5 

weeks after explanting. Kinetin tended to promote bud 

formation but retard root initiation. NAA did the 

reverse. Unlike those of L. longiflorum, which transformed 

to bulblets and became dormant, the buds in L. 

formosanum cultures continued to grow and develop into 

independent plantlets after transferred onto MS medium 

devoid of hormones and incubated at 25 - 300C under 

16-hr photoperiodic cycles (cool-white fluorescent 

light at 2 klx). The plants flowered two years after 

t ransplanted in the soil . 


ELLIS, D. E.* and D. E. BILDERBACK. Department of 

Botany, University of Montana, Missoula, MT 59812. 

- Multiple bud formation of Larix occidentalis in 

sterile tissue culture. 

The timber industry of the Pacific Northwest has been 

interested in discovering new methods of propagating 

Larix vegetatively. Multiple buds have been induced 

on 7-10 day old seedlings in sterile tissue culture 

but, like stem cuttings, roots are still an obstacle 

to reliable plantlet formation. Following hydration, 

seeds require a minimum of 15 days of cold stratifi- 

cation before germination is achieved and before buds 

can be induced in tissue culture. Seedlings are sur- 

face sterilized in 4% Clorox and placed on the medium 

of Reilly and Washer (1977), supplemented with var- 

ious concentrations of benzyladenine (BA). Buds form 

from the epicotyl region after 6-8 weeks in culture. 

Elongation is achieved by excising and transferring 

the buds to the medium of Reilly and Washer without 

the addition of any hormones. Buds grow relatively 

slowly in tissue culture, and problems with sterility 

hindered progress with embryonic tissue due to bac- 

terial contamination on the embryo in the seed. 

ELLIS, D. E.* and D. E. BILDERBACK, Department of 


- The use of sterile tissue culture to induce 

multiple buds on Pinus ponderosa. 

In order to meet the expanding need for genetically 

superior trees, researchers have begun to use sterile 

tissue culture as a means of vegetatively propagating 

conifers. Excised embryos of Pinus ponderosa form 

multiple buds on several nutrient media with varying 

hormone concentrations. Embryos placed on the medium 

of Reilly and Washer (1977) were subjected to differ- 

ent concerntrations of benzyladenine (BA) ranging from 

1 mg/l to 10 mg/l. While all concentrations yielded 

some multiple buds, concentrations below 2.5 mg/l and 

above 7.5 mg/l yielded substantially fewer buds. 

Embryos placed on the medium of Cheng (1975) contain- 

ing 1.02 mg/l 6(y,y-Dimethylallyl-amino)-purine(2iP), 

0.88 mg/l indole acetic acid (IAA), 1.02 mg/l indole 

butyric acid (IBA), and 1.13 mg/l BA produced a 

limited number of buds. By reducing the nutrient, 

vitamin and hormone concentrations of both media by 

one half, embryos formed more buds and formed them 

earlier than on the full strength media. 

GALEWSKY, 

SAMUEL*, and CRAIG L. NESSLER. Depart- 

ment of Biology, Texas A&M University, College 

Station, TX 77843. - In vitro synthesis of phen- 

anthrene alkaloids by somatic embryos of the opium 

poppy, Papaver somniferum. 

Extracts of somatic embryos of the opium poppy, Papa- 

ver somniferum were examined by high performance 

liquid chromatography for the presence of phenan- 

threne alkaloids. The analysis was done by reverse 

phase using a C18 column with a gradient system. The 

solvents were: A - 10 mM perchlorate buffer, pH 4.0, 

with 5 mM N-butylamine; B - acetonitriale. The gra- 

dient was run from 90% to 27% A over 5 minutes and 

isocratic at 27% A, 73% B for an additional2 minutes. 

Phenanthrene alkaloids were positively identified in 

suspension cultures of somatic embryos, but were not 

detected in callus or nonembryonic suspensions. The 

presence of well developed laticifers in somatic 

embryos may account for their ability to synthesize 

phenanthrene alkaloids in vitro.


GALLAGHER, JOHN L.*, DONNA GRANT AND MICHAEL 

SIEGEL. College of Marine Studies, University 

of Delaware, Lewes, DE 19958 

- Effect of perturbations on the underground 

reserves of Carex lyngyei, Spartina 

alterniflora and Distichlis spicata 

Various methods of assessing underground reserves 

have been used to evaluate the condition of perennial 

forage crops, such as alfalfa, when they are in 

the dormant stages. Cultural practices, disease or 

insect pests can cause the plant stands to be 

weakened in subsequent years by having a detrimental 

effect on the reserves the plants store for initial 

growth in the spring. Measurement of such reserves 

following summer growth may be a technique which 

could be exploited in assessing the ecological 

impact of perturbations to the system. The studies 

reported here examine the effects of defoliation, 

nitrogen fertilization and treatment with the 

herbicide amitrol. One defoliation of Spartina 

alterniflora in Georgia reduced the reserves recoverable 

in the fall to zero. Repeated defoliation 

of the Delaware stand did not have as drastic an 

effect nor did similar treatment on Carex lyngbyei 

in Oregon. The herbicide treatment reduced recoverable 

reserves quantity and duration of release 

to aboveground productions. In Oregon Carex 

lyngbyei stand the regrowth material from all 

pertubattions was higher in N, P, K than in the 

control. Defoliation and herbicide treatments 

applied to Delaware Spartina alterniflora reduced 

the quantity of reserves, but did not alter the 

N content but P content was reduced. 

GOVIL ,SUDHA R. ,DC AGRAWAL, KP RAI AND 

SN TIiAKUR. Department of Farm Engg., 

Institute of Agricultural Sciences, 

Banaras Hindu University,Varanasi ,India. 

Ef fect of radiation in UV region on 

green-gram PThaseolus aureusL - An 

experiment wtEFTse. 

The erfect of laser radlation on growth, 

chlorophyll, nucleic acids and protein 

contents in green-gram has been investigated. 

Dry seeds irradiated with pulsed nitrogen 

laser* at 337.1 nm were germinated in Petri 

plates (12 h illumination daily) for a week. 

The variations in the above parameters with 

exposure time are as follows: 

Parameters Irradiation 

0 5 

time (Min.) 

20 40 

Shoot length 

Root length 

Fresh weight 

(mg/plant) 

Dry weight 

(mg/plant) 

Chlorophyll 

(cm) 

(cm) 

16.8 19.4 21.2 

6.6 7.0 8.1 

238.9 292.9 364.0 

19.5 23.0 25.8 

18.8 

6.6 

295.1 

21.8 

(pg/plant) 37.0 31.0 39.0 36.9 

RNA (pg/mg) 

DNA (pg/mg) 

Protein (pg/mg) 

11.5 

0.5 

66.4 

27.1 15.5 8.1 

1.4 0.8 0.4 

90.5 185.6 151.4 

*Characteristics of pulsed nitrogen laser 

Output pulse energy .. 10 3Joule 

Outpult peak power .. 200 KW 

Output energy available .. 0.053 .T/min/seed. 

HAWKINS, JANICE L.* AND JANET R. DUGLE. 

Environmental Research, Whiteshell Nuclear 

Research Establishment, Pinawa, MB, ROE ILO 

-Growth in black ash: influence of gamma radiation 

Various aspects of growth in black ash (Fraxinus nigra 

Marsh.) are being studied in the Field Irradiator - 

Gamma area of eastern M4anitoba. Measurements of 

height, circumference, and diameter have been taken 

twice a year beginning in 1970 and continuing to the 

present. Long-term irradiation at dose rates ranging 

from 62.5 mGy/h to background began in March 1973. 

No ash were surviving at a dose rate greater than 

15.6 mGy/h at the end of the 1982 growing season. 

The largest increase in girth was observed at dose 

rates of 0.88 mGy/h to 1.27 mGy/h. At some dose 

rates radiation increases leaf size. Leaves on 

saplings exposed to 14.9 mGy/h ranged in length from 

91-353 mm (mean 182 mm). Cell size of-these leaves, 

measured with collodion casts, was significantly 

larger than the controls (F=16.5;n=64). Exposure to 

dose rates greater than 0.25 mGy/h reduces the length 

of the growing season by causing later flushing and 

earlier abscission. At some of these dose rates, 

therefore, growth per unit time is considerably 

higher than that of unirradiated ash. 

JENSEN, KEITH F. Forestry Sciences Laboratory, 

359 Main Road, Delaware, Ohio 43015. 

-Impact of ozone on yellow poplar seedlings 

stressed with air pollutants. 

One-year-old yellow poplar (Liriodendron tulipifera 

L.) seedlings were stressed with air pollutants by 

fumigating them with either 0.05 ppm ozone, 0.1 ppm 

SO2, or both 0.05 ppm ozone and 0.1 ppm SO2 for 12 

hours per day 7 days a week. The seedlings were 

then fumigated for 6 hours 1 day a week with 0.2 ppm 

ozone. The treatments lasted for 20 weeks. Eight 

seedlings were harvested from each treatment at 

4 week intervals throughout the study. Growth 

response curves for height, leaf area, leaf weight, 

and total weight were developed and analyses of 

variance were performed on the data. Significant 

differences were found in total weight after 20 weeks 

of treatment. Seedlings predisposed with SO2 or SO2 

plus ozone had significantly less dry weight than 

the controls. The 0.2 ppm ozone fumigation had no 

effect on either the unstressed or pollutant 

stressed plants. 

KARIMI, S. H. and I. A. UNGAR. Department of 

Botany, Ohio University, Athens, Ohio 45701 - 

Effect of aeration, shading and salinity on oxa- 

late accumulation of Atriplex triangularis Willd. 

To investigate the accumulation of oxalate in 

response to conditions present in natural habitats 

of Atriplex triangularis, plants were grown in 

hydroponic solutions at low and high light intensi- 

ties, plus or minus aeration and in salt solutions 

ranging from 0 to 3% NaCl. The highest total oxa- 

late concentration, about 12% of dry weight, was 

found in the leaves of plants grown under high light 

intensity, in well aerated and non-saline media. 

Shading and lack of aeration produced low total oxa- 

late content in leaves. As media salinity increased 

leaf total oxalate was found to decrease. Other 

organs, including stems, fruits and roots, had lower 

concentrations of oxalate than the leaves. Shedding

leaves- contained high quantities of oxalate compared 

to other plant organs. Addition of salt to the 

nutrient media resulted in an increase in the water 

soluble form of oxalate and a decrease in the acid 

soluble form. The significance of these findings in 

relation to the osmotic adjustment of plants and the 

balancing effect of oxalate in the presence of excess 

cations will be discussed. 

KAUSCH, A.P. Department of Botany, Iowa State 

University, Ames, IA 50011. 

- Media modifications affecting oxalate production 

and calcium oxalate crystal cell differentiation 

in Psychotria 

cultures. 

callus and Yucca isolated root 

Callus cultures of Psychotria punctata are initiated 

and maintained on a modified Linsmaier and Skoog 

medium; isolated root cultures are made from primary 

roots of Yucca torreyi seedlings and grown in White's 

medium. Affects of various media additions or 

alterations on culture oxalate production are determined 

as total oxalate content. Oxalate is 

assayed as the butylated ester derivative with gas 

chromatography from freeze-dried samples. Growth 

regulator variations in Latin square analysis for 

callus cultures show no affect on oxalate content for 

NAA/K, IAA/BA, or 2,4-D/BA regimes despite positive 

growth responses to these compounds. Each of the 

growth regulator combinations possess different 

capacities to support crystal cell differentiation. 

Decreasing NH4NO3: KNO3 ratio and increasing ascorbic 

acid concentrations result in elevated oxalate content 

in callus cultures. Ascorbic acid addition to 

Yucca root cultures results in increased oxalate 

content and numbers of crystal idioblasts formed in 

the root cortex. Affects of media addition of 

a-HPMS, lycorine and allopurinal treatments (oxalate 

biosynthesis inhibitors), and pH alterations are 

compared between Psychotria 

cultures. 

callus and Yucca root 

KAUSCH, A.P.* and H.T. HORNER. Department of 


- Oxalic acid synthesis and calcium oxalate 

crystal production in roots of Yucca torreyi L. 

Cytochemical and autoradiographic analyses. 

Glycolate oxidase was localized in peroxisomes of 

root cells by using the cerium chloride technique. 

Reactive peroxisomes were identified by the heavy- 

metal precipitate and by x-ray elemental analysis for 

cerium. Reactive peroxisomes were found in all 

parenchymatous cells except in those forming files of 

calcium oxalate crystal idioblasts. There was no 

apparent concentration of reactive peroxisomes in 

parenchymatous cells around the idioblasts. Incor- 

poration of 14C-ascorbic acid into primary roots for 

periods of 3, 6, 13, 18, and 24 hours showed that the 

label reaches the developing idioblasts within 3 

hours and is incorporated into the raphide crystals. 

By 12 hours, almost all of the label is found in the 

idioblasts and crystals. Concentration of label in 

the cytoplasm of idioblasts is over the crystallo- 

plastids. The label is eventually added to the ends 

of already partially formed crystals indicating that 

their growth is bidirectional. Use of lycorine, an 

inhibitor of ascorbic acid synthesis, and 14C_ 

glycolic acid, another major precursor of oxalic acid 

in other plants, supports the results presented here. 


}(HAN, M. A. and I. A. UNGAR. Department of 

Botany, Ohio University, Athens, Ohio 45701 - Seed 

polymorphism and germination responses to salinity 

stress in Atriplex triangularis. 

The seeds of Atriplex triangularis exhibited a very 

pronounced morphological and physiological seed 

polymorphism. Seed size which varied from 1.0 to 

2.8mm was found to be a predictor of the likelihood 

of successful establishment through its effect upon 

germination and seedling vigor. Large seed had a 

mean dry weight of 2.44?0.16mg and a mean length of 

2.45?0.24mm, medium seeds had a mean dry weight of 

1.21?0.10mg and mean length of 1.78?0.19mm and small 

seeds had a mean dry weight of 0.64?0.04mg and a 

mean length of 1.27?0.10mm. The degree of salt 

tolerance increased progressively with increasing 

seed size. Seeds from all size classes that were 

initially treated with 2 to 5% NaCl had from 85 to 

100% germination after being immersed in distilled 

water for 6 days, indicating a transitory adverse 

effect of salt stress on germination. Seedling dry 

weight was found to be related to initial seed size. 

Salt stress inhibited seedling growth. GA3 was 

found to alleviate some of the dormancy in seeds 

induced by high salt concentrations. The relation- 

ship between germination and seedling growth under 

salt stress to the establishment of plants in native 

populations will be discussed. 

KONING, ROSS E. Department of Biological Sciences- 

Botany, Rutgers University, Piscataway, NJ 08854 

- The roles of plant hormones in style and stiga 

growtn l na a aT n t o ra. 

StyTe an iti s ot i tlmafionaatTima unfolding, and 

the roles of plant hormones in these processes in 

Gaillardi'a grandiflora Van Houtte were investigated. 

Style and otigma elongation in vivo began just after 

anthesis, and style elongation was accompanied by epi- 

dermal cell elongation (greatest near the stigma) and 

a fresh weight increase, but not by cell division or 

a dry weight increase. The stigma unfolded after the 

style and stigma elongated. Style-stigma units ex- 

cised from young disc flowers of this composite were 

measured as they responded to plant growth regulators 

applied singly, and in sequential and simultaneous 

combinations, in vitro. Style and stigma elongation 

were promoted by auxin, were inhibited by gibberel- 

lin and ethylene, and were unaffected by other growth 

regulators. Endogenous auxin levels and ethylene 

production showed parallel variation and endogenous 

gibberellin levels showed inverse variation with 

style and stigma elongation. Stigma unfolding was 

more sensitive to auxin applications and was promoted 

by applied ethylene. Ethylene production showed 

parallel variation and endogenous auxin levels showed 

inverse variation with stigma unfolding. AVG and 

Co2+ application decreased auxin-induced style 

elongation, and fusicoccin promoted all of the growth 

responses of style-stigma units in vitro. A 

gi bberel l i n-auxi n-ethylene-acid growth interaction 

mode of control is proposed for these three growth 

processes. 

KONING, ROSS E. AND MANDY M. RAAB. Department of 

Biological Sciences-Botany, Rutgers University, 

Piscataway, NJ 08854 

- The effects of applied plan growth substances 

on gro h ofI poema-il corola an fT,ei 

It is lWdel a gibbeFe1ins pomote coro I I a 

growth in various plant species, and in 1973 Murakami 

found that gibberell ins caused rapid fil ament elonga-


tion. The present results confirm and extend these 

findings. Corolla width and length and filament 

length were measured as the isolated parts responded 

to applications of the growth substances in vitro. 

Applied gibberellins greatly promoted both corolla 

and filament elongation with maximum effect at 10-5 M. 

The gibberellin synthesis inhibitors, AMO-1618 and 

CCC, had no effect on growth. Thus gibberellin synthesis 

is probably not as important a part of the 

growth mechanism as gibberellin transport into the 

flower from outside, or conversion from bounlJ or inactive 

forms. Applied auxins and cytokinins inhibited 

growth slightly, but only at herbicidal concentrations 

(10-4 M). ACC, an ethylene biosynthesis precursor, 

greatly inhibited while AVG, an ethylene biosynthesis 

inhibitor, enhanced gibberell in-induced 

growth. Applied abcisic acid had no effect upon 

either corolla or filament growth. Fusicoccin, a 

proton pump stimulator, promoted early growth while 

vanadate ion, a purported proton pump inhibitor, 

greatly reduced growth. Thus it is conceivable that 

the natural growth mechanisms for filaments and corollas 

of morning glories involve both gibberellin as a 

positive modulator and ethylene as a negative modulator. 

Furthermore, the mode of action of gibberellin 

in these flower parts may partially include acid 

growth stimulation. The proposed mechanism must be 

tested for paral l el variation of gi bberel l in and inverse 

variation of ethylene production with respect 

to corolla and filament growth. 

LAMOTTE, CLIFFORD E. Department of Botany, Iowa 

State University, Ames, IA 50011. 

- Exogenous abscisic acid causes reorientation of 

branch shoots of Solanum andigena. Test of the 

Snow hypothesis of apical dominance. 

Four-leaf cuttings are fed through their cut stem 

bases with a solution consisting of modified Hoagland's 

minerals, N6-benzyladenine (BA), and abscisic 

acid (ABA). Two kinds of experiments are to be described. 

The first involves the transformation of 

leafy shoots to stolons, which is promoted by apical 

dominance in whole plants and by apically applied 

IAA or basally applied ABA in decapitated cuttings. 

These results are consistent with the Snow hypothesis. 

Similar effects of ABA were reported earlier by 

E. Pfirsch and T. Makosso (Can. J. Bot. 58:466-70. 

1980) in Stachys silvatica. The second involves the 

transformation of stolons to leafy shoots, which is 

evoked by a release from apical dominance in rooted 

plants or by basally applied BA in cuttings. ABA 

inhibits the branch reorientation characteristic of 

this transformation without affecting other morphological 

attributes of the branch. 

1AKSYIIOWYCH, ANDREW B.* JOSEPH A.J. 

ORKWISZEWSKI. Department of Biology, 

Villanova University, Villanova, PA 19085. 

- Specificity of fluorophenylalanine 

induced Avena coleoptile elongation. 

Studies with para-,ortho-, and meta-fluoro- 

phenylalanine demonstrate that isomneric 

specificity exists in the effects of these 

analogues on Avena coleoptile elongation, 

in vivo chlorogenic acid levels and extract- 

able L-phenylalanine ammnonia-lyase activity. 

The effects of other halogenated phenylala- 

nine analogues are now under investigation. 

To date we have demonstrated that only 

fluorophenylalanine promotes coleoptile ex- 

tension growth. Chloro-, bromo-, and iodo- 

phenylalanine inhibit coleoptile elongation. 

Similarly, only fluorophenylalanine treat- 

ment results in decreased chlorogenic acid 

levels. Incubation of coleoptile segments 

with the other halogenated phenylalanines 

protects against chlorogenic acid loss. 

These data are consistent with the hypo- 

thesis that fluorophenylalanine promotes 

coleoptile elongation by lowering the levels 

of potentially phytotoxic low molecular 

weighit phenols. 

Moffler, Mark D. and Michael J. Durako. Florida 

Dept. of Natural Resources, Bureau of Marine 

Research, 100 Eighth Ave. S.E., St. Petersburg, FL 

33701. - Axenic culture of Thalassia testudinum 

Banks ex K8n g Hdrochari taceae) . 

Axenic culture of seagrasses has not previously been 

achieved. Thalassia testudinum cultures were estab- 

lished and grown in the absence of other detectable 

organisms. Cultures were initiated using surface 

sterilized seeds (70% v/v ethanol in seawater for 30 

sec) which were aseptically dissected from surface 

sterilized fruits (5% v/v clorox in seawater at pH 8.0 

for 10 min followed by two sterile seawater rinses). 

Seeds were rinsed three times in sterile seawater and 

placed in a holding dish containing sterile seawater 

and penicillin-streptomycin (200 units/ml) for five 

minutes. Seeds were placed in 80 ml culture tubes 

containing 35 ml marine agar as a rooting substrate 

and 40 ml of defined seawater media (320/oo, pH 8.0). 

Seedlings and culture media were analyzed for micro- 

bial infection after six weeks of culture utilizing 

standard marine bacterial/fungal isolating procedures 

and SEM. Mean seedling (n=24) leaf area and root 

length after three months of culture were 331.5 mm2 

? 195.6 mm2 and 21.8 mm ? 18.7 mm respectively. 

Axenic seagrass cultures will be important for physio- 

logical studies such as nutrient assimilation kinetics, 

rhizosphere and phyllosphere microbial interactions 

thru mono- and polyxenic culture and seagrass-epiphyte 

interactions. This procedure will also provide an 

aseptic tissue source for tissue culture studies. 

PATERSON, KAROL E. Stauffer Chemical Company, 

Richmond, CA 94804 - Shoot multiplication in 

Hel ianthus annuus. 

Shoot multiplication from cultured Helianthus annuus 

shoot apices can be induced by two of the cytokinins 

- benzyl adenine and kinetin. Zeatin and isopentenyl 

adenine are ineffective as promoters of shoot multiplication. 

The largest number of shoots is obtained 

by cutting a shoot apex in half longitudinally and 

culturing both halves on BA-medium. High BA concentrations 

promote tiny abnormal rosette shoots with 

poor survival. Gibberellic acid also promotes shoot 

multiplication. The multiple shoots tend to flower 

while still in culture. Flower heads have been 

observed after as little as three weeks in culture. 

Both the cytokinins and GA affect flowering. There 

is also a possible interaction between cytokinin 

and ethylene in this system.

RANSOM, J. STEVEN* and RANDY MOORE. Biology 

Department, Baylor University, Waco, TX 76798. 

- Curvature of primary and lateral roots of 

Phaseolus vulgaris in response to removal of 

the root tip. 

Root tips of primary and lateral roots of Phaseolus 

vulgaris were cut longitudinally and half of each of 

the root tips excised. These half tipped roots were 

then oriented in different directions with respect 

to gravity in order to quantify the resulting graviresponses 

(i.e., curvatures). Primary roots bend 

toward the uncut side of the root, regardless of how 

the roots are oriented. The strongest response 

(91.90) occurs when the roots are oriented horizontally 

with the uncut side down. The weakest response 

(30.80) is encountered when the roots are 

oriented horizontally with the uncut side up. 

Lateral roots respond similarly, except that the 

magnitudes of the curvatures in lateral roots are 

substantially less than in primary roots. Untreated 

primary roots (controls) curve 70.10 downward when 

oriented horizontally. The corresponding value for 

lateral roots is 3.90. If the entire root tip is 

excised there is little or no curvature in either 

type of root. Therefore, columellas of both primary 

and lateral roots of Phaseolus vulgaris produce 

sufficient inhibitor to induce root curvature. The 

failure of intact lateral roots to respond to gravistimulation 

is due not to the absence of inhibitor 

production by the root cap, but rather to the failure 

of these roots to sufficiently redistribute the inhibitor 

in response to a gravitational stimulus. 

This is probably due, in large part, to the small 

size of the columella tissue in lateral roots. 

SIMON, JEAN-PIERRE* and CATHERINE POTVIN. Departement 

de Sciences Biologiques, Universite de 

Montreal, Quebec H3C 3J7 and Botany Department, 

Duke University, Durham, North Carolina 27706. 

Effect of CO2 enrichment and temperature on 

kinetic and thermal properties of Phospho-enol 

pyruvate carboxylase in 2 genotypes of Echinochloa 

crusgalli (L.) Beauv., a C4 grass weed. 

Two populations of Echinochloa crusgalli (Quebec, 

Mississippi) were grown at the Duke Phytotron under 

2 thermoperiods (280/220C, 210/150C day/night) and 2 

CO2 regimes (350 and 675 ppm). Thermostability, 

energy of activation (Ea), Km (PEP) and specific 

activity of Phospho-enol-pyruvate carboxylase (PEPc) 

were analyzed in partially purified enzyme preparations 

of plants grown for 5 weeks. Thermostability 

of PEPC was significantly higher in Mississippi 

plants and was not modified by temperature acclimation 

or CO2 enrichment. Ea (Qlo 300/200C) for PEPc 

was significantly lower in Quebec plants (11 Kcal/ 

mol ) as compared to Mississippi (15 Kcal/mol ) and 

no acclimatory shifts were observed. Significantly 

higher kms (1-1.2 mM PEP) at 200C assays were 

obtained for Mississippi as compared to Quebec plants 

(0.4-0.5 mM PEP) but were similar at 300C and 400C 

assays, ranging from 0.3 to 0.6 mM PEP. PEPc 

activity was significantly higher for Quebec plants 

when measured on a leaf fresh weight, leaf area or 

protein basis but not on a chlorophyll basis. 


Significantly higher PEPC activity for both genotypes 

was observed for plants acclimated at 210/150C or 

grown at 675 ppm C02. 

WEBB, DAVID T.* Department of Biology, Queen's Uni- 

versity, Kingston, Ontario, K7L 3N6 and OLGA DIAZ 

SANTIAGO, Department of Biology, University of 

Puerto Rico, Rio Piedras, P.R. 00931. 

- Cytokinin induced bud and shoot formation by 

Pinus caribaea embryos in vitro. 

Embryos of Pinus caribaea were cultured on Shenk and 

Hildebrandt (SH) medium with and without Benzyla- 

denine (BA). BA was tested at 0.5, 1.0 and 5.0 mg 

1-1. Whole embryos were excised and placed horizon- 

tally on agar (0.9% W/v) medium and incubated at 29 C 

light; 25 C dark with 12 h photoperiods of 2 klux 

fluorescent light. Embryos taken from dry seeds de- 

veloped a few buds after 9-10 weeks on iMedium with 

5.0 mg . 1-1 BA. Little to no bud formation occurred 

at the other BA concentrations. Embryos taken from 

seeds pretreated by dark incubation at 27 C on half- 

strength SH medium formed buds at-all BA concen- 

trations. Buds were evident after 4-6 weeks in the 

latter case, and at 5.0 mg . 1l1 a callus compcsed of 

many buds developed. When embryos and callus with 

buds were transferred to hormone-free SH medium, stem 

elongation occurred after the second subculture. 

Control embryos germinated normally and did not pro- 

duce buds in both experimental procedures. 

WILSON, KATHRYN 

J. Department of Biology, Indiana 

University-Purdue University at Indianapolis, 

Indianapolis, Indiana 46223 

- Callus growth and embryogenesis in tissue 

cultures of Asclepias tuberosa L. (Asclepiadaceae). 

Tissue cultures of Asclepias species provide an ex- 

perimental system suitable for specifically defining 

the biochemical and physical parameters of differen- 

tiation and growth of the cell type, the laticifer. 

Since laticifers typically present in Asclepias mem- 

bers differentiate in zygotic heart stage embryos, 

experiments were undertaken to determine culturemedia 

supporting rapid callus growth and ultimately promo- 

ting the most prolific asexual embryogenesis. Stem 

explants callused most rapidly when derived from 

seedlings no older than 25-30 days. To derive callus, 

explants were maintained on several combinations of 

2,4-D(O-4.0 mg/l) and benzyladenine (BA) (0-2.5 mg/l) 

incorporated into a basic Murashige-Skoog (MS) medium. 

After 33 days greatest callus growth was obtained on 

media supplemented with 0.5 mg/l 2,4-D and 0.5 mg/l 

BA. Significantly greater numbers of embryoids were 

obtained on media supplemented with 0.5 mg/l 2,4-D 

combined with 1.0, 2.0, or 2.5 mg/l BA and their 

numbers were increased by transferring one month old 

callus to MS medium supplemented with .5 mg/l BA and 

either no or a relatively high concentration of (6.0 

mg/i) of 2,4-D. Embryoids differentiate within pro- 

embryogenic cell clusters. High concentrations of 

auxin promote embryoid development most similar to 

normal embryogeny. The effect on laticifer differen- 

tiation in embryoids proliferated on high auxin con- 

centrations currently is being investigated.

90 Phytochemical Section 


PHYTOCHEMICAL SECTION 

CRAWFORD, Daniel J.*, and EDWIN B. SMITH. Department 

of Botany, The Ohio State University, Columbus, 

OH 43210, and Department of Botany and Microbiology, 

University of Arkansas, Fayetteville, AR 72701.- 

A1lozyme variation in Coreopsis grandiflora 

(CompositaeT :divergence among the three diploid 

varieties and origin of the hexaploid variety. 

Coreopsis grandiflora is an outcrossing, herbaceous 

perennial occurring primarily in the southeastern 

United States. The species is variable morphologically, 

and this variation is now accommodated taxonomically 

in four varieties: var. grandiflora; var. 

harveyana (A. Gray) Sherff; var. saxicola (Alex.) 

E.B. Smith and var. lonaipes (Hook.) T.&G. Three of 

the varieties are diploid (n=13) whereas var. longipes 

is hexaploid. Populations of the diploid varieties 

are usually highly interfertile. An electrophoretic 

study of nine soluble enzymes coded by 19 

genes revealed no differentiation between the diploid 

varieties. Comparable levels of genetic variation 

were found in populations of each diploid variety and 

within each variety as a whole. The hexaploid var. 

longipes contains the same alleles as the diploid 

varieties, suggesting its origin exclusively within 

C. grandiflora. This hypothesis is concordant with 

data from flavonoid chemistry and morphology. 

EMERSON, JEAN. Biology Department, Saint Mary 

College, Leavenworth, Kansas and Botany Department, 

University of Kansas, Lawrence, Kansas 66045 

and BRUCE A. BOHM. Botany Department, University 

of British Columbia, Vancouver, B.C. V6T 1155. 

- Flavonoid Variation between Chromosomal Races of 

Calycadenia ciliosa (Compositae)_. 

Calycadenia is a qenus in Mladiinae comprising about 

12 annual, self-incompatible species that are found 

principally in California. Chromosome numbers of 

n = 4,5,6,7 and 9 are known. The genus displays contrasting 

modes of evolution with species such as C. 

ciliosa that consist of morphologically similar and 

chromosomally distinct races, and other species, similar 

to C. multiglandulosa, that consist of races 

that are morpholopically distinct but lack chromosomal 

differentiation. Calycadenia ciliosa (n = 6) consists 

of at least five chromosomally distinct races. 

High levels of structural heterozygosity within some 

populations make racial assignment difficult. The 

present report describes preliminary studies of the 

flavonoid chemistry of certain populations of C. 

ciliosa. Two dimensional thin layer chromatography 

has shown a rich and complex array of pipments that 

differ between populations. Structural studies to 

date have identified glycosides of luteolin, kaempferol, 

and quercetin. 0-Methylated derivatives of 

the flavonols have also been detected including the 

novel 5,3' ,4-trihydroxy-3,6,7,2'.-tetramethoxyflavone. 

Nuclear magnetic resonance, mass spectral, and ultraviolet 

data will be presented in support of this 

assignment. 

KNOX, MICHAEL J.*, STEVEN 0. LINK, and W.DENNIS 

CLARK. Department of Botany & Microbiology, 


- Geographical variation of the alkaloids in 

Mammillaria microcarpa (Cactaceae)-. 

Cortical tissue extracts of M. microcarpa from several 

sites in Southern Arizona were analyzed for 

variation in beta-phenethylamine composition by high 

performance liquid chromatography. Three phenolic 

compounds, tyrami'ne, N-methytyramine, and hordenine, 

were found to occur throughout the natural range of 

the species. A fourth constituent, 3,4-dimethoxybeta-phenethylamine 

was generally less. distributed 

and present in trace amounts. Plants located at 

lower elevations and in hotter soils (hyperthermic 

arid) contained higher levels of tyramine and N- 

methyltyramine than did plants at higher elevations 

in cooler soils (thermic semiarid). While tyramine 

and N-methyltyramine showed significant differences 

among sites, there was no evidence of significance 

for hordenine or 3,4-dimethoxy-beta-phenethylamine. 

It is suggested that the simpler beta-phenethylamines 

are more responsive to differences in their 

environment then are the more biochemical complex 

structures. We conclude that the concentration of 

these compounds is probably a result of an adaptive 

response to ecogeographic gradients. 

LEVY, MORRIS. Department of Biological Sciences, 

Purdue University, West Lafayette, IN 47907. 

- Allozyme variation among populations: an index 

of the significance of gene flow in plant species. 

Observations of limited gene dispersal potential and 

of genetic subdivision within populations have been 

offered as evidence that gene flow is not a signifi- 

cant force maintaining cohesion in a species gene 

pool. However, long-distance seed dispersal, of 

essentially immeasurable magnitude and frequency, 

must occur during colonization episodes to account 

for population dispersion patterns and the size of a 

species range. Does such gene migration, supplement- 

ed by interpopulational pollen movement, recur suffi- 

ciently to prevent stochastic divergence among es- 

tablished populations? The best available data on 

the issue are standardized allelic variance (FST) 

estimates based on allozyme variation among popula- 

tions; such estimates can be related to island-model 

expectations for neutral alleles under migration- 

based panmixia. Relative to the FST expected with a 

homogenizing migration rate of one per generation, 

observed FST values for ca. 30 species are distribut- 

ed dichotomously according to breeding system. Uni- 

parental breeders exhibit heterogeneity among popula- 

tions which belies cohesive gene flow but biparental 

breeders do not. Indeed, though the values in the 

latter group are 2-10 times greater than in some 

highly vagile animals, e.g. Drosophila, they are 

generally on the order of those for blood group loci 

among human populations where significant gene flow 

is presumed to occur. The dichotomy between breeding 

systems probably reflects differences in colonization 

dynamics as well as in the probability of incorpora- 

tion of migrant genes. Thus, though gene f low is 

unquestionably restricted in plant species, it can 

not be dismissed as a potentially homogenizing in- 

fluence in species where outcrossing is at a premium.

LIU, MEEI Y*,SUMANA BANERJEE,JOHN RUFFIN 

Department of Biology,North Carolina Central 

University, Durham,N,C.,27707. 

-A preliminary study of the effects of some 

common environmentally occuring gaseous pollu- 

tants on free amino acid content of certain 

airborne pollen grains. 

The purpose of this study is to compare the free 

amino acid content of both contaminated and un- 

contaminated pollen grains. The uncontaminated 

pollen grains of Quercus rubra,Ulmus pumila,and 

Festuca elatior are exposed to common atmosphe- 

ric pollutants such as SO2, NO2, and CO. The 

above pollen grains are collected aseptically 

and contaminated at Environmental Protection 

Agency,Research Triangle Park,N.C..After contami- 

nation, the free amino acids are analyzed using 

thin-layer chromatography. Preliminary analysis 

indicates that there is a great variation in the 

number of amino acids after the pollen grains 

are contaminated. 

/ * 

NASCIMENTO, JOSE C. and LANGENHEIM, JEAN H. 

Centro Nacional de Pesquisas da Seringueira e 

Dende, Manaus 69,000, Amazonas, Brazil and 

Division of Natural Sciences, University of 

California, Santa Cruz, CA 95064. 

- Leaf sesguiterpenes and phenolics in Copaifera 

multijuga (Leguminosae) on contrasting soil types 

in Amazonian rainforest. 

Copaifera multijuga, a resin-producing legume which 

also contains abundant phenolic compounds, is a 

relatively common emergent component of central 

Amazonian rainforests. Differences in amount of leaf 

sesquiterpenes and phenolics (including tannins) were 

not significant in 22 C. multijuga trees occurring on 

contrasting soils (i.e. sandy, nutrient-poor vs. 

clayey, nutrient-richer). These results differ from 

those considering phenolics and alkaloids among 

numerous species in African rainforests on similar 

contrasting soils, which generally support a current 

hypothesis that plants on nutrient-poor soils 

probably invest more heavily in secondary compounds 

(particularly phenolics) as an herbivore defense 

than those on nutrient-rich ones. Results with 

C. multijuga also differed in that: a) two 

secondary compounds occurred in the mature leaves, 

and b) although soil nutrients in the contrasting 

types differed significantly, most leaf nutrients 

did not. 

RICHARDSON, P.MICK. New York Botanical Garden, 

Bronx, New York 10458. - C-glycosylxanthones in 

the angiosperms. 

The occurrence of C-glycosylxanthones in the angiosperms 

is reviewed. The compounds occur in 96 

species in 28 genera in 19 families and are divided 

between the dicots and monocots 60:18:13 and 30:10:6 

respectively. Contrary to earlier claims, the compounds 

appear to be of little taxonomic value at any 

level. There is no correlation between the occurrence 

of C-glycosylxanthones and morphological advancement. 

The main value of the compounds lies in 

their pharmacological properties. 

SCHILLING, EDWARD E. Department of Botany, 

University of Tennessee, Knoxville, TN 37996-1 100. 

-Flavonoids and the systematics of Solanum section 

Solanum. 

Leaf flavonoids of the eleven North American species of 

Solanum section Solanum were characterized. Eleven 

Phytochemical Section 91 

flavonols, priniarily glycosides of quercetin and 

kaempferol, were isolated. Most species have a relatively 

simple flavonoid pattern with one or a few glycosides. 

The most distinctive pattern occurs in S. sarrachoides 

which is unique in having free flavonoid aglycones as 

well as 3-methoxylated compounds. Although not all 

species have unique flavonoid complements, flavonoid 

distribution is consistent with current taxonomy of the 

section. Flavonoid data are of little help in determining 

ancestries of polyploid species, but do appear to rule out 

S. sarrachoides as being a progenitor of S. villosum and 

S. nigrum. 

SPENCER, KEVIN C.* and DAVID S. SEIGLER. 

Department of Botany, university of Illinois, 

Urbana, IL 61801. - Coevolutionary Significance of 

Cyanogen Diversification in Passiflora. 

The Coevolution of Passiflora ana Heliconius has been 

the subject of much research. It has been clearly 

demonstrated that the system is complex and that 

morphological, ecological and behavioral factors play 

major roles in the interrelationships of these 

organisms. However, we feel that the host plant 

chemistry is central in this system. Cyanogenic 

glycosides and cyanohydrins were isolated from over 

30 species of Passiflora, including most of the major 

subgenera. Analysis of their structures reveals a 

tremendous diversity in the types of cyanogens produc- 

ed. The distribution of these cyanogens reflects 

taxonomic relationships within the genus. We have 

found that a strong correlation exists between host- 

plant preference of Heliconius larvae and the type of 

cyanogen produced by the plant species, and that 

these compounds are biologically active. We propose 

that the diverse array of cyanogens produced by 

Passiflora has arisen in direct response to herbivory 

by Heliconius larvae, and forms the proximal basis 

for the coevolutionary interactions between the two. 

The actual mechanism of adaptive response by 

Heliconius to production by its host of a novel 

chemical defense may involve a change in the B-gluco- 

sidases present in its digestive system. 

*;TAR, AURA and ALBERTO MANCINELLI. Department 

of Biological Sciences, Columbia University, 

New York, NY 10027. *Trenton State College, 

Trenton, NJ 08625. 

- Effects of inductive and long term irradiation 

on the flavonoid complement of Avena sativa L. 

seedlings. 

Light control of flavonoid synthesis has been 

demonstrated in a select number of plant species. 

Phytochrome involvement seems to be universal, and 

in some species a blue-light photoreceptor has been 

shown to be operative. Additionally, responses to 

light treatments seem to be dependent on the 

physiological state of the orqanism. In this study 

etiolated four and six day old seedlings were 

treated with inductive red and far red irradiation 

as well as long term irradiation under UV, blue, 

red, far red, and white light. Total flavonoid 

complements under each of these reqimes were 

measured. Also, the detailed kinetics of changes 

in the accumulation of vitexin and isovitexin 

derivatives was determined. Avena seedlings 

accumulate vitexin and isovitexin derivatives 

differentially under specific light regimes. 

Flavonoid synthesis is under the control of the 

phytochrome system as well as that of a blue-light 

photoreceptor. Blue light is more effective in 

fl avonoi d synthesi s i n si x day ol d eti ol ated 

seedlings than in four day old etiolated seedlings.

92 Pteridological Section 

URBATSCH LOWELL E., NIKOLAUS H. FISCHER AND 

GUSTAVO OBER. Department of Botany and Department 

of Chemistry, Louisiana State University, Baton 

Rouge, LA 70803 - The sesquiterpene lactones of 

Calea (Asteraceae) - a preliminary report. 

The genus Calea L. contains approximately 100 species 

of mostly shrubs that grow in the montane regions of 

the Neotropics. Mexico, Central America, the north- 

ern Andes, and Brazil contain the greatest number of 

species. In an attempt to assess the interrelation- 

ships among the species of this genus, comparative 

sesquiterpene lactone studies are being carried out 

to complement our morphological and cytological inves- 

tigations. Lactone studies have been completed for a 

number of species from diverse geographical regions. 

The basic skeletal types of compounds found in Calea 

include germacrolides, eudesmanolides and heliango- 

lides. Calea ternifolia HBK and C. urticifolia 

(Mill.) DC. from Mexico exhibit virtually identical 

complements of compounds. Calea trichotoma Dn. Smith 

from sotithern Mexico contains only eudesmonolides 

similar to those reported for the Brazilian C. rotun- 

difolia (Less.) Baker by Bohlmann et al. in 1981. 

Calea berteriana DC. and C. subcordata Blake from 

northern South America are similar in their lactone 

substituents, but different from the other species of 

Calea. 

WALLACE, J. W., CHAPMAN, M., SULLIVAN, J.E. and 

BHARDWAJA*, T.N. Western Carolina University and 

*Government College, Ajmer, India.--Polyphenolics 

of the Marsileaceae and their phylogenetic sig- 

nificance. 

Species of the Marsileaceae represent a unique group 

of pteridophytes of questionable origin. The poly- 

phenolic profiles of representative species,which 

include flavonol-3-0-mono-and di-glycosides, C-gly- 

cosylflavones and C-glycosylxanthones, were demon- 

strated to have chemical features in common with the 

primitive leptosporangiate ferns, especially the 

Hymenophyllaceae. Intergeneric relationships in the 


BILDERBACK, D. E.* and J. H. SLONE. Department of 


- The apical organization of Selaginella krauss- 

iana. 

Selaginella kraussiana has a prostrate dorsiventral 

stem with small leaves on the dorsal surface and 

large leaves laterally inserted. When viewed with 

the SEM, the distal portion of the apex consists of 

large rectangular cells with their long axes oriented 

perpendicular to the dorsiventral plane of symmetry. 

When the apex is sectioned in a plane perpendicular 

to the dorsiventral plane of symmetry, large hemi- 

spherical and rectangular cells are observed distal- 

ly. When the apex is sectioned in a plant parallel 

to the dorsiventral plane, one triangular and several 

rectangular cells are found at the most distal por- 

tion of the apex. The apical cells have large nuclei 

and cytoplasm filled with numerous small vacuoles. 

Ultrastructurally, the walls between the apical cells 

are thin and traversed by numerous plasmadesmata. 

Usually, a large undifferentiated plastid is assoc- 

PTERIDOLOGICAL SECTION 

family based on morphology, cytology, fossil evidence 

and the polyphenolic profiles indicate that Regnel- 

lidium is probably not a phylogenetic intermediate 

in a complexion or reduction series between Marsilea 

and Pilularia. The cturrent evidence indicates that 

Regnellidium was probably derived from Marsilea. 

WHITE, ROSEANN S. and HARVEY A. MILLER* 

Department of Biological Sciences, University of 

Centra l Florida, Orlando, FL 32816. - 

Flavonoids of developmental stages in 

Spathiphyllum inflorescences. 

Samples of Spathiphyllum "Maunaloa" inflorescences 

at progressive developmental stages and vegetative 

leaves were harvested simultaneously from a large, 

sheltered, monoclonal planting on the University of 

Central Florida campus. Six stages were defined by 

spathe color matched to a Munsell Color Cascade and 

by morphologic condition. Spathe, spadix and 

peduncle were separated for each inflorescence 

before drying at 450C. Each structure from each 

stage, represented by several inflorescences, was 

extracted in absolute methanol. Extract was 

spotted on Whatman 3MM paper for two dimensional 

chromatography. Developed chromatograms were 

examined initially by long wave UV light with and 

without ammonia fumes. Flavonoid composition of 

leaf blades differed markedly from that of either 

the spathe or spadix. For the spadix, flavonoids 

were uniform through post-anthesis stages but a 

probable flavone was lacking in pre-anthesis. 

Spathe flavonoid diversity increased after anthesis 

with at least three compounds found only after 

total dehiscence of anthers. These studies 

demonstrate phytochemical diversity among plant 

organs of Spathiphyllum and confirm the necessity 

for consideration of developmental stages in 

chemical characterization of the inflorescence. 

iated with the nucleus of each cell. Some sphero- 

somes are present, but mitochondria, endoplasmic 

reticulum and dictyosomes are poorly represented. 

HAUFLER, CHRISTOPHER H. Department of Botany, 

University of Kansas, Lawrence, KS 66045. - 

Predicted mechanism and natural operation of out- 

crossing in a homosporous fern. 

Since they have potentially bisexual gametophytes, it 

has generally been assumed that homosporous ferns are 

highly inbred and genetically homozygous. Work with 

agar-cultured gametophytes of the xeromorphic species 

Bommeria hispida, however, demonstrated a mechanism 

for obligate outcrossing through antheridiogen (hor- 

mone) control of gametangial initiation and self- 

incompatibility of individual gametophytes. Electro- 

phoretic analysis of natural sporophyte populations 

showed that based on analysis of 10 enzyme systems 

and 13 loci, B. hispida has an average of 2.67 

alleles per locus, a percent polymorphic loci value 

of 69.2 and an average individual heterozygosity of 

0.193. These values are comparable to other out-

crossing plant species. Further, the cytosolic locus 

of phosphoglucoisomerase was heterozygous in all 

populations, proving that each of the plants sampled 

resulted from outcrossing between two, genetically 

different gametophytes. Data from natural popula- 

tions, therefore, correlate precisely with the out- 

crossing mechanism predicted through laboratory 

analysis. The coordination of evidence from gameto- 

phytic and sporophytic generations in determining 

breeding systems in homosporous pteridophytes pro- 

vides a powerful tool for exploring their reproduc- 

tive biology and levels of genetic variability. 

Expansion of this technique in analyses of other taxa 

may have a significant impact on our concepts of 

evolutionary mechanisms in the ferns. 

HAUFLER, CHRISTOPHER H.* and DOUGLAS E. SOLTIS. 

Department of Botany, University of Kansas, Lawrence, 

KS 66045 and Department of Biology, University 

of North Carolina, Greensboro, NC 27412. - 

Diploidy in ferns: a general phenomenon? 

Klekowski has calculated that the average haploid 

number for ferns is 57.05 (while that for angiosperms 

is 15.99) and has estimated 

species could be considered 

that up to,96% of fern 

polyploid. As discussed 

by Wagner and Wagner, there are two categories of 

polyploidy in ferns; paleopolyploidy, representing 

the extant, basic, generic chromosome complements, 

and neopolyploidy, involving multiplication of these 

basic sets. Klekowski has argued that paleopolyploidy 

combined with homoeologous chromosome pairing 

represents an evolutionary mechanism for storing and 

releasing variability. The actual operation of this 

mechanism requires that the homoeologous genomes 

differ genetically and that this variability be 

expressed. Another possibility is that paleopolyploids 

are genetically diploidized and do not evidence 

polyploid effects. One assay for polyploid 

expression involves electrophoretic analysis. If 

polyploids contain transcriptionally active homoeologous 

genomes, they should have more isozymes per 

enzyme system than would diploids. A preliminary 

survey of a diversity of fern taxa has shown that 

paleopolyploids have typical diploid banding patterns 

while neopolyploids demonstrate the multiplication of 

bands that would be expected through allopolyploidy. 

These data suggest that paleopolyploids are diploidized 

and do not show expression of homoeologous sets. 

Together with accumulating evidence that high outcrossing 

rates are maintaining genetic variability in 

natural fern populations, these new data on functional 

diploidy of paleopolyploids may force a reevaluation 

of the significance of high chromosome 

numbers in ferns. 

JERNSTEDT, J. A.* and M. A. MANSFIELD. Botany 

Department, University of Georgia, Athens, GA 

30602. 

- Polyacrylamide gel electrophoretic studies of 

proteins in Selaginella kraussiana stems, leaves, 

roots and "rhizophores." 

Fresh stems, ventral leaves, aerial roots (rhizo- 

phores) and subterranean roots of greenhouse-grown 

Selaginella kraussiana A. Br. were homogenized sep- 

arately, centrifuged and filtered to remove debris. 

Following addition of cold acetone, samples were 

stored overnight at -20C to precipitate proteins, 

centrifuged and the resulting pellets dried. Por- 

tions of each sample were resuspended in appropriate 

Pteridological Section 93 

buffers for one-dimensional and two-dimensional poly- 

acrylamide gel electrophoresis. Following electro- 

phoresis, gels were stained in 0.1% Coomassie brilli- 

ant blue for a minimum of 4 hr and destained over- 

night. Analysis of 1-D gels showed 15-30 proteins 

separated on the basis of molecular weight, while 

two-dimensional separation and staining resulted in 

visualization of some 50 protein spots. The majority 

of proteins were common to stems, ventral leaves, and 

aerial and subterranean roots. However, qualitative 

and quantitative differences in banding and spot pat- 

terns existed between organs. The results obtained 

with these techniques complement information from 

anatomical, developmental and physiological studies 

of Selaginella rhizophores and provide an additional 

source of evidence for considering organ homologies 

within the genus. 

KARRFALT, ERIC Department of Biological Sciences 

Fordham University, Bronx, NY 10458. - The 

sequence of root initiation in Isoetes andicola 

var. gemmifera (W. Rauh) L. D. Gomez. 

The sequence of root initiation in this plant 

(originally described as Stylites gemmifera) is a 

novel modification of the sequence seen in other 

species of Isoetes. In typical species, which bear 

their roots on the lower surface of the corm, roots 

are initiated repeatedly at definite sites along the 

length of the linear, root-producing meristem. A 

sequence of initiation begins at or near the center 

of the length of the root-producing meristem and 

proceeds bidirectionally to each of the sites of 

initiation along the meristem. Each such sequence of 

initiation gives rise to a series of roots roughly 

parallel to the meristem. New series are begun 

before previous series are completed and the repeat- 

ed initiation of roots at the same locations along 

the root-producing meristem results in the alignment 

of the members of successive series into orthostichies 

which intercept the root-producing meristem at 

relatively high angles. The arrangement of the roots 

on the external surface of adult plants of I. andi- 

cola var. gemmifera superficially resembles that in 

other species, but the sequence of root initiation 

differs in four essential respects. In I. andicola 

var. gemmifera new series never begin at the same 

site of initiation as a previous series but always at 

one which is higher in the plant than that at which 

the previous series began. Roots are added to each 

series unidirectionally (upward). Individual series 

are very short, usually containing only two or three 

roots. Most sites of root initiation function but 

once, a few produce two root primordia, and none were 

seen to have produced more than two. 

MESLER, MICHAEL R. Department of 

Biological Sciences, Humboldt State 

University, Arcata, CA 95521. - 

Sexuality of a wild population of 

Equisetum gametophytes in northern 

California. 

One thousand three hundred and ninety four 

Equisetum gametophytes (subgenus 

Hippochaete) were collected from a one meter 

quad in September, 1982. Of these, 59% were 

female, 32% were male, and 9% were bisexual. 

At the time of collection, only 6% of female 

and bisexual gametophytes bore young 

sporophytes. Gametophyte size was

94 Pteridological Section 

correlated with sex; bisexual gametophytes 

were the largest (average area=36 mm ), 

followed by females (17.5 mm2) and males (5 

mm2). The distribution of male, female, and 

bisexual gametophytes was studied on a finer 

scale by dividing the quad into 10 cm 

subquads. Male and female gametophytes 

occurred together in 98 of the 100 subquads. 

There was considerable variation in the 

proportion of each sex in the subquads, but 

the overall distribution did not depart 

significantly from a random one. Although 

male gametophytes often predominate in 

crowded cultures, I found no correlation 

between density and percentage of males per 

subquad. The presence of male and female 

gametophytes in close proximity suggests 

ample opportunity for cross-fertilization. 

Further, it appears that the environmental 

factors that influence whether a spore 

develops into a male or a female gametophyte 

must operate on a very fine scale. 

* 

MOY TAVERA, CARMEN and CHARLES J. HILLSON, Dept. 

of Botany. The Pennsylvania State University, 

University Park, PA 16802. -- Light and electron 

microscope studies of spore structure in selected 

tropical ferns. 

-The spores of five species each of Bolbitis, 

Tectaria, Polybotria, Elaphoglossum, Ctenitis, 

Arthropteris, 

Leucostegia, 

Lomariopsis, Davallia, Nephrolepsis, 

Oleandra and Humata, all genera of 

tropical ferns, were studied by light and scanning 

electron microscopy. Thin sections of the sporoderm 

of certain species were also examined with the 

transmission electron microscope. Spore features 

were then compared and used to determine natural 

relationships. An exospore layer and a perispore 

layer were observed in spores of every species 

including some that had previously been described as 

lacking a perispore. The exospore is stratified into 

two layers in the area of the aperture. The perispore 

may be unilayered, bilayered or multilayered. In 

some cases the inner layer of the perispore exhibits 

a columellate structure similar to that observed in 

the exine of angiosperm pollen. This study indicates 

that spore characteristics can be used to show 

relationships among species and genera of ferns and, 

in certain cases, to delimit taxonomic groups. 

NESTER, JOAN E.* AND RONALD C. COOLBAUGH. Department 

of Botany, Iowa State University, Ames, IA 

50011. -Comparison of GA -induced spore germination 

in Anemia mexicana and Anemia phyllitidis. 

Gibberellic acid-induced spore germination in Anemia 

phyllitidis has been previously demonstrated to be 

pH dependent. The present investigation compared 

pH dependence and GA3 sensitivity in spore germination 

of A. mexicana and A. phyllitidis. Spores were 

germinated in the dark in culture media containing4 

50 mM MES buffer (pH 3.5-7.5) and GA3 (O to 5 x 10 

g/ml). Seven days after sowing, the number and 

percent of germinated spores were determined. The 

optimum pH for GA -induced spore germination in both 

species was 5.0-6.5 with 2-3 celled protonemal 

development. Less than 10% germination was observed 

in media at pH 4.0. Although the spore coat cracked 

open under these conditions, no protonemal development 

was observed. In A. mexicana spores cultured 

at pH 6.0, the maximum germination (75%) occurred 

with 5 x 10-4g/ml GA31 while only 6% of the spores 

germinated in 5 x 10- g/ml. Anemia phyllitidis, on 

the other hand, yielded 70% germination at 5 x 10-7 

g/ml GA3 and only 7% at 5 x 10-9 g/ml GA3. The pH 

optima for GA3-induced spore germination in A. 

mexicana and A. phyllitidis are quite similar. 

However, spores of A. phyllitidis are much more 

sensitive to GA3 than spores of A. mexicana. 

In a separate set of experiments, acidic ethyl 

acetate extracts (antheridiogen) of media of A. 

mexicana gametophyte cultures were partially purified 

by TLC and tested for their effect on spore germina- 

tion in the dark in A. mexicana. Two bands of 

germination inducing activity were clearly separated. 

PhALfiTALE, U'ATTA L. Department of Botany, 

K.T.H.A.GCollege, C angapur {o&ad, N'asik- 

422LO2, M.S0, India- 1n.Vitro studies in 

(2 ratopt'eris thaJictroides - i 

LPaves of 

cy..ntaininr, 

eratoateris 

a singlie 

thactrorogn) 

leaf bud meriSt+em(lbrn) 

.,were ciiltur'ed 

rrvnd.ium (I '). 

on t'.urashiqr'e Fn". 

r-bm ', hen culturdc 

Skk- ogc 

n l 

cc. nta Lnling T .< W %)ntlo t m/ 

l l) 

sUCrose (use c>.i !jf ic d +h a r?r 

.,4 Pvel. 3 - f rvbJ. e ca.l.s .. ubcultures 

vJp>re r.ade ,ter af 

sup1 i mentedic. 

evnerx 

L.A'1, 

2 J. day3s o)n 

c.inetiin ) 

t .5mg/1)~-,,-ic>.ro)s-s (2.;') to r.in>r cal 

w.itvhou}t rl if f e ri nt i-atl i.- n T. .1,1 co nt.ainingr 

(' 3m-,'1 ) n1in.tin i (1 .b5mrc /), suacr.cM (c; r 

lus 

.t 

Shiow,vel c lj US Cliffrcentiat'nn into k. -5O(c 

i mire pPlantlets 

pl,flant ets juven i 1 

rnr culture. 

?vc e .s anu 

F roi -above 

yV3'ung roots 

.ere ?ta+rhrcd ascepti.c-adlx,1 Th->sr 1 eves 

when cultured on r .S v%S with 1AA('.) .5mg/1), 

kinctin (0.5mng/l), 4ucrose (.1.5 caa 1us 

de vel cno'd fr rKcal rfro-win'., iDoints . The. 

roots cde1veo-ed callus on 1,'S containinfu 1A 

(O.5mgc/ ), ki n t n ( MgI J/ ) a nt- sucrose 

(2.)~ Lhm callus dieveloned only le.-ves vhen 

cultured on '2t lil'h kinetin (J-2m/), 

UC-crose (3 5;n) mu only roo s h hn , 1S ve , Cs 

.rr , i?'nte.c AIJJ T ,A (1 -2m/1) anu s u cro:).x {cjnrerc - tion c n,< t th hyt.ICs f rom 

(o r tec' s7c,:roQ\)hytcs w-s also possJibl 

(sucero&e,3 t. -..? :)) 

SLT." L t; . A let ,irtment of BotW.any 

?. T . H * oJa .J. ie n- U;.. L . Likd d , 

s 

.in '-Ora Qtf n1d'a.s tha Vittroi e - .iJ 

_ 

* 

t 

nIl.tl';vtr;. 'u ,~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 

tha.Lt rs s rod wC-e c 

' ( .!r /) i'.A tin 

. 

3;~~v tri ~~~ri ~ - 1 ~~~ ~ b~~-ir 

l -.ra s h iia.. o. a n, s; kc,> o n _s. . I) -.A, t; s o l.~ le 

v' i; ,I b?ji-.i(v' "J ). )o 4 d eve v ci. r F .r- i b l z 

hee.}i P thv ?..1. c:1,u,3 vi1-n i i-'.,;sui-np.limented 

v.'Ji tllX'.^ (; Om :,,/), kinetin /i 5:1J/) 

s ti C r- -o e( 3 h )c,%f t e r 43;-i d ca YI 1.n1 CC s 

r^3 t X tX s v | 

'o A a.,< t.Sr 4 

_.- 

ro tv ec d ;s! .%

20-3-k< d'.vs a'aies cultured on MS 

corntainio scuucr se (3r-S), nr> enerat ed 

s2oroPhytiJ.C L-cves in 35-53 a-s. Tporo,-,hytic callus was implanted noar 6 

months old' ibm subcut1 Cure callus 

regenerzting s,poronhytes; implanted callUb 

regenerated numercus ganmetophytes with sex 

organs. A.r'osporic garnetophytes were induced 

on MS containi'n- sucrose (I.2.) ohese 

gam,etophytes when transf-o-red to a fresh 

medium (MS) suppli.onnnted with kinetin 

(1m/1i) and sucro-se (4;v), apoaeaicus 

sporophytes orininated directly from 5-6 

lorge marginal cells of the gametophytes. 

Two slenuer rows oI xylem t..acheids wit L 

annular thickening- and aistinct stomata 

were present on apogarnously producoci leaves. 

REYNOLDS, THOMAS L. Department of Biology, 

University of North Carolina, Charlotte, NC 28223. 

- Cyanide-resistant respiration during spore 

germination of the fern, Sphaeropteris cooperi. 

During the first 96 h of culture, germinating spores 

of the fern Sphaeropteris. cooperi showed a gradual 

rise in respiratory activity to a maximum of 6.5 P1 02 

h-1..'mgl dry wt. This was followed by a transitory 

decline in rate, concluded by a second respiratory 

rise preceding the emergence of the rhizoid after 192 

h of culture. Oxygen uptake durlng the first 120 h of 

germination was insensitive to 1 mM KCN but was 

inhibited by 1mM salicylhydroxamic acid (SHAM); 

however, beyond this time cyanide showed increasing 

inhibitory effectiveness whereas SHAM became less 

effective. Regardless of.time of application, KCN had 

no effect on germination. Maximum inhibition of 

germination by SHAM was achieved if applied up to 120 

h after culture initiation, after which spores became 

insensitive to SHAM. Heat treatment (50 C for 90 min) 

during the cyanide-resistant phase of respiration (0 h 

-120 h) induced cyanide-sensitive respiration and 

completely inhibited spore germination. Elevated 

temperatures had little effect if applied during the 

cyanide-sensitive phase (beyond 120 h). Temperature 

inhibited spores regained their ability to germinate 

if maintained in culture until the cyanide-resistant 

pathway was restored and then subjected to a second 

photoinductive light treatment. These results suggest 

the presence and possible involvement of the cyanide- 

resistant alternative respiratory pathway during 

germination of Sphaeropteris cooperi spores. 

RICHARDSON, P.MICK. New York Botanical Garden, 

Bronx, New York 10458. - C-glycosylxanthones in 

th'e ferns. 

The occurrence of C-glycosylxanthones in ferns is 

reviewed. The 'compounds have a restricted distribution 

within four families: Hymenophyllaceae, Aspleniaceae 

sensu lato, Dava'l laceae and Marsi leaceae. 

They are known.to occur in 52 species In 16 genera. 

Reports of their occurrence have increased exponentially 

since the first report in 1962 and the compounds 

undoubt6dly remain uhdi'scovered in many ferns. 

The compounds appear fn to be little taxonomic value 

at higher level's becau-se- they have evolved Inadependently 

on 'severa'l occaszios. Theier mnejor value- is 

,pr6bably in the confirmation of al'lopolyploidy.- 

Pteridological Sectidn 95 

TAYLR, W. CARL*0, NEIL- T. LUEBKE, nd MARY B. SMITH. 

Botany Section, Milwaukee Public Maseum, Milwaukee, 

WI 53233. - Hybridizationas a soutce of taxonomic 

confui in 

The taxonomy o,f Isoetes in northeastern North America 

is confused bcOause hybridization obscures differences 

between the described taxa. Evidence for hybridiza- 

tion is found by studying spore germination, gameto- 

phyte development, and spor6phyte formation in labo- 

ratory cultures. Spores of twelve taxa from eighteen 

populations, collected in earljr fall, were vernalized 

in sterile, demineralized waier at 39C for 100 days 

and then incubated at 20QC with a12L:12D photoperiod. 

Within 50 days most cultures approadhed 100% germina- 

tion of megaspores. Taxa prodcicing polymorphic mega- 

spores either failed to germinate (I. X eatonii) or 

germinated at less than 1% (I. X gravesii and I. X 

heterospora). Gametophytes developing from polymor- 

phic spores bore either abnormal archegonia or no ar- 

chegonia. There was no evidence of apogamy in these 

cultures. Occasionally gametophytes with normal ar- 

chegonia were observed among the polymorphic mega- 

spores. These gametophytes produced sporophytes in 

the presence of functional spermatozoids. In nature, 

plants producing polymorphic spores usually are found 

in association with one or more taxa, suggesting the 

possibility of hybridization e.g., I. X foveolata with 

I. dodgei and I. tuckermanii. Morphologically defin- 

able species do exist in Isoetes and these are still 

best separated by megaspore size and ornamentation 

coupled with leaf characters. Chromosome counts re- 

veal different ploidy levels supporting species dis- 

tinctions and hybridization. Nearly all of the north- 

eastern North American species of Isoetes can be 

crossed in the laboratory but it appears that hybrid 

sterility isolates species in nature. 

WAGNER, FLORENCE S. Department of Botany, 

University of Michigan, Ann Arbor, MI 48109. 

- The Botrychium lanceolatum group in western 

North America. 

Outside of western North America there are known 

only six species of moonworts plus two hybrids. In 

western North America, we estimate that there are 

13 species plus five hybrids; 9 of the species are 

endemic. The B. lanceolatum group includes those 

moonworts with the pinnae oblong, lanceolate or 

linear, with central veins or costae. Botrychium 

hesperium is a distinct species, formerly treated 

as a variety of B. matricariifolium. It was con- 

fused with B. echo, which commonly grows with it, 

but differs from that species in approximately a 

dozen character states. Botrychium echo is known 

only from the southern Rockies, especially Colorado 

and Arizona, but B. hesperium ranges as far north 

as Alberta, Canada. A new species in this group is 

described that so far is known only in the north, 

ranging from Oregon to British Columbia and Saskatch- 

ewan. It differs from all of the other members of 

this group in a particular combination of charac- 

ters, including a unique pigmentation of the sporo- 

phore stalk, a relatively long sterile segment stalk, 

and distinctive structure of the sterile lamina, in- 

cluding the form of the margins and the pinnae, as 

well as the cuticle. Among the hybrids observed are 

combinations of B. hesperium X paradoxum, B. echo X 

minganense, and possibly the polyplo*d, B. pinnat. 

No true B- matric&ritifolium has been found in west- 

ern North America, nor true B. boreale. Except for 

these, ;all k1ow i of sot . b Botzy- 

chium are recorded there. i of tht endeiici ; 

long to the Luaria Gtoup, -two to the; Siplex Group, 

but four of- them belong to the Lanceolatui Group. 

The fourth group, cont&iniiig only ona species, B. 

paradxu, is also endemic to westerm North Aerica.

96 Systematic Section 

WHITTIER, DEAN P. Department of General 

Biology, Vanderbilt University, 

Nashville, Tennessee 37235. - 

Gameto-phytes of Lycpodium lucidulum in 

axenic culture. 

Spores of Lycopodium lucidulum Michx. were 

sown on a nutrient medium containing 

minerals, 0.5% sucrose, and o.6% agar, 

Gametophytes develop only in the cultures 

maintained in the dark. The white 

gametophytes are narrow, thickened, strap- 

shaped structures with dorsal and ventral 

surfaces. Externally, the meristem in the 

apical region appears as a groove under 

a dorsal lip of gametophyte tissue. This 

meristem extends along the margin of the 

Symposium: Biological Basis for Adaptations in 

Grasses 

i. .C i I ! L _ _ 

I, L t' 

. 

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-L i:i.1t:i_' 

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i-; L C L' 0 . . - L .... L; ; i_!w U 1, 'L ': CC i kt .v. i . 

; 

r 

b~~~~~~~~~~~~~~~ 

L .6.C 

* - i ) it t' .( tv _ i.;, !. ii ' t} i U -.jii 

.. I 

L- 

Z 010 L; L i L, i I 

'. i_ ;; t L - ( . * ; I5 t ;;L- L I..tt C 1. ;;' .LC i i ' 

It t :. t 

Lti .t1 t .j 

, 

SYSTEMATIC SECTION 

I-; lc~ 10 L 

t L i i L. C t . , L 

0,,L * i71 C i IC s;o ),) !A Li L 6t C, i'UL;U_i - . C i U- C) L C jLts 

L i ' %' x 

I . IJ C CL 

1~~~~s - !.l ('t( r,:

6, tetraploid levels have become widespread, and in 

Bambusoideae, Arundinoideae and Oryzeae x=12 has 

been the basis for higher multiples of this number. 

From x=6, aneuploid reduction has given x=5, and 

from x=12, came x=10, 9 and 8. Highest levels are 

14-ploid (in Calamagrostis) and 18-ploid (in 

Alopecurus, Bothriochloa and Saccharum). Percentage 

of polyploid species is between 65% and 75%, dep- 

endi'ng upon method of estimation. Neither the geo- 

phic nor climatic distribution differs significantly 

from that of diploids, except in isolated examples. 

Genera having medium sized to large chromosomes are 

as likely to evolve high polyploidy as those ha'ving 

smaller chromosomes. Annual diploids are less 

likely to evolve polyploids than perennials. A 

spectrum of cytogenetic conditions exists from auto- 

polyploidy to allopolyploidy: most species are 

intermediate between the extremes. Most autopoly- 

ploids are genetically heterozygous as a result of 

hybridization between differently adapted parental 

races. The results of an experiment lasting 40 

years show that autopolyploids, artificially produ-- 

ced, of Ehrharta erecta can persist under semi- 

natural conditions but are much less able to 

colonize new areas than their diploid progenitor. 

THOMASSON, JOSEPH R. Department of Biological 

Sciences, Fort Hays State University, Hays, KS 

67601-4099 

- Miocene grasses from central North America. 

Species of Berriochloa, Paleoeriocoma, Nassella, 

Archaeoleersia, Panicum and Graminophyllum (Gramineae) 

collected from Miocene strata in central North 

America were examined and compared with modern taxa. 

With the exception of Graminophyllum, an organ genus 

of grass leaves, the fossil genera are preserved as 

the remains of the reproductive bracts (husks) which 

enclosed the grain. 

Berriochloa, the oldest known genus, first appears 

in early Miocene strata where it has a rigid cylin- 

drical husk and an elongated, pointed callus. These 

features probably evolved primarily as adaptions to 

grazing animals and insects. Rigid husks found on 

other fossil genera were a similar adaptive mechanism. 

From the early Miocene forms of Berriochloa evolved 

two mid-late Miocene lineages. In one lineage the 

husk remained cylindrical while in the other lineage 

the husk became prominently inflated. Within both 

lineages the surfaces of the husks were variously 

smooth to densely covered with hooks and/or hairs. 

Both lineages retained the elongated, pointed callus. 

The lineage of inflated forms probably evolved in 

response to ingestion by grazing herbivores. Related 

living taxa such as Stipa and Piptochaetium show ad- 

aptive mechanisms similar to those of the fossils, 

although evolutionary changes such as the loss of the 

elongated callus has occurred in some forms. 

Fossils of Graminophyllum collected in association 

with the fossil grass husks appear deeply ribbed 

and furrowed. This is caused by rows of well devel- 

oped bulliform cells alternating with raised costal 

areas. Many of the fossil leaves collected show 

involution which indicates that this adaptive mech- 

anism in the grasses dates at least to the Miocene. 

Symposium: Cleistogamy: Its Ecology and 

Evolution 

INTRODUCTION 

Cleistogamy is widespread in its occurrence and di- 

verse in its biological significance among angio- 

Systematic Section 97 

sperms. It is known in primarily herbaceous taxa from 

29 families. Its expression may produce marked mor- 

phological and developmental differences from the evo- 

lutionarily primitive chasmogamous condition. It may 

be important in reducing animal predation of seeds and 

in altering their size, presentation, susceptibility 

to fire, dispersibility and germinability. 

The primary objective of this symposium is the examin- 

ation of the origins and types of cleistogamy through 

an integration of ecological and systematic data via 

a bridge of evolutionary theory. 

Organized by J.A. Quinn, Rutgers University, Pis- 

cataway, NJ and C.S. Campbell, University of Maine, 

Orono, ME. 

CAMPBELL, CHRISTOPHER S.* and JAMES A. QUINN*. 

Department of Botany and Plant Pathology, University 

of Maine, Orono, ME 04469 and Department of 

Biological Sciences, Rutgers University, 

Piscataway, NJ 08854. - Relationships between the 

types of cleistogamy in grasses- and variation in 

reproductive structures, habitats, and lifehistory 

strategies. 

Cleistogamy has been reported from 321 species and 

82 genera of grasses and is therefore far more common 

than in any other angiosperm family. It is also 

probably expressed in a greater diversity of ways in 

the Gramineae. We recognize 4 types of cleistogamy 

(CL) in grasses based on the source of confinement 

of the flowers: spikelets, upper stem sheaths, lowermost 

stem sheaths (cleistogenes), and the soil for 

subterranean flowers (rhizanthogenes). With respect 

to the chasmogamous counterparts of the same individual 

or species, these types are associated with 

different degrees of dimorphism of the floral and 

spikelet parts and of the size, dispersibility, and 

germinability of the seeds. Species showing CL are 

predominantly (79%) tufted or cespitose, and twice 

as many perennials as annuals have been reported to 

show at least one type of CL. Altllough about 60% of 

the species with CL are colonizers of disturbed, 

successional habitats, there are other habitats and/ 

or selective pressures that can be linked to the 

development of the various CL types. Almost 2/3 of 

the non-ruderal CL perennials are "stress-tolerators", 

occurring in shallow or sandy soils of low 

moisture-holding capacity and/or in environments of 

low and unpredictable rainfall. These species commonly 

show the upper stem sheath type of CL. Selective 

advantages for cleistogenes and rhizanthogenes 

may include protection from herbivory, environmental 

extremes, or fire, and the placement of seeds in the 

microhabitat occupied by the mother plant. 

CLAY, KEITII. Department of Botany, 

University of Texas, Austin, TX 78712. 

- Genetic and demographic aspects of 

cleistogamy. 

Cleistogamy results in obligate self-ferti- 

lization. Genetic differences between pro- 

geny from chasmogamous (CH) and cleistogam- 

ous (CL) flowfers depend on the rate of out- 

crossing of CII flowers and the amount of 

genetic variance present in the population. 

At the family level CL progeny should be 

less variable than their CII sibs, but more 

variable at the population level. Genetic 

variance is maximum wfhen the population con- 

sists of pure inbred lines. Experiments con-


ducted with the grass Danthonia spicata 

shoved CL progeny were significantly less 

variable for 14 quantitative traits compared 

to CH progeny from the same plant. The rela- 

tionship between plant fitness and its 

reproductive origin (CH or CL flowers) may 

be influenced by non-genetic factors such as 

seed size, germination requirements, and 

dispersal differences precluding broad gen- 

eralizations about this relationship. A sur- 

vey of the literature provides cases of CL 

progeny being superior, inferior, or the 

same as CH progeny from a variety of species. 

Wfhen non-genetic differences between CH and 

CL progeny were experimentally controlled in 

D. spicata the CH progeny had slightly high- 

er survival and reproductive rates (but non- 

significant) compared to CL progeny. The 

variance in fitness, as opposed to mean fit- 

ness, was significantly higher for CII pro- 

geny. Thus, in D. spicata, the major genetic 

consequences of cleistogamy and chasmogamy 

are on the variance rather than the mean. 

LORD, ELIZABETH. Department of Botany and Plant 

Sciences, University of California, Riverside, 

CA 92521. - Comparative study of cleistogamous 

and chasmogamous flowers. 

In cleistogamous species, two types of hermaphro- 

ditic, self-compatible flowers are borne by an in- 

dividual. The closed or cleistogamous (CL) flowers 

set seed by self-fertilization, while the open or 

chasmogamous flowers achieve anthesis and may out- 

cross. At least 58 families contain such species 

for which real structural differences in the two 

floral forms have been documented. The common de- 

nominators are reduction in, at least, the CL an- 

droecium and corolla as well as a lack of anthesis. 

Shape modifications may occur in all the CL organs. 

Pollen number is always reduced in the CL flower 

and often pollen size. Differences in pollen ultra- 

structure exist in the species studied though little 

work has been done on pollen-stigma interaction. 

Germination of CL pollen occurs in the anther with 

the tubes emerging from an open stomium or penetrat- 

ing the wall of an unopened anther. Stigmatic 

receptivity is precocious in the CL flower and close 

proximity to the anthers ensures pollination in the 

closed bud. Ontogenetic study has demonstrated 

that divergence in form occurs early in development, 

always prior to anther differentiation. Precocious 

anther differentiation is followed by modifications 

in corolla form. Dissociations of parts of organs 

result in new shapes being produced. Ontogenetic 

shifts in floral form occur during inflorescence 

development in the annuals studied. Intermediate 

forms exist primarily in the CL population. Preco- 

cious development and function characterize the 

CL flower. Utilizing data on form and size changes 

over time, we have devised models to describe the 

ontogeny and phylogeny of the CL from the CH form. 

SCHOEN*, DANIEL J. and LLOYD, DAVID G. Department 

University of Canterbury, Christchurch, New Zealand 

- Models for the evolution of cleistogamy and 

heteromorphic fruits. 

Models for the evolution of cleistogamy are de- 

scribed. The "basic" model takes into account the 

economy and certainty of cleistogamous fertilization, 

and the inability of cleistogamous flowers to con- 

tribute pollen to the outcrossed pollen pool. Coin- 

plete cleistogamous self-pollination is favored when 

allocation to maternal function, fertilization rate, 

and viability of progeny are sufficiently greater 

for the cleistogamous compared with the chasmogamous 

component, and when resources spent on ancillary 

structures in cleistogamous flowers, the cleistoga- 

mous seed costs, and inbreeding depression are low. 

The "complex habitat" model extends the basic model 

to situations in which success of reproduction by 

cleistogamy or chasmogamy varies according to the 

environment of the parent plant. In this situation, 

reproduction by both cleistogamy and chasmogamy may 

be favored. A "near and far" dispersal model ad- 

dresses the question of dual modes of dispersal which 

often occur in cleistogamous plants. Dual modes of 

dispersal may be favored if a narrowly dispersed seed 

type is more successful at establishing in the sites 

located within its dispersal range, compared with a 

second, more widely dispersed seed type produced by 

the same plant. Predictions of the models are dis- 

cussed with respect to relevant data, and suggestions 

are made for the apparent rarity of cleistogamy as a 

mode of self-pollination. 

*PRESENT ADDRESS: Department of Botany, University 

of Georgia, Athens, GA 30602. 

WALLER, DONALD M. Department of Botany. 

University of Wisconsin, Madison, WI 53706. 

- Plant size, flower development time, and their 

implications for the expression of cleistogamy. 

Many cleistogamous (CL) plants adjust their level 

of investment in CL flowers in response to variable 

environmental conditions. A review of these 

patterns reveals that when CL is facultative, 

larger plants or those in better physiological 

condition outcross the most. For selection to 

favor such responsiveness, either the cost of 

chasmogamy (CH) or its benefit should change 

consistently with plant size. Studies on 

inbreeding depression usually demonstrate a 

benefit to outcrossing, but this benefit is not 

reliably density dependent. Turning to costs, CL 

seeds are known to be significantly cheaper than 

CH seeds, both in terms of energy and the time 

they take to develop. If small plants or those 

under physiological stress take longer to produce 

a seed, they would have less effective time to 

reproduce. This would result in strong selection 

for efficient prior self-fertilization (i.e. CL) 

in small or stressed plants (or independent parts 

of plants). This relative time hypothesis could 

therefore account simultaneously for time-, size-, 

and energy-dependent patterns of chasmogamy. 

Symposium: Generic Concepts in the 

Compositae 

INTRODUCTION 

Recent treatments of the Compositae, especially in 

the large genera Eupatorium and Senecio, have brought 

forward the issue of "large natural genera" vs. 

"small natural genera." The symposium will attempt 

to evaluate the whys and wherefores, wisdom, need, 

pragmatics and otherwise of such varying treatments. 

While no concensus will be sought, an effort will be 

made to look into the philosophical concepts and 

methodological approaches which occasion such varying 

treatments so as to ascertain if there might not be, 

afterall, some meaningful guidelines for generic recogn 

i ti ons . 

Organized by Bill1ie L . Turner, Universi ty of Texas, 

Austin, TX.

Barkley, T. M. Herbarium, Division of Biology, 

Kansas State University, Manhattan, Kansas 66506. 

- Generic concept in the Senecioneae. 

Since the time of Geo. Benthan the traditional view 

of the Senecioneae has been that of one huge genus 

(Senecio) plus numerouis segregate genera of varying 

degrees of distinctiveness, plus a few entities of 

uncertain affinities. Data have accumulated to sup- 

port the exclusion of some genera from the tribe 

(e.g. Arnica, Liabun, Munnozia, Schistocarp,a, etc.) 

and to tease botanists about the circumscriptions 

and affinities of others. Senecio, s.l., incorpor- 

ates several semi-distinctive natural assemblages 

which have been treated usually as sections or sub- 

genera. The naturalness of these assemblages is 

generally acknowledged, as is the fact that the 

boundaries separating them are imprecise by whatever 

suites of characters are used to measure them. In 

several recent studies many segregate genera have 

been recognized, often with the circumscriptions de- 

rived from selected representative species. It is 

yet unclear that the recognition of numerous segre- 

gate genera provides a better taxonomy than treating 

the variation patterns as infrageneric taxa. A re- 

spectable case can be made for maintaining Senecio 

as a broad concept, at least until revisionary 

studies at the species level are carried out and the 

results subjected to critical analyses. 

BOLICK, MARGARET R. Division of Botany, 

University of Nebraska State Museum, Lincoln, NE 

68588-0514. - Hennigian cladistics and the generic 

concept in Iva (Ambrosiinae, Heliantheae). 

In 1960, Jackson divided Iva into three sections: 

Iva, Linearbractea, and Cyclachaena. A reanalysis 

of Iva using the precepts of Hennigian cladistics 

reveals 1) that there are no synapomorphies connecting 

sections Iva and Linearbractea to section 

Cyclachaena; 2) that there are no synapomorphies 

connecting the species within Cyclachaena; and 3) 

that the species of Iva and Linearbractea are unified 

by three synapomorphies. The analysis also 

suggests that the five species of Cyclachaena are 

more closely related to other genera in the subtribe 

than they are to Iva and Linearbractea. The resulting 

classification recognizes Iva and 

Linearbractea as Iva (sensu stricto) and the five 

species of Cyclachaena as separate monotypic genera. 

CARR, GERALD D. Departnt of Botany, University 

of Hawaii, 3190 Maile Way, Honolulu, HI 96822. 

- Habital variation in the Hawaiian Madiinae 

(Heliantheae) and its relevance to generic 

concepts in the Ccrpositae. 

The Hawaiian Madiinae caoprises monocarpic rosette 

shrubs, mat-forming subshrubs, cushion plants, small 

shrubs, large shrubs, trees, and even a liana. 

Habitats occupied by nEmbers of the alliance range 

from dry scrub receiving about 40 cm of precipitation 

annually to sumnit bogs with an annual precipitation 

exceeding 1250 cm. In spite of enornous 

habital and habitat differences and even chromosomal 

differentiation between the various forms, a nyriad 

of natural and artificial hybrids denonstrates the 

genetic cohesiveness of the group. Thus, the 

Hawaiian Madiinae constitutes what is probably the 

most spectacular exaxrple of adaptive radiation in 

plants. Traditionally, four genera (Argyroxiphium, 

Dubautia, Railliardia, and Wilkesia) have been 

recognized in this group. The biosystematic 


evidence and tfie overall pattern of variation 

support the rrmrger of Dubautia and Railliardia. 

However, even in the narrow sense Dubautia includes 

a cushion plant, shrubs, trees, and a liana. Thus, 

in this instance habital variation is considered to 

be of little or no value in the circumscription of 

genera. 

FUNK, VICKI A. Department of Botany, Smithsonian 

Institution, Washington, D. C. 20560. - Cladistics 

and generic concepts in the Compositae. 

Taxonomy classes are often taught that classification 

involves grouping and ranking. In reality we are 

actually concerned with grouping on two levels: the 

grouping of individuals (into species), and the group- 

ing of 'groups of individuals.' There are, therefore, 

only two categories, species and groups of species. 

The importance of this concept lies in a logical 

extension of it, that the various levels at which the 

'groups of species' are recognized are not of major 

concern to cladists. In discussing generic concepts 

we begin with a cladogram that has species for termi- 

nal taxa and ask - How do we convert this into genera, 

sub-tribes, etc.? To cladists, the cladogram is the 

classification, and the guideline for turning it into 

a hierarchy is as follows: while maximizing informa- 

tion, strive to minimize novelty and redundancy. Or, 

develop a classification that will retain monophyletic 

groups but will disrupt the present classification as 

little as possible and create the fewest monotypic 

taxa. Some Examples - Although redundancy and disrup- 

tion are minimized, information is not maximized by 

the use of "core genera" (e.g., Vernonia Schreb.) over 

smaller monophyletic groups. However, the segregates 

must be defined by synapomorphies and the parent group 

cannot be left paraphyletic as has happened in Stevia 

Cav. and Senecio L. Placing the genus Montanoa Cerv. 

in a subtribe by itself is redundant, but placing it 

in any other subtribe destroys the naturalness of the 

latter. Maintaining artificial genera (e.g., Culci- 

tium H. & B.) is indefensible because they imply false 

information. Classifications giving consistent infor- 

mation cannot be achieved by whim. The cladistic 

approach gives us well-reasoned guidelines for evalua- 

ting and comparing classifications and can help in 

deciding on when to retain the existing genera and 

when to describe new ones. 

GAGE, DOUGLAS 

A. Department of Botany, 

University of Texas, Austin, TX 78712. - Chemical 

features as generic criteria in the Eupatorieae. 

To date over 250 species in the Eupatorieae have 

been chemically studied. The majority of this work 

has focused on terpenoid constituents. The results 

thus far depict the tribe as chemically heterogeneous, 

producing a large number of diverse sesquiterpenes, 

diterpenes, as well as thymol and benzofuran deriva- 

tives. When this chemical diversity is examined in 

relation to the traditional large genera recognized 

in the Eupatorieae (e.gj., Eupatorium, Stevia, Mikania) 

no clear chemical boundries are found.In comparison, 

mixed results are obtained in relating terpenoid 

chemistry to the limits of the more narrowly defined 

genera of a recent reorganization of the tribe's 

classification. While some of the smaller genera 

appear chemically distinct, others are chemically 

diverse, and still others are chemically indistinguish 

-able from affiliated genera. The larger genera 

recognized in this treatment (e.g., Ageratina, 

Chromolaena ) tend to be heterogeneous in their 

terpenoid chemistry.


JONES, ALMUT G. Department of Botany, University 

of Illinois, Urbana, IL 61801-3793.-- Chromosomal 

features as generic criteria in the Astereae. 

In their tribal characteristics the Astereae are well 

defined, but determination of generic limits within 

the tribe has been subject of much dispute. Several 

examples in Astereae may serve to address three basic 

questions concerning usefulness of chromosome features 

in delimiting genera: (1) What do chromosome numbers 

per se tell us? (2) Can genera with more than one 

mode of basic chromosome number be regarded an monophyletic? 

(3) Are chromosomal features correlated 

with gross morphological characteristics that will allow 

construction of useful classifications? The first 

question immediately leads to another:can we assume 

that the condition of, e.g., x = 9 is homologous for 

all taxa sharing this character state? Many, if not 

most, genera in the tribe are represented by polyploid 

series. While some taxa may have primitively "x = 9", 

there is indication that others may have secondarily 

acquired that number, via allopolyploidy from n = 4+5 

or via aneutetraploidy from n = 10-1. The second 

question has been raised repeatedly for such genera as 

Aster, Astranthium, Brachycome, Ha l a us, Heterotheca, 

and Machaeranthera all sens. lat. . Persuasive 

arguments can be presented for answers on both sides 

of the question. The true situation may be that some 

genera are monobasic, while others have more than one 

basic chromosome number. The decision for one or the 

other will (or should) be linked to an answer for the 

third question. Chromosomal characteristics undeniably 

are of fundamental importance to an understanding of 

interspecific relationships, but unless these microscopic 

features are correlated with distinct gross 

morphological characteristics, they probably are not 

useful in the determination of generic limits. On the 

other hand, such correlations usually do exist at the 

subgeneric or sectional levels. 

LANE, MEREDITH A. Department of Environmental, 

Population and Organismic Biology, University of 

Colorado, Boulder, CO 80309.--Ultrastructural 

features as generic criteria. 

The advantages of grater resolution and depth of 

field provided by the scanning electron versus the 

light microscope have led to both a re-evaluation of 

traditional microcharacters and discovery of "new" 

characters, particularly of surfaces, not easily observed 

by other means. Comparative studies of these 

characters in taxa of Compositae have shown that they 

are taxonomically useful, but that they are neither 

more nor less valuable as a means of generic delimitation 

than are gross or micromorphological 

is true of taxonomic data from any source, 

ones. 

it is 

As 

the 

consistent occurrence of one or more ultrastructural 

feature(s) as a part of a suite of correlated characters 

that provides sufficient information on which to 

base systematic decisions. Wihtin this context, it is 

the "new" characters that prove most useful: the 

chances of finding correlated character suites rises 

with 

bers 

the number of characters observed. Among memof 

the subtribe Solidaginae (Astereae), corolla 

epidermal 

characters 

cell features may be consistent with other 

that differentiate related groups of taxa. 

However, because studies of infraspecific variation 

in ul tras tructures are rare ( due to the relative expense 

of SEM), these characters should be employed 

with caution and in conjunction with numerous others 

in making taxonomic decisions at the generic (or any 

other) rank. 

POWELL, A. MICHAEL. Department of Biology, 

Sul Ross State University, Alpine, TX 79830. 

Crossing data as generic criteria in the 

Asteraceae. 

Crossing data have long been used to help deter- 

mine the position of species whose generic status 

is questionable, to help define subgeneric taxa, to 

merge genera, and, in a limited number of studies, 

to help establish generic boundaries, Previous 

studies in the subtribes Peritylinae and Flaveriinae 

(Helenieae) have demonstrated that crossing data 

can be employed as a major approach in delimiting 

generic entities and in establishing relationships 

between genera. In fact, in the above taxa cross- 

ing data proved to be more useful at the genus 

level than at the species level. Such crossing 

tests can be employed at optimum only if it is 

possible to produce hybrids between most of the 

species in the putative genera concerned. It does 

appear that it is often possible to obtain compre- 

hensive data from artificial interspecific hybrid- 

izations, especially when allopatric perennial taxa 

are involved. The interpretation of crossing data 

may present problems because variable inter- 

fertility values in different taxa are to be ex- 

pected, and independent taxonomic judgements must 

be made in context with information from other 

approaches. In the tribe Eupatorieae, where 

extensive generic reorganization has been proposed 

in recent years, hybridization tests may be possi- 

ble in some groups (Carterothamnus X Hofmeisteria; 

Koanophyllon X Pseudokyrsteniopsis) but not in 

others (Brickellia). 

ROBINSON, HAROLD* 

and KING, R. M.,*Department of 

Botany, Smithsonian Institution, Washington, D.C., 

20560. - Generic concept in the tribe Eupatorieae. 

Traditional genera of the tribe, based heavily on 

pappus and anther appendage, prove totally indefensi- 

ble, having been subjected to piecemeal alterations 

by all significant workers since Linnaeus, and being 

useless for comparison with any new evidence. The 

total tribal revision of the present authors, based 

on structure, cytology, geography and chemistry, has 

180 genera in 18 subtribes. What was Eupatorium has 

been distributed among 11 of the subtribes, and is 

intermixed with elements of other traditional genera. 

Eupatorium (44 sp.,X=10) remains a distinct Arcto- 

Tertiary genus. Mikania (410 sp.,X=18-20), Stevia 

(229 sp.,X=11,12), Liatris (42 sp.,X=10), and Brick- 

ellia (96 sp.,X=9) have minor changes. Ageratum (40 

sp,X=10) is broadened to include epappose species. 

Ageratina (230 sp.,X=17), the epiphytic Neomirandea 

(25 sp.,X=17,20), Chromolaena (165 sp.),Fleischmannia 

(79 sp.),Koanophyllon (115 sp.)(all X=l0)are named or 

restructured to include much that was in Eupatorium. 

The subtribe Gyptidinae, mostly of eastern Brazil, is 

one of two most complex, but has many particularly 

distinct genera such as Campuloclinium (14 sp.), 

Trichogonia (30 sp.), Lasiolaena (5 sp.) and Agrian- 

thus (6 sp.)(all X=10). Most problems of numerous 

small genera and hybridization involve the largest 

subtribe Critoniinae of the moist Neotropics, but 

tests of many individual genera has reenforced their 

distinct status, i.e., Critonia (38 sp.),Ophryosporus 

(37 sp.), Fleischmanniopsis (5 sp.) and Neocabreria 

(5 sp.)(all X=10). The reclassification reflects the 

fact that the tribe is neither simple nor comparative- 

ly derived in the family.

SCOTT, RANDALL W. and SCOTT D. SUNDBERG. Department 

of Botany, University of Texas at Austin, 

Austin, TX. 78712 

-licrocharacters as Generic Criteria. 

A study of microcharacters (as viewed under the 

compound microscope) in the Eupatorieae and Astereae 

(Compositae) was undertaken in order to evaluate 

their reliability as taxonomic markers. Character 

states of various microcharacters are widely 

distributed within the tribes Astereae arld 

Eupatorieae. Correlations between microcharacters 

and yet other characters were used in order to 

evaluate their applicability in delimiting genera. 

A high degree of microcharacter correlation with 

yet other characters was found in some species 

groups suggesting that they are useful and consistent 

markers among such taxa, whereas in other groups 

they may be of little value. 

Symposium: Phylogenetic Systematics and 

Speciation 

INTRODUCTION 

Usually workers in the study of speciation operate by 

creating (or adopting existing) historical explana- 

tions for their observations. Distributions are di- 

vided, barriers erected and various degrees of repro- 

ductive isolation are invoked. Observations from 

other organisms that can be explained by the same 

scenarios are gathered together and a 'mode' is born. 

This symposium is an attempt to treat the study of 

speciation in a more empirical manner. Various 'modes 

of speciation' and species definitions are tested 

against the patterns of relationship and distribution 

of taxa in birds, fish, cacti, composites and mosses. 

Using this method for examining speciation may allow 

us to differentiate between refuted and corroborated 

'modes' and definitions in the various groups of taxa 

examined. 

In the Compositae several groups have been studied 

enough to investigate speciation (i.e., cladograms 

are available). Close examination of the distribution 

of groups of sister species in ten Latin American 

genera in the flowering plant family Compositae (six 

genera in the Liabeae; one in the Senecioneae; three 

in the Heliantheae) indicates that a hypothesis of 

allopatric speciation is refuted least often. In 

addition, area cladograms for the genera (cladograms 

that indicate the distribution of the terminal taxa) 

indicate that speciation as a result of vicariance 

can be corroborated as well as speciation as a result 

of dispersal. Finally, the only useful definition 

for composite species is one of morphological unique- 

ness. 

Organized by Vicki A. Funk, Smithsonian Institution, 

Washington, D.C. 

DARROWCLOUGH, GEORGE F. Department of Ornithology, 

American Museum of Natural History, NY, NY 10024. 

- Speciation in western North American birds. 

In the 50 years since the development of the new 

synthesis, parapatric avian taxa in western N. A. 

have been studied intensively in a search for hybrid 

zones or other evidence of interbreeding. Such 

evidence has been used to relegate distinct evolutionary 

lineages to subspecies status, in accordance 

with the tenets of the Biological Species Concept 

(BSC). However, when the results of these studies are 

used to examine critically the reasonableness of the 

BSC, it is found that the concept does not make good 

evolutionary, phylogenetic, or population genetic 


sense for birds, because such species taxa may 

represent more than one evolutionary unit and 

terminal taxon. This inconsistency has led to ambi- 

guity in the examination and interpretation of modes 

and patterns of avian speciation. When the data are 

interpreted in terms of an evolutionary or phylo- 

genetic species concept, several empirical general- 

izations emerge. First, sympatric and parapatric 

modes of speciation are not consistent with the 

geographical distributions and with what is known 

about the population ecology of these organisms. 

Second, it does not appear that the differences in 

plumage patterns ccmmonly found between hybridizing 

sister taxa function as reproductive isolating 

mechanisms because the birds, themselves, do not use 

them for that purpose. 

CHURCHILL, STEVEN P. Department of Botany, 

University of Kansas, Lawrence, KS 66045. - 

Patterns and processes in moss speciation. 

The connecting link between systematics and evolution 

is phylogeny and the basic phylogenetic unit is the 

species. As such, species, the most fundamental 

hypothesis in systematics, must be monophyletic and 

exhibit some degree of apomorphy within the context 

of what is known about the biology of the taxon, in 

this case Musci. No species concept has been prevalent 

in moss systematics, which may be an asset-, but 

future studies must address this subject. Previous 

considerations of moss speciation have approached the 

subject from one of two perspectives. Either known 

or assumed mechanisms have been reviewed or patterns 

based solely on extant distributions have been derived 

through a basically phenetic approach. Several 

processes have been defined: at the chromosomal 

level, polyploidy and aneuploidy are apparently 

frequent; particularly significant is the suggestion 

that half or more of the taxa examined at the gametophytic 

level are functionally diploid; finally, 

apogamy, apospory, and diplospory are thought to be 

frequent. While mechanisms can be described for any 

single event, we shall never know if the result is 

unique or general unless we can compare it to other 

events within and between monophyletic lineages. At 

present very few systematic studies have produced 

testable phylogenetic patterns. We may best study 

speciation, those genetic and epigenetic processes 

involved in the production of taxa, if we know the 

phylogeny of the species we study. The need now is 

to make predictions of processes based on observed 

patterns, and predictions of patterns based on detected 

processes which would provide an independent 

test of the value of each in elucidating evolutionary 

history. 

CRACRAFT, 

JOEL. Division of Birds, Field Museum of 

Natural History, Chicago, IL. 60605. 

-Patterns of speciation in South American birds. 

A phylogenetic hypothesis for the differentiated 

taxa (=species) of a group also defines a biogeogra- 

phic pattern. Congruence in such patterns implies a 

common history and permits us to identify those 

aspects of history which are unique to each group. 

Approximately 35-40 areas of endemism can be 

described for the neotropical avifauna. Cladistic 

hypotheses for more than 30 genera and species-groups 

demonstrate a remarkable degree of congruence in 

their biogeographic patterns. The following implicat- 

ions will be discussed: (a) avian speciation on 

continents is predominately by vicariance rather than 

by founder effects, (b) avian speciation patterns in


the neotropics cannot be explained by the prevailing 

model of Pleistocene "refugia," (c) many areas of 

endemism--and their biotas--are older than the 

Pleistocene, and (d) the rate change in lithospheric 

complexity constitutes a deterministic causal 

explanation for spatial and temporal variation in 

speciation rates and patterns of species diversity. 

GIBSON, ARTIIUR C. Department of Biology, 

University of California, Los Angeles, CA 90024. 

-Plant disjunctions in arid and semiarid North 

America--a search for multi-area cladograms. 

Current reconstructions of the floristic history of 

arid and semiarid North America are primarily based 

on patterns of extant plant ranges and infrageneric 

disjunctions. Unfortunately, because phylogenetic 

relationships of Mexican species are poorly under- 

stood, much of this reconstruction has been of the 

narrative type. In fact, to date most systematic 

treatments of Mexican taxa have not hypothesized the 

phylogenetic relationsh-ips of each species but have 

instead lumped taxa into series, sections, and sub- 

genera and then discussed the interrelationships of 

these higher taxa. To begin an earnest attempt to 

uncover coincident phylogenetic and areal patterns, 

one can analyze the phylogenetic model of Mexican 

columnar cacti (tribe Pachycereeae), which occur in 

many interesting dry forests and desertscrubs, have 

noteworthy patterns of endemism and disjunction, and 

have a recent phylogenetic model of the species based 

on synapomorphies. In these cacti, the clades 

radiate from southern Mexico in various directions, 

so that the northern deserticolous taxa are derived 

versions of species found in the nearby dry tropical 

forests to the south. Genera of trees and shrubs 

in other families that co-occur with columnar cacti 

are analyzed with Pachycereeae to identify any 

recurrent patterns of disjunction or speciation and 

possible multi-area cladograms. An overview of other 

disjunction patterns in arid and semiarid Jlexico is 

iade to determine whether plant disjunctions can be 

used in a rigorous way to elucidate the climatic and 

vegetational history of Mexifto and the arid south- 

wqestern United States. 


CLARK, CURTIS. Biological Sciences, 

California State Polytechnic University, 

Pomona CA 91768. - Herbarium label-writing 

on a "mainframe" computer. 

Most of the drudgery of writing herbarium 

labels is in retyping information that does 

not change from one label to the next, and 

typing duplicate labels. The ability of 

computers to store information can alleviate 

much of this. Full-screen word-processing 

systems are designed for such use, but not 

all herbaria have these available. Our sys- 

tem uses instead a "mainframe" computer, of 

the type available on most college campuses. 

An interactive BASIC-language program takes 

input from a worker at a terminal and writes 

it on a file which is then sent to a word- 

processing program of the RUNOFF type for 

final manipulation into herbarium labels. 

We havYe found that a "user-friendly" program 

must have certain features: (1) a HELP com- 

mand, (2) a standard order for inputting 

information, but the ability to deviate from 

it at any time, (3) the ability to proof the 

information at any time, and (4) the ability 

to selectively erase information at any 

time. Our program has been used success- 

fully in a one-quarter beginning plant tax- 

onomy course. It prints labels in a stan- 

dard format, which can be changed by alter- 

ing one section of the program. Listings 

of the program will be available. 

JOTCHAM, J.R. and D.W. SMITH. Department 

of Botany & Genetics, University of 

Guelph, Guelph, Ontario, Canada. NIG 2W1 

-A numerical analysis of Ericaceae. 

Numerical analyses were applied'to a pre- 

viously published data set of 60 characters 

for 52 genera of Ericaceae (Stevens, 1971). 

The classification methods applied included 

polythetic agglomerative and polythetic 

divisive (2-way indicator species analysis) 

procedures. The ordination methods included 

principal components analysis and detrended 

correspondence analysis. The resulting 

clusters were tested using multiple dis- 

criminant analysis. All analyses were per- 

formed with commercially available software. 

The results did not completely coincide, 

but they essentially agree with Stevens' 

treatment of the family, especially at the 

subfamily level. The Pyroloideae and Mono- 

tropoideae are usually well within the 

family boundries as defined, but the Witt- 

steinioideae are a definite outlier with 

this data set. The ordination diagrams did 

not show clearly disjunct clusters in most 

cases, but the genera of any one subfamily 

tended to group together. 

MACDONALD, S. ELLEN and C.C. CHINNAPPA. Department 

of Biology, University of Calgary, Calgary, Alberta 

Canada. T2N 1N4 - Morphological variation within 

an isolated population of Stellaria longipes Goldie 

(Caryophyllaceae) on the Athabasca sand7dlunes. 

Stellaria arenicola Raup is considered to be a 

species within the S. longipes complex) endemic to 

the Athabasca sand dunes in northern Saskatchewan. 

This unique area is characterized by shifting sands, 

unusual moisture conditions and intense insolation. 

These isolated populations share a combination of 

morphological characters which are distinct from 

other members of the S. longipes complex. This widely 

distributed complex is known to be plastic with 

respect to: number of flowers, habit, length of stem, 

leaf shape and pigmentation. The arenicola type 

is identified by its spreading habit and large 

yellow capsules with reflexed teeth. Twenty subpopulations 

of S. longi (including the arenicola 

type) were studied in t e Thomson Bay dune field. 

Morphological features including habit, capsule 

characteristics, stem length, pigmentation, number of 

flowers, leaf shape and size,and flower size and sex 

were characterized in each population. A gradation 

from the longipes form to the typical arenicola form 

is evident.-iTere is great variability in capsule 

col or and s ize . Envi ronmental1 parameters i ncl udi ng 

shading, sand accumulation, soil water potential and 

other soil characteristics (nutrients, organic matter 

and particle size) were determined for each site. 

The association of morphological features with microhabitat 

characteristics will be presented.

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ALLEN, GERALDINE A. Department of Biology, 

University of Victoria, Victoria, B. C., Canada 

V8W 2Y2. - The hybrid origin of Aster bernardinus 

(As teraceae). 

Aster bernardinus is endemic to the Peninsular and 

southern Transverse Ranges of southern California, 

and las the polyploid chromosome number of n = 18 

throughout its range. Chromosome base numbers in 

Aster include 5, 7, 8, 9 and 13 (previous work has 

shown the base number 13 to be the result of 

combining 5 and 8). The reports of n = 18 for 

A. bernardinus suggest a base number of x = 9. 

However, this species shows little resemblance to 

other species with this base number, but is 

apparently an amphiploid derived from backcrossing 

between the Great Basin species A. ascendens (x = 

13) and one of its parents, A. falcatus x = 5). 

Multivariate analyses using 28 morphological 

characters measured on specimens of known chromosome 

number showed that A. bernardinus closely resembles 

A. ascendens, but has some characteristics of A. 

falcatus'. The karyotype of A. bernardinus incTudes 

two pairs of large chromosomes with almost terminal 

nucleolar organizer regions; it combines the 

features of the karyotypes of A. ascendens and 

A. falcatus. The two species A. ascendens and 

A. bernardinus form a bridge between two well-marked 

subgenera of the genus Aster. 

ARMBRUSTER, W. SCOTT, Division of Life Sciences, 

University of Alaska, Fairbanks, AK 99701 - The 

Evolution and Chemistry of Pollinator Rewards in 

the Genus Dalechampia (Euphorbiaceae 

A parsimonious model of the phylogenetic relationships 

between species of Dalechampia was constructed using 

characters of inflorescence morphology. The polarity 

of character states was established using out-group 

comparisons with the Plukenetieae, coupled with 

analysis of character trends and vestigial structures. 

When data from pollination studies are incorporated into 

the phylogenetic model, they indicate that the earliest 

pollinator reward offered by members of the genus was 

probably pollen; pollination was probably effected by 

pollen-collecting bees. From this stock evolved 

species that secrete triterpenoid resins as pollinator 

rewards; the resins were (are) collected by female bees 

of the Megachilidae, Euglossini and/or Meliponini. 

More recently, from d i fferent ancestral groups of res i n- 

secreting species there have arisen two independent 

lines of species that have switched to secretion of 

monoterpene volatiles as pollinator rewards; pollination 

in these species is effected by male euglossine 

bees. 

ATKINS, RILEY J., MARY E. BARKWORTH*, and DOUGLAS 

R. DEWEY. Department of Biology UMC 45, Utah 

State University, Logan, UT 84322. - A Taxonomic 

Study of Leymus ambiguus and L. salinus 

Triticeae) 

(Poaceae: 

Morphological studies of populations in Utah, Idaho, 

Arizona, Wyoming, and Colorado belonging 

taxa of Leymus revealed that L. salinus 

to three 

is comprised 

of two subspecies, susp. salinus and subsp. salmonis 

comb. nov. Leymus ambiguus is distinct from these 

two taxa and occurs in the Front Range of Colorado 

and the Sangre de Christo mountains of New Mexico. 

Tetraploid (2n=28) and octoploid (2n=56) races occur 

in L. salinus subsp. salinus and L. ambiguus, but 

only tetraploids are known in L. salinus subsp. 

salmonis. A naturally occurring hexaploid (2n=42) 

was found in one population 

salinus. 

of L. salinus subsp. 

BAKER, MARC A.* and DONALD J. PINKAVA. 

Department of Botany and Microbiology, 


- Megasporogenesis and megagametogenesis 

in Opuntia fulgida, 0. spinosior and their 

triploid hybrids. 

Our preliminary analysis of sectioned ovules 

of Opuntia fulgida 0. spinosior, and their 

triploid hybrids has provided further evi- 

dence that 0. fulgida is an apomictic 

species, while 0. spinosior is largely 

sexual. Although both have 8-nucleate 

Polygonum type embryo sacs, only those of 

0. spinosior appear to be functional and 

derived via meiosis. This is the first 

report of normal megagametogenesis in 

Opuntia. Although we have not yet determined 

the exact nature of the abnormalities in 

diploid 0. fulgida, we have found the abnor- 

malities in triploid 0. fulgida and the 

triploid hybrids to exist.because of uneven 

segregation of chromosomes among the four 

gones. Micronuclei are often present. From 

materials examined, the position of the 

functional megaspore was random among the 

four nuclei of the tetrads, and abortion 

always occurred before the formation of a 

functional 8-nucleate embryo sac. 

BALLARD, JR., HARVEY E. Department of Biology, 

Western Michigan University, Kalamazoo, MI 49008. 

- Taxonomic revision of stemless blue violets 

(Viola) in the eastern United States. 

Difficulties in identification of stemless blue 

violets have traditionally been attributed to random 

morphological variation, intergradation, and rampant 

hybridization. Paradoxically, all studies to date 

have been based on species concepts first espoused by 

Brainerd and his contemporaries at the turn of the 

century. None have involved a re-appraisal of the 

original taxa to ascertain whether the problem lay 

with the violets themselves or with erroneous 

classifications superimposed on them. 

Specimens from 31 herbaria have been examined and 

numerous field observations of Michigan populations 

made to document morphological and ecological 

patterns in the stemless blue violets of the eastern 

United States. Five broadly defined but well-marked 

species, Viola cucullata, V. nephrophylla, V. 

pedatifida, V. sagittata, and V. sororia, have been 

recognized. Each species occupies a specific plant 

community (e.g., V. pedatifida in mesic prairie). 

Connecting the species are de novo hybrids and 

derivatives found in highly 

ecotones of adjoining plant 

disturbed sites and 

communities; forms in 

regions where communities intergrade; and forms that 

appear ancestral to the 5 ecologically isolated 

species. For convenience most intermediates have 

been placed in two polyphyletic species complexes 

called V. affinis and V. palmata. 

BANERJEE,UMESH C.*, JOHN RUFFIN, SUMANA G. 

BANERJEE,Department of Biology,North Carolina 

Central University,Durham,N.C.,27707. 

-Selection of high rubber yielding variety of 

Guayule (Parthenium argentatum Gray). 

During Cretaceous when angiosperms originated, 

most insect genera were already well established. 

These insect species were totally dependent on 

plants as a primary source of food supply.During 

the past several million years plants have util-

ized various strategies for their survival and 

to protect themselves from their predators.Among 

these, two strategies used by plants are very 

important.(1) Morphological Strategy:Plants have 

evolved various types of trichomes,spines,thorns, 

very tough epidermis,waxy coating on leaves,etc. 

for their defense mechanisms.(2) Chemical Protee- 

tio2: Various toxic chemicals and deterrents are 

produced by plants; examples of these are tannins, 

alkaloids,flavonoids,and milky juices(latex or 

rubber).Approximately 2,000 species of angiosp- 

erms are known to produce milky juice for their 

protection from predators,however,varieties with 

less latex are often eaten by the insects. Since 

the species of Guayule (Parthenium argentatum) 

also produce latex(rubber),we could easily select 

the high rubber yielding varieties by using nat- 

ural predators as a tool for the selection of 

plants from the natural population since those 

plants having high rubber content are less dam- 

aged by insects.This screening method have saved 

our time and labor,and we have selected plants 

which produce more rubber without going through 

conventional hybridization methods and without 

growing thousands of seedlings for selection pr- 

ocedure in the field condition.We have made our 

observations on natural populations growing wild 

in southwestern Texas. 

BARKLEY, T. M.*, R. L. MCGREGOR, and R. E. BROOKS. 

Herbarium, Division of Biology, Kansas State University, 

Manhattan, KS 66506 and State Biological 

Survey of Kansas, Lawrence, KS 66045. - Completion 

of the Flora of the Great Plains project. 

In 1973 the Great Plains Flora Association (GPFA) was 

formed among botanists of the region to prepare a 

floristic treatment for the grasslands of the central 

and northern U.S. The project has produced the Atlas 

of the Flora of the Great Plains and the soon-to-bepublished 

Flora of the Great Plains. The GPFA involved 

taxonomists in six states and twelve regional 

institutions, plus specialists from elsewhere, and 

it was supported by both national and local sources. 

The project operated through a "Memorandum of Cooperation" 

which is a quasi-legal agreement among GPFA 

participants. The organizational and procedural aspects 

of the project may be of interest to botanists 

who are contemplating broad floristic programs. 

BARKWORTH, MARY E. Department of Biology UMC 45, 

Utah State University, Logan, UT 84322. 

- Leymus Hochst. 

America. 

(Gramineae: Triticeae) in North 

Generic recognition 

by genomic, genetic, 

of Leymus Hochst. 

and morplhological 

is supported 

data. Much 

of the supposed overlap between it and other Nortlh 

American Triticeae reflects misunderstandinigs as to 

its limits. Members of Leymus are generally 

rhizomatous species with short, stiff, subulate 

glumnes; acute to shortly-awned lemmas; and large 

anthers. A few species are generally cespitose but 

produce short rhizomes in some populations. The two 

coastal species differ from the others in having 

flat, evidently veined, nerves. Intrageneric 

hybrids are relatively common but hybrids with other 

genera are very rare, particularly whea the 

frequency of sympatric populations is considered. 


BARKWORTH, MARY E. Department of Biology TIC 45, 

Utah State University, Logan, UT 84322. 

- Patterns of evolution in the Stipeae 

The Stipeae are well represented in Eurasia, North 

America, South America and Australia, 

number of species being in Eurasia. 

the largest 

The species 

generally occupy xeric to semi-xeric habitats but 

some species have become adapted to more mesic 

environments, including subalpine bogs. 

Similar suites of adaptative characteristics can 

be seen in all four areas. Species of the most 

xeric habitats have long awns with a strongly 

twisted colujmn; long, sharp calluses; large but 

narrow florets and lemmas with strongly overlapping 

margins. These features enable the caryopsis to be 

buried deeply in the soil during the wet season. In 

North America these characteristics can be seen in 

members of Stipa sect. Hesperostipa and 

Piptochaetium sect. Podopogon. Species of more 

mesic habitats differ in having shorter awns and 

florets; calluses that are often blunt; evenly, 

sometimes long, pubescent lemmas that are often 

and 

not 

strongly overlapping. Most North American species 

of Stipeae belong in this group. Long hairs on the 

lemma or awn are particularly common among species 

occupying 

habitats 

the drier habitats. Species of subalpine 

tend to have very narrow, erect leaves as 

well as the other characteristics listed for species 

of mesic environments. 

Each of these character suites appear to have 

developed independently in several different groups 

of Stipeae. This has resulted in considerable 

taxonomic 

elsewhere. 

confusion both in North America and 

BAYER, RANDALL J. Department of Botany, The Ohio 

State University, Columbus, OH 43210. - Ih.e 

compilospecies Antennarla neodlolca and Its 

possible- re-latlonship to diploid species cfJ the 

genus. 

The dioecious composite, Antennaria neodlolca sensu 

lato (Bayer and Stebbins 1982), is a taxonomically 

difficult, polyploid agamic complex found In the 

eastern United States and adjacent Canada. It has 

recently (Bayer and Stebbins 1982) been recognized to 

be composed of three subspecies hamely, AS neodiolca 

Greene ssp. canadensis (Greene) Bayer and Stebbins, 

ssp. neodiolc, and ssp. petaloldea (Fern.) Bayer and 

Stebbins. All populations of A, neodlolca are 

agamospermous and consist entirely of pistillate 

clones. It has long been thought that polyploid 

agamic complexes in Antennaria are the result of 

hybridization between and among diploid species. 

With this in mind, hybridizations were made among 

five diploid (2n = 28) species of Antennarla In an 

attempt to discover the origins of the A. neodlo[ca 

complex. Interspecific hybrids were obtained for 

most combinations of the five diploid species A. 

neglecta, A, plantaginifolla, A. racemosa, A 

sloItarla, and A vIrginica. Representative 

specimens of A neodlolca s.l., the five diploids, 

and all the interspecific hybrids were then subjected 

to a numerical analysis consisting of a principle 

components, cluster (UPGMA), and a discriminant 

analysis. Also included in the analysis were 

specimens of A. HoweiLLI Greene, which occurs In the 

northern Rocky Mountains. Results indicate that AS 

Howelill should be Included as a fourth subspecies of 

AS neodiolca s.l. and that the A neodlolca complex 

Is probably the result of complex hybridization 

Involving all diploid species of the genus except AS 

solItarla. Therefore AS neodlolca s.l. can be 

considered a typical compilospecies.


BELL, JOHN M.* and THOMAS R. SODERSTROM. 

Department of Botany, North Carolina State 

University, Raleigh, North Carolina 27650, and 

Department of Botany, Smithsonian Institution, 

Washington, D. C. 20560. - Anatomical approach 

to the placement of a new bamboo from Mexico. 

An undescribed scandent bamboo which is abundant in 

the Engelhardtia cloud forests of Oaxaca, Mexico, 

shows closest similarities to the genera Aulonemia 

and Olmeca. All three have a similar branch 

complement and a flower that contains three stamens 

and two stigmas. The open panicle of the new 

species resembles that of the former genus, but its 

narrow, elongate spikelets and prominent erect oral 

setae are like those of the latter. The fleshy 

fruits, which are characteristic of Olmeca, 

clearly differentiate it from Aulonemia, which has 

dry caryopses. Since fruiting material of the new 

species was not available for study, a detailed 

anatomical investigation was made of its leaves, 

and the results compared with those of the other 

genera. The leaf anatomy is typical of Olmeca in 

most respects but differs from Aulonemia in which 

all species exhibit the unusual presence of 

intercostal sclereids. While fruiting material 

will be necessary for precise classification, the 

evidence at hand suggests placement of the new 

bamboo in the genus Olmeca. 

BOHM, B.A.*, K.W. NICHOLLS and R. ORNDUFF. 

Department of Botany, University of British 

Columbia, Vancouver, B.C. V6T 1W5 and Department 

of Botany, University of California, Berkeley, CA 

94720. 

- Flavonoids and affinities of Menyanthaceae 

Dumortier. 

The Menyanthaceae is a family of aquatic or semiaquatic 

herbs comprising five genera: Menyanthes 

(1 sp.), Fauria (=Nephrophyllidium)(1 sp.), 

Nymphoides (ca. 20 spp.), Villarsia (ca. 14 spp.), 

and Liparophyllum (1 sp.). The family has most 

often been associated with the Gentianales, as the 

Menyanthaceae, or as the Menyanthoideae within the 

Gentianaceae, but its placement in the Solanales 

has been argued recently by Cronquist. We undertook 

a study of the flavonoid chemistry of the family 

with a view to examining relationships from a new 

perspective. A variety of kaempferol and quercetin 

glycosides occurred in all taxa studied (15 species 

representing all five genera). Several 0-methylated 

derivatives of these flavonols were more limited 

in their distribution but clearcut correlations 

with generic lines were not observed. The flavonoids 

clearly distinguish Menyanthaceae from the 

Gentianaceae, however. Major phenolic compounds of 

the Gentianaceae include C-glycoflavones and 

xanthones neither of which type has been reported 

from members of Menyanthaceae. 

BOLICK, MARGARET R. Division of Botany, 

University of Nebraska State Museum, 

Lincoln, NE 68588-0514. - A cladistic and 

A cladistic analysis of the extant genera of 

the Juglandaceae was done using c:haracters 

from thea f lovers, fruit, wood, and pollen. 

The Rhoipteleaceae was used as the outgroup. 

The resulting cladogram is congruent with 

Manning's (1978) c:lassification of the 

family. Platyc.ara, recognized by Manning 

as the subfamily Platycaryoideae, is the 

sister group to the remaining genera. 

Within the subfamily Juglandoideae each of 

the three tribes recognized by Manning is a 

monophyletic group: Juglandeae (Juqlans, 

Pteroc arya); Engelhardieae (Enj elhdia, 

A1laQroa, Oreomunnea); and Hicorieae (Car.a) . 

The modern distribution of the family shows 

three genera in southern Asia iPlatyca;a, 

PteQCA-r[a t En dia3; two genera in 

Central America (Alfaroa. Oremuunea) ; and 

two genera split between North America and 

Asia (iJns, Carya). Based on the 

cladogram, it is more parsimonious to assume 

that the Juglandaceae evolved in eastern 

Asia ithree dispersal events) than in 

eastern North America [five dispersal 

events). This conitradicts the extremely 

well known fossil pollen record of the 

family which suggests that the family 

originated in Nortth America-Europe. 

BOWMAN, ROBERT N. Dept. of Botany and Plant Path., 

Colorado State University, Fort Collins, CO 80523. 

- Intraspecific variability of leaf cuticle alkanes 

in Sedum lanceolatum (Crassulaceae) along an elevational 

gradient. 

The utilization of leaf waxes in elucidation of biosystematic 

relationships is well documented. This 

study investigated the influence of field conditions 

on alkane production in a taxonomically unambiguous 

species, S. lanceolatum Torr. Alkanes from individuals 

representing 44 populations ranging in elevation 

from 1598-3568 m were analyzed using gas chromatography. 

Relative percentages of 15 alkanes were determined 

for each population. Characterization of 

variability patterns in field-collected samples indicates 

no significant correlation 

and elevation. Cluster analysis 

between any alkane 

by cases based on 

total alkane variability shows no correlation with 

elevation even though localized biotypes may be in 

evidence. Near normal distribution of amalgamated 

distances derived from alkane proportions suggests 

that inherent variability is better explained by 

genetic constitution than by phenotypic plasticity. 

Results suggest that environmental factors associated 

with an elevational gradient are not directly responsible 

for alterations in expressed alkane phenotypes. 

Thus, at least in S. lanceolatum, fieldcollected 

alkane samples are meaningful in systematic 

interpretations. 

BRECKON, GARY* and VIVIAN NEGRON ORTIZ. 

Depto. de Biologia, Universidad de Puerto 

Rico, Mayaguez, PR 00708. - Pollination of 

Zamia pMiLla by fungus-gnats. 

Circumstantial evidence from Cambalache 

forest, Puerto Rico indicates that nocturnal 

visitation by a fungus-gnat (Diptera, 

Mycetophilidae) effects pollination in 

Zamila punila Lo subsp. pumila. Tne fungus 

gnat is the only consistant visitor to both 

male and female cones; visitation occurs 

between 10 p.m. and 2 a.m.; both cones 

produce an odor similar to that of fresh 

mushrooms; the odor is detectable bet;ween 

8 p.m. and 2 a.m.; feeding larvae of thne 

fungus-gnat are present in post-pollination

male cones, they only rarely are found in 

the female cone. Larvae reared in harvested 

microstrobilii develop into adults. Reasons 

for visiting the megastrobilii are not 

evident: the female cone may be a mimic of 

the male cone, but is unacceptable for 

oviposition and/or subsequent development; 

or the pollination drop may provide a reward 

for the visiting adult. 

BRETTING, P. K. Natural History Division, 

Institute of Jamaica, 12 East Street, Kingston, 

Jamaica. - Breedinq systems in Proboscidea 

(Martyniaceae). 

Floral characteristics, degree of self-compati- 

bility, P/S (pollen-seed ratios--equivalent to 

pollen-ovule ratios), and observation of insect 

visitors were used to estimate breeding systems in 

nine taxa of Proboscidea (Martyniaceae). Bees 

visit the flowers of most species, and are 

apparently the most important pollinators. 

Proboscidea sabulosa is primarily autogamous, P. 

altheaefolia primarily xenogamous, and P. 

louisianica facultatively xenogamous. Within P 

triloba, subsp. triloba is facultatively xenogamous, 

but subsp. diversifolia is relatively more auto- 

gamous. Within P. parviflora, subsp. oarviflora 

is primarily autogamous, subsp. cracillima probably 

facultatively xenogamous, and subsp. sinaloensis 

primarily to facultatively xenogamous. The evolut- 

ion of relatively more autogamous subspecies in P. 

oarviflora and P. triloba has involvad very similar 

changes in floral characteristics and degree of 

self-compatibility. Separate numerical 'xenogamy- 

autogamy' indices constructed from self-compatibi- 

lity data and from floral characteristics are signi- 

ficantly correlated with each other and with pollen 

number, but are uncorrelated with P/S ratios and 

seed number. Seed (and ovule) number may be deter- 

mined by factors related to successful dispersal 

rather than reproductive efficiency. Floral 

characteristics and degree of self-compatibility 

hence may be more precise measures of breeding 

systems in Proboscidea than are P/S ratios. 

BRINK, DON* and J. M. J. DE WET. Crop Evolution 

Laboratory, Department of Agronomy, University of 

Illinois, 1102 South Goodwin Avenue, Urbana, IL 

61801-4798. - Sections in Tripsacum (Gramineae). 

There are two main infrageneric groups within 

Tripsacum and they differ in several correlated 

characters. Variation is essentially continuous 

between the groups for any single character but two 

well defined modes of variation emerge when 

combinations of characters are considered. There 

are few intermediates and the vast majority of 

specimens studied fall unambiguously into one group 

or the other. These two groups are recognized as 

sections. They are the most distinct and well 

defined natural groups within the genus. Section 

Fasciculata differs from section Tripsacum in having 

one spikelet of a staminate pair at a rachis node 

with a long, thin pedicel rather than both spikelets 

subsessile or one supported by a short, thick 

pedicel; thinner internodes in the male section of 

each inflorescence branch; and a longer primary axis 

of the terminal inflorescence with more internodes 

and more branches. Section Tripsacum has a wide 

geographical1 range extending from the central and 

northeas tern United States to central1 South America. 


Section Fasciculata has a more restricted 

distribution extending from southern Arizona to El 

Salvador. 

BROWN, BRETT P.* & JAMES E. ECKENWALDER. Department 

of Botany, University of Toronto, Toronto, 

Ontario, Canada M5S lAl - The origin of the cardinal 

climber, Ipomoea X multifida (Raf.) Shinn. 

The cardinal climber is a popular ornamental morning 

glory with red flowers and lacerate leaves. Unlike 

its diploid congeners in sect. Quamoclit, Ipomoea x 

multifida is an allotetraploid. The origin of this 

hybrid should be unproblematic since its originator 

at the turn of the century, L. Sloter, states that he 

crossed I. coccinea with I. quamoclit, producing 

sterile hybrids for 11 years until a single seed was 

produced that has given rise to all cultivated cardinal 

climbers. However, at the time Sloter worked, 

8 other species now recognized as distinct were all 

called I. coccinea, and 4 of these were also cultivated 

with I. coccinea. We undertook a crossing program 

among these 5 candidates for parenthood and the 

unproblematic parent, I. 

brids, and I. x multifida 

quamoclit. Parents, F1 hywere 

grown in a randomized 

block design and scored for various vegetative and 

floral characteristics. This data was analyzed using 

Principal Components Analysis and Canonical Variates 

Analysis. The results of the crossing program and of 

the morphometric analyses supported the parentage of 

I. coccinea, even though the F hybrid I. coccinea x 

I. quamoclit was morphologically distinct from the 

cardinal climber. This parentage was confirmed when 

6 seeds were produced on the F1 plants at the rate of 

about 1 per 40,000 ovules. These seeds have produced 

tetraploid plants that are morphologically identical 

to the cardinal climber *and freely intercrossable 

with it but not with either diploid parent species or 

with their own F1 hybrid parents. The cytological 

mechanism leading to tetraploid formation appears to 

be the union of unreduced gametes that are produced 

in higher frequencies in the F1 hybrid than in the 

diploid parent species. 

BRUEDERLE, 

LEO P.* and DAVID E. FAIRBROTHERS. 

Biological Sciences (Botany), Rutgers University, 

Piscataway, N.J. 08854. - Variability and tax- 

onomic usefulness of achene and perigynium charac- 

ters of the Carex crinita complex (Cyperaceae). 

The Carex crinita complex comprises seven taxa 

variously organized into two or three species and 

corresponding varieties. These have been distin- 

guished on the basis of infructescence structure; 

achene contortion; perigynium shape, dimensions, 

and ultrastructure; sheath pubescence; culm height; 

and leaf width. The majority of these characters 

exhibit continuous variability throughout the com- 

plex, while others are disjunct and not necessarily 

correlated with a particular taxon as previously 

described. A comparative study was undertaken 

examining perigynium, and achene morphology and 

ultrastructure utilizing SEM and light microscopy. 

Features examined were achene epidermis, achene 

contortion, pergynium ornamentation, and perigynium 

dimensions. Characters classically used to distin- 

guish among taxa were found to be less useful for 

classification purposes than less frequently used 

features, in particular perigynium ornamentation 

and dimensions. SEM examination of achenes revealed 

less useful variability than that detected among 

other taxa within the genus, e.g. Montanae, Lupulinae.


BRUNER, JOE. Department of Botany, The Ohio State 

University, Columbus, Ohio 43210. - Systematics of 

the Schizachyrium scoparium group (Poaceae) in 


The Schizachyrium scoparium group ranges from North 

to South America. Species of this group are morphologically 

distinct from other members of the genus. 

The North American representatives of this group, 

some ten tetraploid (2n=40) species, have not been 

the focus of a systematic study of any depth until 

the present time. Greenhouse comparisons of growth 

and habit, consideration of habitat and distributions, 

and phenetic studies have clarified the species variation 

and tend to support the taxonomic integrity of 

most of the species. The analysis of the following 

species pairs, however, suggests that the latter 

taxon is not sufficiently distinct from the former to 

warrant specific status: scoparium/littorale, 

cubense/rhizomatum, and gracile/sericatum. The cleistogamous 

reproductive mode of S. gracile and S. sericatum 

is an anomaly in this primarily outcrossing 

group, raising the question about how closely related 

they are to the other species. S. niveum, a severely 

restricted endemic of central Florida, is quite 

distinct from the other North American species and in 

a phenetic analysis groups more closely with Central 

American and South American species. 

CAMPBELL, CHRISTOPHER S. Department of Botany and 

Plant Pathology, University of Maine, Orono, Maine 

04469. - Systematic relationships of the grass 

genus Brachyelytrum. 

Where Brachyelytrum belongs in the Gramineae is 

enigmatic. It has traditionally been associated with 

the Stipeae or Pooideae on the basis of morphological 

similarity. Anatomical data from embryos and leaves 

contradict these morphological similarities as do new 

data on the seedling morphology of Brachyelytrum. In 

the width and orientation of the first seedling leaf 

blade, Brachyelytrum resembles stipoids and pooids, 

but it differs from most of them in its short first 

internode (the seedling mesocotyl) and lack of 

adventitious roots at the coleoptilar and scutellar 

nodes. Actually, Brachyelytrum is closer to various 

members of the Bambusoideae (sensu lato -- including 

woody bamboos, herbaceous bambusoids and oryzoids) in 

embryo anatomy, some leaf epidermal features and the 

first internodes and lack of adventitious roots of 

the seedlings. On the whole, however, the genus 

appears to be distantly related to other grasses. 

The current distribution of its two taxa -- one 

species or variety in the Eastern United States and 

the other in China and Japan -- suggests considerable 

geologic age and the possibility that it represents 

an early departure from the probable birthplace of 

grasses in tropical forests. 

CANNE, JUDITH M. Department of Botany and Genetics, 

University of Guelph, Guelph, ON. NlG 2W1. -Section- 

al limits in North American Agalinis Raf. 

(Scrophulariaceae). 

Recent work with the North American species of 

Agalinis indicates that the infrageneric taxonomic 

interpretations accepted by F.W. Pennell in his 

treatment of the genus in the 1920 's and 1930 's 

require modification. The following features form 

the primary bases for the present circumscription of 

sections and subsections: corolla form; patterns of 

pube scence on the corollas; morphology of the calyx; 

capsule shape; color, size and surface patterns of 

seeds; morphology and anatomy of leaves and stems; 

morphology of seedlings; organization of the inflor- 

escence; chromosome number. Two of the larger groups, 

section Erectae with a base chromosome number of x= 

13 and section Purpureae subsection Purpureae with a 

base chromosome number of x=14, are maintained 

essentially as accepted by Pennell except that two 

species from other subsections of section Purpureae 

are moved to section Erectae. Subsection Setaceae 

(x=14) of section Purpureae is reduced to four 

species. The small sections Aspereae and Hetero- 

phyllae are united. Some members of section Tenui- 

foliae are combined with the species of section 

Purpureae subsection Pendunculares to form a 

separate section. The monotypic section Linifoliae 

is maintained. The small genus Tomanthera Raf. is 

reunited with Agalinis. 

CANTINO, PHILIP D. Department of Botany, 

Ohio University, Athens, OH 45701. 

- Chromosome numbers, chromosome size, 

and intergeneric relationships in 

subtribe Melittidinae (Labiatae). 

The Melittidinae (Labiatae) was established 

as a subtribe by Endlicher, perpetuated by 

Bentham and Briquet, and has generally been 

recognized by more recent authors. 

Endlicher, Bentham, and Briquet all delim- 

ited the group on the basis of gross 

morphology of the calyx and corolla. Few 

of the character states they cited are 

found in all genera of the Melittidinae, 

and none are unique to the subtribe; they 

occur in various combinations elsewhere 

in the family. Chromosome numbers have 

been reported for two of the six genera of 

the Melittidinae (Melittis, 2n=30+ 2-8B; 

Physostegia, 2n=38,76). New counts, 

reported here, establish a diploid number 

of 18 for Synandra and Macbridea and 28 for 

Brazoria. Chromosomes of Synandra and 

Macbridea are three times as large as those 

of Brazoria and Physostegia. Neither 

cytological data nor traditional floral 

characters support the retention of the 

Melittidinae as a natural grouping. 

CHINNERY, LOUIS E. Department of Biology, 

University of the West Indies, P.O. Box 

64, Bridgetown, Barbados. - Vation of 

raI -floret 1eut h in Bidens iilosa L., 

impiications for taxonlomj in the 

As tereae2. 

Largely on the basis of capitulum 

morphology, Sherff (1937) split Bidens 

npi.Iosa into a number of varieties and forms. 

The ray-florets from plants of varieties 

radiata and mjnor, which he separated on the 

basis of ray-floret length, have been 

measured. The results show (a) that 

variation of ray-floret length is continuous 

within varieties and that the two varieties 

merge, (b) that there is a linear 

relationship between ray-floret length and 

the nuimber of disc~-f1orets which have 

opened, and (c) that this is due to an 

increase in le;ngth of both the ligule and

tube portions of the corolla. The results 

are compared with data on the variation of 

ray-floret length in Senecio vulcaris L.. 

The use of ray-floret size in identification 

and classification of ligulate members of 

the Asteraceae is questioned. 

CHOLEWA, ANITA F. Department of Biological 

Sciences, University of Idaho, Moscow, ID 83843 

- A biosystematic study of Rocky Mountain populations 

of Sisyrinchium section Bermudianae. 

Since the early 1900's, when Bicknell and Greene 

described many of the North American species of Sisyrinchium 

(Iridaceae), only the Pacific Northwestern 

members of the genus have received a biosystematic 

treatment. As a result, much confusion still exists 

regarding the taxonomy of other populations. A biosystematic 

study of the Rocky Mountain populations 

was made to discover and define discontinuities with 

taxonomic value. Detailed morphological examinations 

were supplemented with chromosome counts, flavonoid 

chromatographic patterns, breeding system studies, 

and artificial hybridizations. Based on data gathered 

from these areas, five groups were defined. Three 

of these correspond to S. idahoense (including S. 

heterocarpum and S. juncellum), S. montanum (including 

S. alpestre and S. heterocarpum), and S. septentrionale. 

A fourth group, _. radicatum, is tentatively 

being separated from the closely related S. 

demissum. The fifth represents a new species: 

S. pallidum Cholewa sp. nov. ined., which is characterized, 

in part, by pale blue flowers. 

CHUANG, T. I.* and L. R. HECKARD. Department of 

Biological Sciences, Illinois State University 

Normal, IL 61761 and Jepson Herbarium, Department 

of Botany, University of California, Berkeley, CA 

94720. - Systematic significance of seed-surface 

features in Orthocarpus (Scrophulariaceae). 

Scanning electron microscope and light microscope 

examination of seed-coat features of 26 species of 

Orthocarpus have allowed recognition of many species- 

level differences (summarized in a key) and of three 

seed-coat types that parallel taxonomic subgroups 

but support realignments at generic and infrageneric 

levels. Type 1 seeds (subg. Orthocarpus, sect. 

Orthocarpus) have a lateral hilum, sculptured inner 

tangential seed-coat walls, and a tightly fitting 

outer seed coat. They are very similar to seeds of 

Cordylanthus. Seeds of Types 2 and 3 have a 

terminal hilum and membranous inner tangential cell 

walls. Type 2 seeds (subg. Orthocarpus, sects. 

Castillejoides and Cordylanthoides, with one excep- 

tion) have a net-like, loosely fitting outer seed 

coat that shows close relationship to seeds of 

Castilleja. Inner tangential walls of Type 2 seeds 

normally rupture. Type 3 seeds (subg. Triphysariaa, 

with two exceptions) have a tightly fitting outer 

seed coat and inner tangential walls are always 

retained. Seed features support evidence from 

floral morphology and chromosome numbers that 

Orthocarpus as currently recognized is not a mono- 

phyletic lineage. 

CLARK, CURTIS. Biological Sciences, 

California State Polytechnic University, 

Pomona CA 91768. - Systematics and 

biogeography of the Encelia frutescens 

all ianc e IAsterac e ae: He1 iant1 h aen I) 

Encelia frutescens and three other taxa 

comprise a monophyletic group diagno sed by 


a scant strigose leaf pubescence of short, 

broad multicellular hairs, and reduced or 

missing rays. The taxonomy of the group has 

been confused by inadequate collection, 

interspecific hybridization, and misinter- 

pretation of the importance of raylessness. 

Recent treatments lump all four taxa plus 

one distantly related species and two hy- 

brids in a single polymorphic species. 

Cladistic analysis provides an hypothesis 

of relationships among the taxa. Encelia 

"resinosa", the sister taxon of the other 

three, has the most northern distribution, 

in the deserts of the Colorado Plateau. E. 

"Grand Canyon", sister taxon to the remain- 

ing two, occurs only in its namesake. The 

two remaining taxa, E. frutescens and E. 

"San Felipe", may represent a single evol- 

utionary species; the former is widespread 

in the northern Sonoran and Mojave deserts 

and the latter inhabits northeastern Baja 

California. From vegetation records pre- 

served in ancient woodrat nests, it is evi- 

dent that as recently as 8000-yr b.p. the 

region was too cold to support the species 

in their present form. The older species 

have moved north into areas of new desert, 

and newly derived species now occupy the 

harsher deserts to the south. 

CLARK, LYNN G. Department of Botany, Iowa State 

University, Ames, IA 50011. 

- Bud morphology in Chusquea (Poaceae: 

Bambusoideae). 

Chusquea, the largest genus of bamboos, with over 

100 species, is distinguished by its solid culms, 

multiple independent buds per node and chromosome 

number of 2n=40. The bud complement in Chusquea, 

consisting of one primary bud subtended by 2- 

numerous smaller independent subsidiary buds, 

apparently is uni-que among bamboos. The bud 

morphology of approximately 50 species of Chusquea 

was investigated using dried bulky specimens or 

material fixed in FAA. Two types of primary buds 

were found within Chusquea. One, the "triangular" 

type, is much more common and like those of other 

bamboos. The other, the "circular" type, to date 

has been found in only nine species of Chusquea. 

The arrangement of the subsidiary buds is highly 

variable, and appears to be species-specific. Among 

the species studied, 10 basic patterns of bud 

arrangement are recognized, with individual 

variation in the prophyllum, size of buds and other 

characters occurring according to species. These 

bud patterns appear to be important in determining 

evolutionary trends within the genus. 

CLEMANTS, 

STEVEN E. Herbarium, New York Botanical 

Garden, Bronx NY 10458. - Flavonoids of Befaria. 

The genus Befaria (Ericaceae: Rhododendroideae), the 

only member of the tribe Befarieae, was surveyed for 

leaf flavonoids. Quercetin glycosides are found 

throughout the genus. Of more limited distribution 

and thus more interesting taxonomically, are 

myricetin glycosides, 3,5-0-dimethylquercetin 

(Caryotin) and 5-0-methylflavonol glycosides. 

Flavonol aglycones are also present in some species. 

The Befarieae is often placed near the Cladothamneae 

because they are both polypetalous, however the 

Cladothamneae lack 5-0-methyflavonols and Caryotin. 

The Rhodoreae, also considered closely related to 

the Befarieae, have 5-0-methyflavonols and Carotin


(Rhododendron). This evidence supports the idea 

that the Befarieae is more closely related to the 

Rhodoreae than to the Cladothamneae. The flavonoid 

data will be presented in a phylogentic context 

using cladistic methods. 

CLEMANTS, STEVEN E. Herbarium, New York Botanical 

Garden, Bronx NY 10458. 

Mutis ex L. 

- Systematics of Befaria 

Befaria (Ericaceae: Rhododendroideae) is a shrubby 

or arborescent genus found in pine woods in Florida 

and Cuba, and in montane forests, subparamo and 

paraom areas of Mexico, Central America and South 

America. The genus is placed within its own tribe 

and is related to the Rhodoreae and the Cladothamneae. 

Past investigations of the genus have 

resulted in two different subgeneric classifications. 

Fedtschenko and Basilevskaja relied upon inflorescence 

morphology and pubescence to define four sections 

and two subsections, many of which are unnatural 

assemblages. Mansfeld and Sleumer relied on anatomy 

and inflorescence morphology to devide the genus 

into two sections, the racemosae (with one species) 

and the glaucae (with 25 species), and no further 

subdivisions were made. In the present study floral 

morphology, especially the relative spreading of the 

petals, is used to make a more natural subgeneric 

classification. At the species level, over reliance 

on hair types by previous workers resulted in unnecessary 

splitting. Field and herbarium studies 

suggest that hair type is often variable within populations 

and should not be relied upon a priori as a 

specific character. A preliminary phylogeny of the 

genus will also be presented based upon morphology, 

anatomy and chemistry. 

CONNOLLY, VICTORIA* & JAMES E. ECKENWALDER. 

Department of Botany, University of Toronto, 

to, Ontar'io, Canada M5S lAl - Hybridization 

Toronbetween 

white 

Ontario. 

poplar and native aspens in southern 

Populus alba is an introduced 'poplar species that 

often hybridizes with the two native aspen species in 

the northeastern United States and adjacent Canada. 

Hybrids among the three species differ greatly in relative 

abundance in Ontario. P. x rouleauiana (P. 

alba x P. grandidentata) is far more prevalent than 

either P. x heimburgeri (P. alba x P. tremuloides) or 

P. x smithii (P. grandidentata x P. tremuloides). We 

sought to determine at what stage(s) of the hybridization 

process this advantage of P. x rouleauiana 

might occur. Prepollination barriers interposed by 

differences in flowering phenology are not adequate 

to explain the discrepancies. Differences in viability 

of seeds of hybrid origin, when present, are 

inconsistent with differences in prevalence of the 

hybrids. A complete crossing program among several 

male and female genotypes of each species was undertaken 

to assess variations in compatability among 

them. Catkins were collected at intervals in a time 

sequence after pollination for each pistillate parent 

in the crossing program. Observations of pollen germination 

and pollen tube growth were made on three 

stigmas from each catkin using fluorescence microscopy. 

The percentage of pollen germinated, rate of 

growth of pollen tubes, and rate of penetration of 

the ovary all differed among different crosses. 

There was considerable variation among different 

genotypes within species and reciprocal crosses did 

not behave similarly. There were striking differen- 

ces in the behavior of pollen tubes on the stigmas. 

These variations cloud the interpretation of the 

results, but it seems that here, too, there is no 

obvious basis for the predominance of P.x rouleauiana 

CRINS, WILLIAM J.* and PETER W. BALL. Department 

of Biology, Erindale Campus, University of 

Toronto, Mississauga, Ontario L5L 1C6. - Revisionary 

studies 

results. 

in Carex section Extensae: preliminary 

The eight North American members of Carex section 

Extensae fall into three groups based on morphology. 

The first two groups are characterized by divergent 

or reflexed perigynia within the pistillate spikes. 

Carex cryptolepis, C. flava, and C. lepidocarpa possess 

perigynia in which a distinct angle is formed 

between the body and the beak. Carex demissa, C. 

saxilittoralis, and C. viridula lack this feature 

The remaining taxa, C. extensa and C. hostiana, form 

a third group in which the perigynia ascend within 

the pistillate spikes. The majority of the species 

in the section occur in both North America and 

Europe. However, no attempt has previously been 

made to compare the North American and European 

plants. In the present study, morphological variation 

and discontinuities within the complex have 

been investigated through the use of principal components 

analysis and discriminant analysis. The 

initial phase of the investigation was conducted 

using 53 morphological characters. On the basis of 

these analyses, it appears that C. saxilittoralis is 

not distinct, and should probably be united with C. 

viridula. Morphological and cytological evidence 

suggest that the European C. serotina is conspecific 

with C. viridula. The European C. scandinavica is 

also allied with C. viridula, but may represent a 

distinct taxon at a rank below that of species. The 

North American plants of C. hostiana, considered to 

be varietally distinct by Fernald, do not differ 

significantly from the European plants.' The remainder 

of the North American species are distinct from 

each other morphologically and cytologically. 

! 

Clx3., OA .10,Asz B. iep)artinent of Botany, 

.4.oulri 

Stt Louis, 

5ot llicaI Gir(lel, P-0. 0. 

f.O (E3110 - A 1iSCuSsioi 

Box 299, 

Of the 

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CROW, GARRE'IT E. Department of Botany and Plant 

Pathology, University of New Hampshire, Durham 

NH 03824.- New England's rare, threatened, and 

endangered vascular plants. 

New England's flora, although recent in development 

(post-glacial), is rich and diverse. The native 

vascular plant flora is estimated to number 2570 taxa 

and of those indigenous to our region, 479 taxa 

(18.6% of the flora) are viewed as rare, threatened, 

or endangered. Pedicularis furbishiae, Potentilla 

robbinsiana, and Isotria medeoloides have been 

officially listed as "Endangered" under the 

Endangered Species Act of 1973, and 24 are currently 

under consideration by the U. S. Fish and Wildlife 

Service for listing. Additionally, 74 taxa are of 

"national significance," including many taxa whose 

occurrence within the United States is extremely 

limited, but may, for instance, be more frequent in 

arctic regions of North America. Several critical 

species are discussed, including distribution, 

phytogeographical affinities, threats, and measures 

for protection arid recovery. 

DAVIS, JERROLD I. Department of Botany KB-15, 


- Genetic 

of Washington, Seattle, WA 98195. 

assimilation of phenotypic plasticity 

in Puccinellia (Poaceae). 

Experimental study of phenotypic plasticity in 

Puccinellia suggests that genetic assimilation of 

differences in phenotypically plastic characters has 

been an important process in evolutionary 

diversification in this group. Divided clones 

representing several taxa were cultured in a series 

of salt- and drought-stress treatments representing 

naturally encountered environmental conditions. For 

each of 41 characters, genetic variation (among 

clones) and environmentally induced variation (among 

treatments; phenotypic plasticity) were calculated 

by analysis of variance. These two sources of 

variation are positively correlated; genetic 

variation is greatest in the most plastic characters 

(e.g., width of leaf blade, length of inflorescence). 

While plastic characters exhibit high levels of 

genetic variation among taxa, they are taxonomically 

weak because plasticity obscures the genetic 

differences. The most reliable taxonomic characters 

are non-plastic ones with moderate rather than high 

levels of interspecific variation. It is possible 

that differences among taxa in some of these 

characters result from chance fixation events, 

rather than from natural selection. 

DAVIS, JERROLD I. Department of Botany, KB-15, 


- Revision 

of Washington, Seattle, WA 98195. 

of the Puccinellia nuttalliana complex 

(Poaceae). 

A systematic revision of the Puccinellia nuttalliana 

complex is presented. Plants of this group are 

endemic to saline and alkaline habitats, and exhibit 

a strong plastic response to the drought- and saltstress 

conditions under which they grow. Character 

plasticity obscures genetically determined 

relationships, thereby contributing to taxonomic 

difficulties in the group. Multivariate analysis 

based on characters determined experimentally to be 

relatively non-plastic clarifies the delineation of 

taxa. Important characters include number and angle 

of divergence of inflorescence branches, indument of 

pedicels, shape of glume apices, and length and 

margin of lemmas. Patterns of anatomical variation 

of foliar surfaces support the evolutionary 

rel ati onshi ps deduced from morphol ogi cal characters . 


Further support for these relationships is derived 

from chromosome numbers, breeding systems, and 

habitat preferences of the taxa. 

DONOGHUE, MICHAEL. Department of Botany, San 

Diego State University, San Diego, CA 92182-0058. 

- Pollen diversity in the Caprifoliaceae sensu 

lato and the evolution of the exine in Viburnum. 

Studies with the scanning electron microscope reveal 

two very different kinds of pollen in the Caprifoliaceae 

s.l. The ten genera of the Caprifoliaceae 

sensu stricto have large, oblate to spheroidal, 

usually tectate grains, while Viburnum, Sambucus, 

and Adoxa have smaller, usually prolate grains, with 

an incomplete tectum. This distribution of pollen 

types is congruent with many othei characters. There 

is reason to think that Viburnum, Sambucus, and 

Adoxa form a monophyletic group, and hence it is appropriate 

to consider the evolution of pollen within 

this clade. Since the exine in Sambucus and Adoxa 

is reticulate with psilate muri, this kind of pollen 

(Type A) is considered ancestral within Viburnum. 

Pollen with a reticulate exine but with scabrate muri 

(Type B) is considered to be derived from the ancestral 

condition. In turn, retipilate or pilate pollen 

with scabrate pilae (Type C) is thought to be derived 

from Type B pollen. On cladograms of Viburnum that 

most parsimoniously account for a wide variety of 

characters a single change is required from Type A 

to Type B pollen, and there are changes from Type B 

to Type C pollen in sections Lantana, Lentago and 

Pseudotinus. Small but consistent differences between 

Type C pollen in these three sections lend 

support to the hypothesis that this kind of pollen 

has arisen by convergence and cannot be considered 

a synapomorphy. This study provides an example of 

the relationship between cladistic analysis and the 

analysis of particular character transformations. 

DORN, PAMELA 

S.* and WILLIAM L. BLOOM. Dept. of 

Botany, University of Kansas, Lawrence, KS 66045. 

- Anthocyanin variation in an introgressive 

complex in Clarkia. 

Clarkia nitens and C. speciosa ssp. polyantha are 

distinct species which differ chromosomally, morph- 

ologically, and physiologically. The most conspic- 

uous difference is flower color; C. nitens has yellow 

stigmas and petal parts while those of C. s. ssp. 

polyantha are lavender or purple. Geographically 

intermediate between C. nitens and C. s. ssp. poly- 

antha is a third taxon, C. s. ssp. polyantha-North, 

which is chromosomally very similar to C. nitens, 

but morphologically similar to C. s. ssp. polyantha. 

Previous studies indicate that C. s. ssp. polyantha- 

North arose by the introgression of C. s. ssp. poly- 

antha genes into C. nitens. The only significant 

morphological difference between C. s. ssp. polyantha 

and the hybrid derivative is that C. s. ssp. poly- 

antha-North flowers are darker purple. Available 

evidence suggests that this occurred as a result of 

character displacement. In addition to its increased 

intensity, the purple of C. so ssp. polyantha-North 

is genetically more dominant to the yellow of C. ni- 

tens than is the purple of C. s. ssp. polyantha. 

Analysis of anthocyanins shows that the 3-glucosides 

and 3,5-diglucosides of malvidin, cyanidin, and 

delphinidin are present in each taxon, although var- 

iation is observed in both total anthocyanin content 

and relative proportions of individual compounds.


The increased purple intensity of C. s. ssp. poly- 

antha-North is due to greater concentrations of 

cyanidin and delphinidin glucosides than are present 

in C. s. ssp. polyantha. Continuing hybridization 

and biochemical studies should elucidate the genetic 

control of the increased purple intensity of C. s. 

ssp, polyantha-North and its increased genetic 

dominance. 

DOYLE, JEFF J.* ROGER N. BEACHY and WALTER H. 

LEWIS. Department of Biology, Washington University, 

St. Louis, MO 63130. - Ribosomal genes of 

Claytonia (Portulacaceae)--molecular cloning. 

The ribosomal gene (rDNA) tandem repeating units of 

various cytotypes from the two eastern North American 

species of Claytonia were initially compared by restriction 

endonuclease mapping using isolated total 

nuclear DNA. The variation observed in this type of 

experiment appears due to gain or loss of recognition 

sequences (usually six base pairs in length) required 

for cleavage by the restriction endonucleases, and is 

for the most part localized in the nontranscribed 

spacer separating the 18S and 25S ribosomal genes. 

In order to study this variable region in more detail, 

molecular cloning of Claytonia rDNA was undertaken. 

Genomic libraries were prepared using the cloning 

vector pHC 79, which is capable of incorporating over 

30 kilobases of foreign DNA. Libraries were screened 

using the rDNA repeat from soybean, and those colonies 

containing Claytonia rDNA sequences were isolated and 

subcloned for more efficient handling into the bacterial 

plasmid pUC 12. Restriction mapping of rDNA 

clones indicates that some restriction endonuclease 

sites in the genomic DNA, though present, are not 

accessible to enzymes (perhaps due to some modification), 

and suggests caution in analysis of genomic 

digestion patterns. Hybridization probes prepared 

from Claytonia rDNA clones appear to be of great 

utility in elucidating patterns of variation within 

the eastern North American Claytonia complex. 

DOYLE, JEFF J.* BETH F. LADIN and ROGER N. 

BEACHY. Department of Biology, Washington Univer- 

sity, St. Louis, MO 63130. - Seed storage protein 

variation and evolution in Leguminosae tribe 

Phaseoleae. 

Glycosylated seed storage proteins with similar phys- 

ical and chemical properties occur throughout the 

Leguminosae. Because these proteins appear to evolve 

at a rapid rate they may be useful indicators of evol- 

utionary relatedness at various taxonomic levels. We 

hawe screened seed protein extracts of over 60 legume 

genera for reactivity to antisera prepared against 

the glycosylated seed storage protein of Glycine max. 

Screening involved SDS-polyacrylamide gel electro- 

phoresis of immunoprecipitated proteins, which allows 

the determination of the molecular weights of homo- 

logous subunits, as well as the more sensitive enzyme- 

linked immunosorbent assay (ELISA). Sampling empha- 

sized the tribe Phaseoleae, from which all eight sub- 

tribes were examined. Greatest homology occurs, as 

expected, within the subtribe Glycinineae, where 

similar subunit patterns occur in many genera. A 

characteristic feature of this subtribe is the occur- 

rence of high molecular weight (above 70,000 daltons) 

polypeptides. Other subtribes of the Phaseoleae show 

varying degrees of relatedness to the test antisera; 

of note is the strong homology shown by the taxonom- 

ically difficult Erythrina. Weaker homology is found 

beyond the Phaseoleae in the Tephrosieae, Desmodieae, 

Robinieae and Sesbanieae. The imperfect correlation 

between taxonomic position and antigenic homology is 

likely due to the lability of the genes encoding the 

proteins; a comparison of these genes suggests that 

duplications of gene regions, coupled with divergent 

selection pressures on different domains of the pro- 

teins and their genes could produce the observed net- 

work of protein relationships. 

DUGLE, JANET R., Environmental Research, 

Whiteshell Nuclear Research Establishment, 

Pinawa, MB, ROE 1LO. 

-What is "key" about key characters? 

Taxonomic characteristics and classification systems 

have been described as natural or artificial, and it 

is generally believed that key characters should be 

as natural as possible. Many factors influence the 

development and usefulness of key characters for 

identification and classification of plant material. 

One of these, the environmental plasticity of a 

character, (the phenotypic change occurring as a 

result of a change in environment) is very important. 

Some new insights into the effect of the environment 

on plants can be gained by a study of plants which 

have grown under long-term low dose rates of gamma 

radiation in the Field Irradiator - Gamma area of 

mixed boreal forest in eastern Manitoba. Among the 

key characters that are influenced by environmental 

factors (in this case, gamma radiation) are leaf 

margin, number of leaflets, phyllotaxy, branching, 

length to width ratios, color of petals, number of 

flowers, size of fruits, and phenology of the 

plant. Some species exhibit more plasticity of 

morphological expression than do others. A few 

examples of species exhibiting varying characters 

are Lonicera dioica, Fragaria virginiana, Populus 

tremuloides, Fraxinus nigra, BetuZa papyrifera, 

UZmus americana, AraZia nudicaulis, GaZium 

septentrionaZe and EpiZobium angustifoZium. 

ECKENWALDER, JAMES E.* & SPENCER C.H. BARRETT. 

Department of Botany, University of Toronto, Toron- 

to, Ont., Canada M5S lAl - Phylogenetic systemat- 

ics of Pontederiaceae. 

We sought to explain the geographical distribution 

of the Pontederiaceae and the distribution of such 

features as breeding systems and chromosome numbers 

in this small, aquatic monocotyledonous family, using 

phylogenetic reconstructions. Six different methods 

of cladogram construction were applied to a data set 

embracing all 34 extant species and subspecies of the 

family. Trees resulting from the various procedures 

were compared using several optimality criteria, in- 

cluding a new measure called effectiveness. When 

treated as phylograms, a Wagner tree using all char- 

acters and presupposing a liliaceous ancestor was 

most effective (32.4%), and far more effective than a 

UPGMA-derived tree (1.0%). When treated as pheno- 

grams, and evaluated using the cophenetic correlation 

coefficient (r ), the UPGMA tree was clearly super- 

ior (r =0.8565 to the best Wagner tree (r =0.624). 

Despite numerous differences of detail, a reasonable 

consensus of many trees can be constructed. The most 

parsimonious interpretation of breeding system dis- 

tribution in Pontederiaceae treats heterostyly as a 

synapomorphy of only one lineage of the family. Mir- 

roring repeated transitions to homostyly in this 

heterostylous lineage, more than two thirds of the 

character state changes of the trees are homoplasious, 

While chromosome numbers display little homoplasy, 

geographical distributions are confusing. A vicari- 

ance explanation of the biogeography of the family, 

based on a Gondwanan distribution, seems less parsi-

monious than an origin in South America, followed by 

repeated eastward dispersals. The cladograms raise 

questions about the present classification of the 

family, but their resolution is awkward. 

ELISENS, WAYNE J. Department of Botany, Miami 

University, Oxford, OH 45056. - Systematic 

approaches to generic delimitation in Maurandya 

s. lat. (Scrophulariaceae-Antirrhineae). 

A reexamination of previous taxonomic treatments of 

Maurandya s. lat. has been undertaken using new 

information from comparative macromorphology, chromosome 

number, pollen morphology, seed coat morphology 

and anatomy, reproductive biology, crossability/fertility 

relationships, and geographic distribution. 

Evaluation of these data in a tribal context arid the 

finding of six new species have been particularly 

useful in delimiting supra-specific boundaries and 

assigninag rank. All the species are honioploid and 

share the chromosome base number x-12 which is unique 

in the tribe. The basic categories of pollen rrorphology 

(2 types), seed coat morphology (5 types), seed 

coat anatomay (2 types), and sexual organ timring/placement 

(2 types) correlate well with macromorphological 

charaecters. Artificial hybridization studies 

indicate wide interspecific cross-compatibilities 

with the vast majority of viable hybrids of intrageneric 

origin. These data and subsequent cladistic 

analyses suggest that the MaunIndyin2e is a 

monophyletic, new world group of 20 species in L; 

genera sufficiently distinct from other tribal genera 

to warrant subtribal rank. Correlation of cladistic 

branching pattern and geographic distribution suggest 

that the subtribe originated in xeric habitats of 

the southwestern United States and north-western 

Mexico; taxa have subsequerntly migrated/radiated 

al-ong the Sierra Madre Occidental to more mesic 

habitats of southern M4exico and Guatemala. 

EYDE, RICHARD H. Department of Botany, Smithsonian 

Institution, Washington, DC 20560. -- Classifying 

the Cornaceae, problems and progress. 

From reviewing what is known of Cornus and its allies 

true and false, I infer that Cornus has evolved in 

two main lines, one surviving as 30 or so closely 

linked species with blue (or white) fruits, the other 

as a more diverse group of 20 or so red-fruited 

species. Traits that go with fruit color to make the 

major split include bracted vs. bractless inflores- 

cence, size and shape of pollen, serological react- 

ions, and iridoid vs. non-iridoid glucosides. The 

red-fruited species fall into three subgroups: dwarf 

cornels, showy-bracted and disciflorous dogwoods, 

cornelian cherries. Fruits of the third subgroup are 

not always red, but all, including those of 

"Afrocrania," have distinctive cavities within the 

fruit-stone0 Blue-fruited species with small 

inflorescence bracts are nearer than any red-fruited 

ones to the ancestors of Cornus. Other authors have 

said otherwise, but much of their evidence can be 

explained away. Though Cornus links most securely 

with Nyssa and Davidia, Mastixia, with its Cornus- 

like trichomes, may have diverged from Cornus later 

on. Evidence linking Cornus to Mastixia is not as 

strong as I would like, but it is stronger than that 

linking Cornus to any other genus of the 

Pflanzenreich Cornaceae. 


FADEN, ROBERT'B. Department of Botany, Smithson- 

ian Institution, Washington, D.C. 20560. - Floral 

dimorphism, pollen dimorphism and floral biology 

in a West African Commelinaceae, Palisota hirsuta 

(Thunb.) K. Schum. 

Palisota hirsuta, a large shrubby Commelinaceae to 

4 m tall, is common in West Africa. In Ghana and 

in cultivation plants flower once a year, between 

December and June. The strongly-scented flowers, 

which are produced in large thyrses, are all simi- 

lar superficially, but on closer inspection they 

are found to be either perfect or staminate. The 

dimorphism between the two flower types is in the 

degree of development of the gynoecium and in the 

position, size and anther sac dehiscence of one of 

the stamens. Within all flowers two of the three 

polliniferous stamens produce copious amounts of 

"feeding pollen." Only one stamen -- the dimorphic 

one -- produces pollen that is capable of effecting 

fertilization. The pollen grains.from the two 

types of stamens within each flower are dimorphic. 

Although the plants are self-compatible, outcross- 

ing is enhanced by the flower structure and by the 

spatial and temporal distribution of the different 

flower types on the plant. 

FAIRBROTHERS, DAVID E. Department of Biological 

Sciences-Botany Unit, Rutgers University, 

Piscataway, NJ 08854. Serological Investigation 

of the Annoniflorae (Magnoliiflorae). 

Serological data obtained from seed meal extracts 

used in double diffusion and line immunoelectrophoresis 

experiments were analyzed by mean absorption similarity 

coefficients. Sixteen taxa belonging to the 

Annonaceae, Illiciaceae, Lauraceae, Magnoliaceae, 

and Schisandraceae were used in the analyses. 

Using unweighted pair group method analysis (UPGMA) 

dendrograms of serological similarity were generated. 

Line immunoelectrophoresis allowed direct comparisons 

of similarities and differences among various antigen 

samples in a single gel by positioning the appropriate 

samples next to each other. The analysis showed 

Illicium and Schisandra to have 92% serological similarity. 

The members of the Lauraceae revealed three 

serological groups. The descending order of serological 

similarity is as follows: Magnoliales-, 

Illiciales--- Annonales -0 Laurales. Both the 

Annonales and Laurales have approximately equal similarity 

with the Magnoliales. 

FROHLICH MICHAEL W. Department of Biological 

Sciences, Union College, Schenectady, NY 12308. - 

The common-is-primitive rule: how common is common? 

Character state polarity is sometimes evaluated by 

the common-is-primitive rule, but the reliability of 

this method has been debated. Donoghue and Madison 

(AIBS, 1982) opposed its use in outgroup analysis. 

They show that the most parsimonious character state 

assignment to the branch leading from outgroup to 

ingroup (or, equivalently, to the root of a tree) is 

extremely sensitive to exact tree topology; even a 

rare character state may be primitive. They recom- 

mend determining enough of the topology to evaluate 

the rooting character state directly. While 

desirable, this is often impractical or impossible. 

In the absence of other information, can any use be 

made of character frequency data? One may consider


all topologically distinct trees and calculate what 

percent of them root in each of the possibly prim- 

itive states. I consider strictly dichotomous trees 

with unlabeled interior nodes and n = a + b labeled 

termini representing n taxa, a of the common state 

and b of the rare state. The percents of trees 

rooting in the common, rare or equivocal states are 

% A, % B and % AB respectively. Calculations are 

made by explicit formulae (for b = 1, 2 and 3) or by 

a computer algorithm. The % A, % B, and % AB depend 

strongly on the ratio of b to n but only weakly on 

n. As b/n decreases % B declines rapidly (% B < 5% 

for b/n = .30, n < 30), % AB declines slowly and 

% A increases almost linearly. Low percent outcomes 

may often be disregarded in subsequent cladistic 

analysis without seriously increasing the overall 

chance of error. This approach may be useful 1) in 

preliminary studies, 2) in dealing with unresolved 

multichotomies within larger trees and 3) in evalu- 

ating the effects of remote outgroups in the out- 

group substitution method (Donoghue and Cantino, Ms). 

FRYXELL, PAUL A. U.S.D.A., Texas A&M University, 

College Station, TX 77843. - Floral symmetry and 

zygomorphy in the Malvaceae. 

Flowers of the Malvaceae are typically actinomorphic, 

with radial symmetry. The petals are individually 

more or less asymmetrical, giving the corolla a 

"pinwheel" appearance. The five imbricate petals may 

overlap in a left-handed or right-handed manner (i.e. 

clockwise or counterclockwise). Studies have shown 

that in most species, flowers of an individual plant 

are about 50% of each type, that is the direction of 

aestivation is random. In a few species, however, 

the direction of aestivation is evidently non-random, 

although the significance of this phenomenon is not 

clear. In typically actinomorphic malvaceous 

flowers, other flower parts (calyx, androecium, 

gynoecium) are asymmetrical--with the exception of 

the genus Abelmoschus in which the calyx splits 

laterally to an asymmetrical form; the flowers of 

Abelmoschus are otherwise radially symmetrical. A 

small number of species of Malvaceae, however, have 

developed a more or less zygomorphic (i.e. bilateral- 

ly symmetrical) form. This development of zygomorphy 

is correlated with floral presentation and is pre- 

sumably also correlated with pollinating animals, 

although observations on pollinators are scarce. In 

these cases, all flower parts (sometimes with the 

exception of the calyx) show bilateral symmetry, i.e. 

the flowers as a whole are zygomorphic. Three dis- 

tinct patterns of zygomorphy have been observed. Two 

of these have evidently occurred only once each (in 

Hibiscadelphus spp. and in Periptera sp. nov.), 

whereas the third has evidently occurred repeatedly 

in several different genera (e.g. Pavonia, Hibiscus, 

Kosteletzkya). As might be expected, zygomorphy 

tends to occur in species with relatively showy 

flowers. 

FURLOW, JOHN J. Department of Botany, Ohio State 

University, Columbus, Ohio 43210. - Evolutionary 

divergence and classification of the Alnus viridis 

complex (Betulaceae). 

Alnus viridis (s. lat .) consists of a series of geographic 

races of mostly circumpolar distribution. 

During the past century, these have been treated 

variously as subspecies of one or more species and as 

separate species (A. viridis, A. crispa, A. sinuata, 

A. fruticosa, and A. maximowiczii). The taxonomy of 

the group remains a source of disagreement today, 

though there has been a trend in recent years to view 

the complex as consisting of a single species. To 

determine the degree of morphological divergence and 

phenetic relationships among the components of the 

group, univariate and multivariate statistical pro- 

cedures, including analyses of variance, tests of 

homogeneity, cluster analyses, and discriminant 

analyses, were applied to ]20 characters of 38 OTU's 

representing geographical segments of all the taxa 

involved. With the exception of A. maximowiczii, the 

races were found to possess strong affinities among 

themselves equivalent to those existing among seg- 

ments of other species of the genus, this supporting 

the treatment of the group as one widespread species. 

Populations of the "green alder" of Alaska, British 

Columbia, Washington, and adjacent regions, which 

for many years have been treated as identical with 

A. viridis subsp. crispa (A. crispa) of boreal 

northeastern North America, are shown by the analyses 

to be divergent from subsp. crispa and instead close- 

ly allied with A. viridis subsp. fruticosa (A. fruti- 

cosa) of Siberia, suggesting their original intro- 

duction into the continent from Asia actoss the 

Bearing Strai. Subsp. crispa, on the other hand, 

shares strong similarities with A. viridis subsp. 

viridis of Europe, pointing to an eastern intro- 

duction of that group. 

FURLOW, JOHN J. Department of Botany, Ohio State 

University, Columbus, Ohio 43210. - The phylogenetic 

relationships of the genera and infrageneric 

taxa of the Betulaceae 

The Betulaceae are an ancient and diverse family distributed 

throughout the Northern Hemisphere. Their 

six genera have been combined and divided in recent 

taxonomic treatments to form a wide variety of groupings 

of separate families, tribes, genera, and infrageneric 

taxa. Often, this work has paid only cursory 

attention to critical but relatively unfamiliar 

groups, including species of several genera in eastern 

and southern Asia, and few attempts have been 

made to reconstruct its phylogeny on the basis of 

comprehensive data. In this study, 21 subgroups of 

the family have been analyzed using morphological 

characters and numerical cladistic methodology to 

obtain an estimate of their evolutionary relationships. 

The family is initially divided into two 

major evolutionary lines (tribes Betulae and Coryleae), 

and each of these includes sublines corresponding 

to the commonly recognized genera, all of 

which appear as monophyletic assemblages. Betula and 

Alnus are each comprised of several groups recognizable 

as subgenera, these being mostly broadly correlated 

with latitudinal climatic zones. In addition, 

many of the genera contain ultimate groups of 

species correlated with geographical regions and 

recognizable at the sectional level. The most complex 

relationships occur within the genus Alnus, the 

most diverse group of the family and the most unsettled 

at the infrageneric level. Here the subgenera 

are perhaps more equivalent to some of the 

genera of the Coryleae. Within Alnus, the problematical 

group containing A. maritima of eastern 

North America and A. nepalensis and A. nitida of 

Asia is shown to represent a distinct phylogenetic 

line equivalent to the other subgenera. 

GABEL, MARK 

L. Division of Science and Mathema- 

tics, Black Hills State College, Spearfish, SD 

57783. -A biosystematic study of the genus Impe- 

rata (Gramineae: Andropogoneae). 

A revision of the weedy grass genus Imperata is pro- 

posed . The present study presents the resul ts of

field and herbarium studies, supplemented by chromo- 

some numbers, leaf anatomy, and starch gel electro- 

phoresis. Morphological measurements were analyzed 

using principal component analysis and cluster ana- 

lysis. Nine species are recognized including: I. 

cy indrica, I. condensata, I. minutiflora, I. brasi- 

liensis, I. cheesemanii, I. tenuis, I. conferta, I. 

contracta, and I. brevifoTlia. 

GIANNASI, DAVID E.*, G. T. PRANCE and L. CORADIN. 

Department of Botany, University of Georgia, 

Athens, GA 30602, The New York Botanical Garden, 

Bronx, NY 10458, and Secao do Botanica, Centro 

Nacional de Recursos Geneticos, CENARGEN-EMBRAPA, 

Ave. W5 Norte (Parque Rural), Caixa Postal 102372, 

70000-Basilia-DF, 

(Chrysobalanaceae). 

Brazil. - Flavonoids in Parinari 

A survey of flavonoids in 31 Asian, African and Neotropical 

species of Parinari showed a predominance of 

flavonol glycosides based on myricetin, quercetin and 

kaempferol. The African taxa split into two groups 

based on the presence or absence of myricetin glycosides. 

The Neotropical taxa, a complex of closely 

related ecologically differentiated species are 

chemically very similar and with few exceptions lack 

myricetin as does one group of African species. The 

Asian taxa are similar to the Neotropical ones in 

their flavonoid patterns and general lack of myricetin 

glycosides. The presence of myricetin, considered 

a primitive flavonoid character, suggests 

that the African species producing these flavonoids 

represent a primitive nucleus from which a nonmyricetin 

group may have evolved giving rise by 

subsequent eastward and westward expansion to two 

myricetin-lacking phytogeographic lines. This 

hypothesis is in agreement with current proposals for 

geographic 

general. 

evolution in the Chrysobalanaceae in 

GIANNASI, DAVID E.*, G. MORTON and R. BUTA. 


Athens, GA 30602, Department of Environmental 

Sciences, University of Tennessee, Chattanooga, TN 

37403, and Department of Biological Sciences, 

Rutgers University, Newark, NJ 07102.- Chemical 

documentation 

asperula. 

of the hybrid origin of Solidago X 

A flavonoid study of Solidago X asperula in New 

Jersey was undertaken to determine if the previously 

described hybrid origin of this taxon could also be 

documented chemically. The hybrid swarm studied 

grows in a disturbed residential area along the Toms 

River. Small numbers of both parents, S. rugosa and 

S. sempervirens are found in the area along with a 

larger number of putative hybrids. Solidago rugosa 

is unique in its possession of two flavonol and two 

apigenin-C-glycosides while S. sempervirens is distinct 

in its possession of a diosmetin-7-0-diglycoside. 

The hybrids show various degrees of morphological 

intermediacy and some backcrossing to the 

parents. Likewise, hybrid flavonoid profiles are 

mostly additive confirming their hybrid origin. In 

addition, many of the hybrids produce two "novel" 

flavonoids (luteolin 7-0-mono- and diglycoside) not 

found in either parent. Their occurrence in the 

hybrids may be due to genetic disruption resulting in 

the expression of previously unsequestered intermediates 

(normally leading to diosmetin) not observed 

in the parents. Isolated stands of both parents from 

other areas do not exhiibit these hybrid compounds, 


except for one population of S. sempervirens from 

nearby Sandy Hook, suggesting that it may be a relic- 

tual population of S. sempervirens which has exper- 

ienced previous hybridization and introgression. The 

chemical data support Goodwin's earlier studies docu- 

menting the hybrid origin of S. X asperula. 

GIANNASI, DAVID E.* and KARL J. NIKLAS. 


Athens, GA 30605, and Section of Plant Biology, 

Cornell University, Ithaca, NY 14853 - 

Paleobiochemistry of the Juglandaceae. 

Leaf compression fossils of a Juglans sp., from the 

Clarkia Flora (Idaho, 22-16 x 106 KA years) were 

examined chemically and provide excellent 2D-PC 

flavonoid and hydrocarbon profiles. The fossil 

Juglans sp. is characterized by three flavonol 3-0- 

glycosides, which are found collSectively only in 

extant North American taxa (J. nigra and J. major). 

One of the fossil flavonoid markers occurs sporad- 

ically in one or two New World species of Oreomunnia, 

Carya, and Juglans, but are absent in Asian repre- 

sentatives of the latter two taxa despite suggested 

strong floristic relationships between the eastern 

United States and southern and eastern China. The 

fossil flavonoid markers occur in two species of 

Engelhardia (endemic to southern China and southeast 

Asia). Based on steroid and other hydrocarbon 

constituents, the Juglandaceae may be separated into 

two groups: Alfaroa, Oreomunnia; Engelhardia, and 

Juglans and Carya. Although the morphology and 

flavonoid chemistry of the fossils suggest a more 

immediate relationship to extant North American 

taxa, the occurrence of the three "marker" compounds 

in Engelhardia may represent only a biosynthetic 

parallel at the generic level. 

GILMARTIN, AMY JEAN * and KAREN SIMMONS. Department 

of Botany, Washington State University, 

Pullman, WA 99164-4230. - Phylogenetic analysis 

in Umbelliferae: 

Lomatium. 

I. putative sister groups to 

Umbelliferae includes about 275 genera, of which 

Lomatium is the largest western North American 

genus. In order to polarize characters for a 

cladistic analysis of Lomatium species, we sought 

to identify sister taxa from among 11 genera putatively 

close to Lomatium. Using Pastinaca as an 

outgroup to the 11 genera, up to 15 characters 

could be polarized. Trees and networks were generated 

manually and with computer programs. 

Prionosciadium, Cymopterus and Peucedanum were 

identified as likely sister taxa. These and other 

combinations of genera were used to polarize 

characters for a study of the 73 species of Lomatium 

in part II. 

GILMARTIN, AMY JEAN and KAREN SIMMONS *. Department 

of Botany, Washington State University, 

Pullman, WA 99164-4230. - Phylogenetic analysis 

in Umbelliferae: II. species of Lomatium. 

Lomatium includes about 73 species unique to western 

North America. The genus has traditionally been a 

difficult group because of the large number of 

species and the high degree of vegetative uniformity 

among them. Consequently, no sections or infrageneric 

groups have been formally recognized and no 

phylogeny of the entire group has been proposed;


Our goal was to use Hennigian cladistic methods to 

determine monophyletic groups of Lomatium species, 

as well as the relationships among groups. Sister 

taxa to Lomatium identified in the generic analysis 

were used to polarize characters pertinent to 

Lomatium. Phylogenies were constructed and puta- 

tively monophyletic groups of species were iden- 

tified. These support, in part, an earlier phenetic 

study that identified a group of 12-16 species 

having one oil tube in the intervals of mature 

fruits and two on the commissure. 

GOULD, JOYCE* and JOSEF SVOBODA. Department of 

Biology, Erindale College, University of Toronto, 

Mississauga, Ontario. L5L lC6. 

-Vegetation and Floristics of the Lake Hazen area, 

Northern Ellesmere Island. 

The Lake Hazen area is situated on northern Ellesmere 

Island in the Canadian Arctic Archipelago at 81049'N, 

71 018'W. The vegetation and flora of the area is 

diverse compared to other areas on Ellesmere Island. 

Vegetation of the lowland consists of a number of 

plant communities distinct from those of the higher 

elevations due to differences, in part, of moisture 

and substrate. The flora is rich with approximately 

115 species recorded (Savile, 1964) compared to 49 

species for the western Queen Elizabeth Islands 

(Savile, 1961). Several additional species were 

recorded in 1982 including Draba glabella Pursh 

and Sagina intermedia Fenzl. These collections 

represent extensions of the northern part of the 

range of both species. This work was supported by 

N.S.E.R.C. and the Ministry of Colleges and 

Universities (Ontario) and the University of 

Toronto. 

HALL, DAVID W. 209 Rolfs Hall, University of 

Florida, Gainesville, FL 32611. 

- Florida grass habitats. 

Grasses comprise a significant portion of the vege- 

tation of Florida and make up about one-seventh of 

the species of flowering plants in the state. They 

occupy diverse habitats and predominate as the nat- 

ural ground cover over large areas. Tolerance or 

lack of tolerance to moisture and soil type and to 

competition from other plant species influence the 

presence of certain grasses in different vegetation- 

al communities. Wet coastal marshes, inland prai- 

ries (savannas), swamps, and flood plains support 

grasses tolerant of high levels of moisture; on the 

other hand, the sandy flatwoods dominated by pine 

and saw palmetto, and the pine-turkey oak ridges, 

support the growth of drought resistant forms. 

Grasses introduced or favored by man--pastures, 

roadsides, lawns and golf course turf--must be con- 

sidered in any comprehensive discussion of the hab- 

itats.of Florida grasses as a whole. 

HARTMAN, RONAID L. Department of Botany, 

University of Wyoming, Laramie, WY 82071. - Two 

novelties in the Umbelliferae from the central 

Rocky Mountains. 

Recent studies on Rocky Mountain umbels have led to 

the recognition of two undescribed species. The 

first, from the Lost River and Lemhi ranges of 

central Idaho, was initially collected by Ray Davis 

in 1940 and confused 

Cymopterus nivalis. 

with the more southern 

The second novelty, secured 

first by Frank Tweedy in 1900 in a post-fruiting 

stage, has been confused with Oreoxis alpina from the 

Southern Rockies. Only recently was it rediscovered 

and flowering and fruiting material obtained. It is 

now known to be relatively frequent in the southern 

half of the Big Horn Mountains of Wyoming. Both taxa 

are restricted to calcareous or dolomitic substrates 

and have a chromosome number of n = 11. They are 

tufted, acaulescent herbs with yellow flowers. The 

fruits, which are terete in cross section, have 

prominent dorsal and intermediate ribs whereas the 

lateral nerves are winged. Affinities appear to be 

with Cymopterus which has been characterized, in 

part, by well-developed wings on all the nerves. A 

recent survey of the fruits of Cymopterus sensu lato 

indicates that the surface wings have been lost in at 

least four separate lines. Consequently, the 

inclusion of these new species within Cymopterus 

would not modify drastically the generic circum- 

scription. 

HAUBER, DONALD P.* and R. C. JACKSON. Department 

of Biological Sciences, Texas Tech University, 

Lubbock, TX 79409. - Evidence for autopolyploidy 

in Helianthus ciliaris DC. 

Helianthus ciliaris is a widespread perennial weed 

found throughout the Southwest and parts of Mexico. 

Recently, it has been revealed that H. ciliaris is 

a complex composed of two ploidy levels, a tetraploid 

(n = 34) and a hexaploid (n = 51). Meiotic samples 

were collected from both tetraploid and hexaploid 

populations and analyzed quantitatively as to the 

frequency of the different configuration types at 

diakinesis. In the case of the tetraploids all 

individuals from all populations sampled demonstrated 

chromosome pairing behavior as expected according to 

the autotetraploid model. However, the status of 

the hexaploid is unknown at this time. Evolutionary 

implications 

discussed. 

concerning the tetraploid will be 

HAUSER, LARRY A. Department of Botany, 

University of Illinois, Urbana, IL 61801 - 

Phylogenetic relationships and phenetic 

similarities among species of Thelypodiopsis 

and Thelypodium (Brassicaceae). 

The 36 species currently classified in either 

Thelypodiopsis or Thelypodium were studied with 

regard to interspecific relationships and generic 

delimitation. The boundary between the two genera, 

like many other closely related Brassicaceae genera, 

is indistinct and somewhat arbitrary. Thirty-five 

primarily morphological and anatomical characters 

were evaluated for each of the species examined. 

Phylogenetic (Wagner) trees were constructed with 

Stanleya, Warea, and Romanschulzia considered 

probable outgroups. In addition, phenetic 

similarities were studied using cluster analysis and 

PCA with a directed nearest neighbor network. 

Results indicate that Thelypodiopsis does not 

represent a distinct monophyletic group and must be 

either subdivided or possibly combined with other 

genera such as Thelypodium and Caulanthus. The 

"Hesperidanthus" species, for example, represent a 

distinguishable group, but their recognition at the 

generic level would necessitate further subdivision 

of Thelypodiopsis. Within Thelypodium, as currently 

delimited, three subgenera, as described by 

Al-Shehbaz, were recognized. The implications of 

the recent removal of Rollinsia paysonii from 

Thelypodium for several other species were also 

considered.

HELLQUIST, C. BARRE. Department of Biology, 

North Adams State College, North Adams, MA 01247. 

- Observations on Potamogeton hillii in North 

America. 

Potamogeton hillii has been considered as either a 

rare or endangered species in all states and 

provinces where it occurs and is currently under 

review by the United States Fish and Wildlife Service 

for possible listing under the Endangered Species Act 

of 1973. Prior to 1960 it was collected at 22 

localities. Since 1970, 57 new areas have been 

located. This species is almost exclusively found in 

regions of limestone bedrock throughout its range. 

Presently it is most abundant in western New England 

and northern Michigan. During 1982 it was relocated 

in Connecticut and Ohio. Potamogeton hillii appears 

to be spreading its range in the limestone regions 

where it presently occurs. It is usually found in 

clear, cold water of small streams, farm ponds, and 

beaver ponds which have muddy bottoms. Contrary to 

the literature, winter buds are extremely common, 

being formed late in the season. The abundant winter 

buds and fruit produced help guarantee the continued 

spread of this species. More localities should be 

looked for near existing and previous sites as long 

as they are within the limestone region. 

Potamogeton hillii should not be considered for 

protection nationally and should be omitted from 

consideration in the states where locally abundant. 

* 

HELLQUIST, C. BARRE and ROBERT L. HILTON 

Department of Biology, North Adams State College, 

North Adams, MA 01247. Environmental Science 

Program, University of Massachusetts/Boston, 

Boston, MA 02125. - The taxonomic status of 

Potamogeton lateralis (Potamogetonaceae) from 


Potamogeton lateralis, one of the rarer pondweeds in 

North America is a dimorphic species that bears 

flowers on plants with emersed leaves and fruit on 

separate plants that produce submersed leaves only. 

This pondweed is similar to P. vaseyi which produces 

flower and fruit on plants with floating leaves. Two 

populations of P. lateralis have been studied in New 

England. In both cases P. lateralis did not occur 

in the same location during two consecutive years. 

Instead, during the second year, typical P. vaseyi 

was present. Chemotaxonomic studies involving 

flavonoids of P. lateralis, both fertile and sterile, 

P. vaseyi, and fertile P. pusillus var. tenuissimus 

have shown that P. lateralis as previously described 

is actually a composite of the former two species. 

Most of the type specimens observed contained only 

sterile plants with floating leaves. Fertile 

material on the type sheets proved to be P. pusillus 

var. tenuissimus. Therefore, the taxon was described 

from two elements, P. vaseyi and P. pusillus var. 

tenuissimus. The P. vaseyi element appears to form 

a juvenile stage which takes on the characteristics 

of P. lateralis as described in the literature, but 

this stage is a transient stage which persists for 

short periods of time. 

HILS, MATTHEW H. *, TERRY W. LUCANSKY, AND WILLIAM 

LOUIS STERN. Department of Botany, University 

Florida, Gainesville, FL 32611. - Comparative 


anatomy and systematics of woody Saxifragaceae: 

Cuttsia viburnea F. v. Muell. 

The purpose of this work is to provide vegetative 

anatomical and morphological data, especially wood 

anatomy, for the monotypic genus Cuttsia, and to use 


these data to determine the taxonomic position of 

Cuttsia within the Saxifragaceae sensu lato. Cuttsia 

viburnea F. v. Muell. is a shrub or small tree endem- 

ic to southeast Queensland and northeast New South 

Wales, Australia. It possesses simple, ovate, ser- 

rate leaves in an alternate phyllotaxy. The nodal 

pattern is trilacunar, three-trace, with the three 

traces fusing in the petiole to form one large, med- 

ullated, concentric petiolar strand. The midvein 

also is a concentric bundle in the basal half of the 

lamina and becomes a collateral bundle toward the 

apex of the leaf. The adaxial epidermis is biseri- 

ate, and the abaxial epidermis is uniseriate. Sto- 

mata occur only on the abaxial epidermis, and the 

stomatal apparatus is anomocytic. Mesophyll con- 

sists of biseriate palisade and spongy layers. The 

wood lacks growth rings and possesses numerous, 

mostly solitary, circular to oval pores. Perfora- 

tion plates are scalariform with numerous bars per 

plate. Intervascular pitting is opposite to alter- 

nate. Thick-walled tracheids, occasionally with 

spiral thickenings, are present. Diffuse apotracheal 

parenchyma is common but not abundant. Vascular rays 

are uniseriate, homocellular and multiseriate, heter- 

ocellular. Ray tissue is abundant. Cuttsia viburnea 

possesses most of the characteristics of the archety- 

pical woody saxif rage, and the distinctive petiolar 

vasculature is similar to that in Forgesia borbonica 

Commers., a Mascarene Islands endemic. 

HOLLOWELL, VICTORIA C.* and THOMAS R. 

SODERSTROM. Department of Biology, 

University of South Carolina, Columbia, 

S.C. 29208, and Department of Botany, 

Smithsonian Institution, Washington, D.C. 

20560. - Re-examination of the genus 

Eremitis oceae Bambusoideae). 

The neotropical genus Eremitis was erected 

in 1877 by Doell to encompass the single 

herbaceous bambusoid species E. monothala- 

mia. Tutin in 1936 merged Eremitis into the 

related, more extensive genus Pariana; but 

Calderon and Soderstrom in 1980 reinstated 

the genus with the single species E. parvi- 

flora(=monothalamia). Re-evaluation of 

morphological, anatomical and field data in 

combination with observations on numerous 

recent collections supports the view that 

Eremitis is distinct from Pariana. Three 

new species have been discovered in Brazil- 

ian coastal rain forests: E. glabra and E. 

robusta from Bahia and E. breviglumis from 

Espirito Santo. Cleistogamous subterranean 

inflorescences as well as multiple inflores- 

cences on each aerial culm characterize this 

interesting assemblage. Striking dimorphism 

of the spikelet whorls within each inflores- 

cence and reduction in stamen number from 

six or more to only two further distinguish 

the genus. Preliminary diploid chromosome 

numbers of 67 or 68 for E. breviglumis, 86 

for E. robusta and 92 for E. parviflora are 

substantially greater than any yet reported 

in Pariana or other Bambusoideae. Re-def- 

inition of Eremitis to include E. parviflora 

and the newly recognized species is proposed. 

HUCK, ROBIN B. Department of Botany, University 

of North Carolina, Chapel Hill, NC 27514 - 

Clarification of the generic limits of Dicerandra 

(Labiatae) by hybridization experiments. 

An u~nderstanding of the systematic~s of Dicerandra 

pivots on a resolution of the relationship between


the two most widely distributed, but morphologically 

distinct, species in the genus: D. linearifolia and 

D. odoratissima. The former species which is the type 

for the genus has exserted stamens and a geniculate 

corolla tube with the upper limb flaring to a stand- 

ard; the latter, inserted stamens and a tubular cor- 

olla with the upper limb cucullate. Should D. 

odoratissima be retained within the genus? Onie 

author, as recently as 1982, has suggested that these 

two are reproductively isolated and that D. odorat- 

issima could be raised to a generic level. Data from 

field and breeding studies accumulating since 1979 

add new insights. Six hundred forty interspecific 

crosses were attempted on 110 plants collected from 

16 populations throughout the species' range in the 

southeastern United States. Out of 2560 possible 

nutlets (4 per cross), 306 nutlets produced mature 

flowering plants. Flowers of interspecific F hy- 

brids consistently showed characters intermediate to 

the parents. A count of 37,177 pollen grains of 

these F1s indicate a viability of 84% overall. 

Pollen viability of F s of sympatric oarental species 

rose to 92.5% as compired with 78.6% for F s of 

allopatric parentals. A count of 5029 graIns of 

the F showed a viability of 75.0%. The subsequent 

discohery and analysis of a natural hybrid swarm 

coupled with the above data suggest a close genetic 

relationship with gene exchange occurring in sym- 

patric areas between D. linearifolia and D. odorat- 

issima. While a degree of reproductive isolation is 

ac nowledged, the retention of D. odoratissima within 

Dicerandra is upheld. 

JACKSON, R. C. Department of Biological Sciences, 

Texas Tech University, Lubbock, TX 79409-4149 

- Gametic selection as a possible isolating 

mechanism in chromosomal races of Haplopappus 

gracilis. 

Controlled crosses have been made between the n = 2 

Dibivalens and the n = 3 tribivalens races. Reci- 

procal F hybrids of the two chromosomal races have 

been use[ to produce F2 and bacross generations. 

Seeds from such crosses can be germinated easily, and 

standard methods can be employed to determine possi- 

ble karyotypes with 2n = 4, 5, and 6 chromosomes. 

Equal numbers of n = 2 and n = 3 sperms and eggs are 

produced from 2n = 5 F1 hybrids because of prefer- 

ential disfunction of a trivalent so that 2 small, 

acrocentric chromosomes always go to one pole with a 

nucleolar organizing chromosome, and the larger 

metacentric from the trivalent goes to the other pole 

with a N.O. chromosome. Data obtained thus far show 

that when equal numbers of n = 2 and n = 3 pollen 

grains are applied to 2n = 4 stigmas the n = 4 

pollen grains are more successful. Conversely, when 

an equal mixture of n = 2 and n = 3 pollen grains are 

brushed on a 2n = 6 stigma, the n = 3 pollen grains 

are more successful. If these same mixtures are 

applied to 2n = 5 hybrid stigmas, equal numbers of 

the two chromosomal types of pollen are involved in 

fertilization. The differential gametic success of 

fertilizing the eggs from homokaryotypes with the 

same karyotype appears to ba a partial isolating 

barrier when the two races come into contact. 

JACOBS, BRIAN F., CHARLES R. WERTH, AND SHELDON I. 

GUTTMAN*. Department of Botany and Department of 

Zoology, Miami University, Oxford, Ohio 45056. 

- Genetic relationships in Abies (fir) of eastern 

U.S.: an electrophoretic study. 

Abies (fir) is widely considered 'to consist of two 

species in the eastern U.S., A. balsamea (L.) Mill. 

and A. fraseri (Pursh.) Poir., distinguished by rela- 

tive cone bract to subtending cone scale lengths and 

number of leaf hypodermal cells. Intermediate indi- 

viduals have been recognized as A. balsamea var. 

phanerolepis Fern. An understanding of the relation- 

ship between the two presumptive species over the 

last 18,000 years hinges on the interpretation of the 

intermediate. Two alternative hypotheses view the 

intermediate as either an interspecific hybrid or an 

intraspecific variant. Twenty gene loci were elec- 

trophoretically analyzed in population samples from 

all three taxa in an attempt to resolve the system- 

atic relationships of Abies from the eastern U.S. 

Cluster analysis failed to group populations into the 

three recognized taxa. All populations and taxa 

shared similar complements of alleles at comparable 

frequencies for 13 polymorphic loci. Genetic dis- 

tances among populations ranged from 0.103 to 0.O. 

These data support a conspecific status for all of 

eastern U.S. Abies and suggest intermediate fir is 

not of hybrid origin. Our results are consistent 

with those of recent studies which conclude that A. 

fraseri and A. balsamea are only recently (18,000 

years) diverged taxa. 

JANSEN, ROBERT K.* and NEIL A. HARRIMAN. 

Department of Botany, Ohio State Univer- 

sity, Columbus, OH 43210 and Department 

of Biology, University of Wisconsin- 

Oshkosh, Oshkosh, WI 54901. -Numerical 

taxonomic studies of the Juncus biflorus- 

J. marginatus species pair. 

The Juncus biflorus-J. marginatus complex 

comprises a morphologically variable species 

pair common throughout the eastern United 

States and occurring as far south as Argen- 

tina. Historically these two taxa have been 

treated as distinct species. A number of 

morphological features, especially culm 

diameter, number of leaves per stem, number 

of veins per leaf and width of leaves, 

inflorescence height, number of glomerules 

per inflorescence, number of flowers per 

glomerule, anther persistence, and seed 

characteristics have been used to separate 

them. Overlap in these features, however, 

has caused difficulty in recognizing these 

taxa throughout their ranges. To aid in 

understanding the patterns of morphological 

variation and to resolve the taxonomic 

limits of these two taxa, a detailed numer- 

ical taxonomic study of J. biflorus and J. 

marginatus was initiated. Fourteen charac- 

ters were measured for several hundred 

populations, and the data were subjected to 

clustering, principal components, and 

discriminant analyses. The results support 

the merger of the two taxa into a single 

variable species. 

JENSEN, RICHARD 

J. Department of Biology, Saint 

Mary's College, Notre Dame, IN 46556.-Cladistics 

of eastern North American red oaks:testing Tre- 

lease' e hypothesis. 

In his classic monograph of the American oaks (Mem. 

Nat . Acad . Sci. 20: 1-255), William Trelease pre- 

sented a scheme of phylogenetic relationships among 

the taxa he recognized. Although he doubted the ac- 

curacy of the ent ire scheme, Trelease was conf ident 

of the relationships depicted for the better studied

groups. Among the latter were the taxa of red and 

black oaks of eastern North America. Trelease's 

scheme was based on "fundamental characters," though 

he did not specify which, and on the assumption that 

his serial groups (e.g., Coccineae) reflected natural 

groups. I have been examining patterns of character 

state distribution among these oaks and have come to 

the conclusions that (1) some of Trelease's serial 

groups are not definable by the characters I have 

employed and (2) his scheme of phylogeny is incon- 

gruent with either a maximum parsimony or maximal 

clique analysis. Specifically, series Coccineae, 

Laurifoliae, and Marilandicae appear to be polyphy- 

letic or paraphyletic assemblages. While much addi- 

tional work needs to be done, the results presented 

suggest either that these taxa are not a monophyletic 

group or that there is a vast amount of homoplastic 

evolution in the characters analyzed. 

JOHNSON, MILES F. Department of Biology, 

Virginia Commonwealth University, Richmond, VA 

23284 - SEM Palynology of Ageratum L. 

Ageratum L. (Eupatorieae -- Asteraceae) consists of 

approximately 43 species wlhich occur in Mexico, 

Central America and South America. Ageratum 

conyzoides is a pantropic weed. Johnson, in 1971, 

and King and Robinson, in 1972, have studied the 

taxonomy of the genus but the ultrastructure of the 

pollen has not been investigated. Pollen of more 

than half of the taxa was examined by SEMo The 

pollen is tricolporate, echinate and commonly 

spherical, but spherical and prolate grains in a 

single specimen of A. corymbosum are noted. The 

colpus is usually deeply incised and often out- 

lined by the exine which may be granular, warty, 

rugose or bear irregular patches. The echinae are 

usually porous; some bear longitudinal ridges. 

Though the pollen is basically uniform, there are 

surface variations which tend to support the 

taxonomy of the recent investigators. 

KEIL, DAVID J. Department of Biological Sciences, 

California Polytechnic State University, San Luis 

Obispo, CA 93407. - Biogeography of Pectis (Aster- 

aceae) in the West Indies. 

Caribbean basin biogeography of Pectis reflects a 

history of dispersal, differentiation and polyploidy. 

Approximately twenty species of Pectis occur in the 

West Indies and peninsular Florida. Most occupy more 

than one island (often several) that are separated by 

deep-water barriers. Five of the taxa represent wide 

ranging species with large mainland distributions in 

Mexico, Central America or South America. The remain- 

der are endemic to the West Indies or have marginal 

distributions in mainland areas. All Pectis taxa in 

the West Indies appear to be self-compatible. The 

achenes are very small and bear a well-developed 

pappus. Eight of the thirteen taxa for which 

chromosome counts have been determined are poly- 

ploids with the 4x, 6x and 8x levels represented. 

In contrast only seven of 51 mainland taxa counted 

to date are polyploid, and two of these are also 

represented at the diploid level. 


KEIL, DAVII J. Department of Biological 

Sciences, California Polytechnic State 

University, San Luis Obispo, CA 93407 - 

Chance convergence and the identity of 

Pectis linearifolia (Asteraceae). 

The Pectis linearifolia "complex" of penin- 

sular Florida comprises two morphologically 

similar endemic "taxa". Pectis linearifolia 

Urban is an apparently sexual tetraploid 

species (2n = 4x = 48) from mid-peninsular 

regions. Foliar glands in this species 

contain lemon-scented oils. In south penin- 

sular Florida morphologically very similar 

sterile triploids (3n = 36) occur together 

with P. prostrata Cav. (2n = 24) and P. lep- 

tocephala (Cass.) Urban (2n = 48) , both of 

which are apparently sexual species. Both 

P. lep-ocephala and the triploids have 

"spicy-scented" oils; P. prostrata is not 

scented. The triploids and-P. prostrata 

both form an achene complex in which the 

phyllaries and all the enclosed achenes fall 

together as a unit at maturity. This 

feature is lacking in P. leptocephala and P. 

linearifolia (s.s.). The triploids are 

apparently F-1 hybrids between P. prostrata 

and P. leptocephala that by chance closely 

resemble P. linearifolia. Despite their 

considerable morphological similarity, P. 

linearifolia and the triploids have apparent- 

ly originated independently and are taxono- 

mically distinct. 

KOLTERMAN, DUANE A.* and ROBERT R. KOWAL. 

Department of Botany, University of Wisconsin, 

Madison, WI 53706. - The origin of hexaploid 

Senecio pseudaureus var. semicordatus (Aster- 

aceae, Senecioneae): the bearing of flavonoid 

chemistry and morphological data. 

Senecio pseudaureus Rydb. var. semicordatus 

(Mack. & Bush) T. M. Barkley is found in the 

central United States and adjacent Canada, from 

Manitoba through the Dakotas, Minn., Wis., Iowa 

and Nebr. to Kan. and Mo. Chromosome counts 

indicate that the taxon is composed of two races, 

a diploid (n=23) in the north and an approximate 

hexaploid (n=ca. 69) in the south. Flavonoid 

data, obtained from greenhouse-grown plants, show 

that hexaploids from Mo. (3 populations) are 

chemically very similar to northern diploids (9 

populations from N. and S. Dak., Minn., Wis., 

and Iowa) and, therefore, are probably autohexa- 

ploids. A Kansas population of hexaploids assign- 

able to var. semicordatus, on the other hand, 

appears to represent a hybrid swarm, with much 

contamination from an adjacent population of S. 

plattensis Nutt., a widespread tetraploid species 

(n=46) of the Great Plains with scattered occur- 

rences eastward. The Kansas hexaploids are 

chemically both variable and intermediate between 

var. semicordatus (diploid and hexaploid) and S. 

plattensis. The flavonoid data are supported by 

both field observations and morphological data 

from plants grown in transplant gardens in Madi- 

son, Wis.: the Missouri hexaploids are similar 

to northern diploid var. semicordatus, while the 

Kansas hexaploids are intermediate between these 

and S. plattensis. Autopolyploidy and hybridiza- 

tion are common in the S. aureus complex; flavo- 

noid chemical and morphological data clearly indi- 

cate that S. pseudaureus var. semicordatus, as 

well, shares both propensities with its allies.


KOWAL, ROBERT R. and DUANE A. KOLTERMAN.* 


Madison, WI 53706. A measure of dissimilarity 

for multivariate binary (presence/absence) data 

with examples of its use on biochemical data 

from Cnidoscolus (Euphorbiaceae) and Senecio 

(Asteraceae). 

As a measure of dissimilarity between two groups, 

A and B, we use the average number of compounds 

by which they differ, nAB, an extension of a sim- 

ple count of the number of compounds by which 

two individuals differ to two groups of individu- 

als. For all possible pairs of individuals, one 

from each group, one can count the number of 

compounds by which the two individuals differ. 

The measure is the average of all such counts and 

can be calculated with the equation 

p 

nAB = X (ai + bi - 2aibi) 

where p is the total number of compounds ob- 

served and ai and bi are the frequencies of com- 

pound i in groups A and B, respectively. The 

average number of compounds by which a group 

differs from itself, nAA, also provides a measure 

of variability within groups which can be used 

directly to evaluate the relative sizes of differ- 

ences between groups; it equals twice the sum of 

the variances of the presences and absences of 

each compound. The measure is used on flavonoid 

data from Cnidoscolus (Euphorbiaceae) and Senecio 

(Asteraceae); metric multidimensional scaling pro- 

vides a two- or three-dimensional representation 

of the distance matrix. Two more familiar mea- 

sures of dissimilarity--squared Euclidean distance 

and Manhattan distance--give similar representa- 

tions of relationships among groups. We prefer 

nAB because it is intuitively reasonable and pro- 

vides a measure of error variability. 

LAMMERS, THOMAS G.* ROGER W. SANDERS, DANIEL J. 

CRAWFORD, H.-D. BEHNKE, TOD F. STUESSY, and 

MARIO SILVA 0. Department of Botany, Ohio State 

University, Columbus, OH 43210; Fairchild 

Tropical Garden, Miami, FL 33156; Zellenlehre, 

Universitat Heidelberg, West Germany; and 

Departamento de Botanica, Universidad de 

Concepcion, Chile. - Cytology, flavonoid 

chemistry, ultrastructure, and systematic relationships 

of Lactoridaceae. 

The angiosperm flora of the Juan Fernandez Islands 

contains one endemic family, the Lactoridaceae, 

with a single species, Lactoris fernandeziana. The 

family is in serious danger of extinction. Only 5 

individuals in 3 populations were encountered during 

2 expeditions in 1980 to the largest island, 

Masatierra. Study material was collected from portions 

of these individuals. Five leaf flavonoids 

have been identified: three kaempferol 3-0-glycosides 

and two isorhamnetin 3-0-glycosides. The 

chromosome number is n=20. TEM observations of 

sieve elements reveal S-type plastids. The 

morphological relationships of the Lactoridaceae 

place it clearly within the Magnoliidae, the most 

primitive subclass of dicotyledons. Its restriction 

to Masatierra, which geologically is only 4 million 

years old, suggests that the family originated 

elsewhere and previously had a much wider distribution. 

Extinction has apparently el iminated al l 

populations except those now endemic to the Juan 

Fe rnandez Is lands . 

LANDON, JAMES*, MARGARET R. BOLICK and MICHAEL 

R. VOORHIES. Divisions of Botany and Vertebrate 

Paleontology, University of Nebraska State 

Museum, Lincoln, NE 68588-0514. - Medial Miocene 

paleoecology of Nebraska. 

A new method of paleoecological analysis, based on 

Carlquist's work on the ecology of xylem structure 

(Carlquist, 1977), is applied to fossil wood from the 

medial Miocene (12 to 14 million years old) of 

Nebraska. The fossil wood samples are from several 

localities in the Valentine Formation with most of 

the samples coming from the Crookston Bridge Member, 

a unit rich in vertebrate fossils. The values for 

Calquist's vulnerability index of the fossil wood are 

similar to those of the modern woody flora of 

Nebraska. The climatic indications from the fossil 

wood agree with MacGinitie's (1962) conclusions from 

the Kilgore leaf and pollen flora (als6 from the 

Crookston Bridge Member in northern Nebraska) that 

the climate then was warm temperate to subtropical 

and relatively dry, bordering on subhumid. Most 

fossil vertebrate assemblages from the lower 

Valentine Formation are dominated by grazing ungulates 

but also contain a larger number (16) of browsing 

genera than any higher stratigraphic levels. 

This gives an unusually detailed picture of the mid- 

Miocene upland pine-oak savanna and floodplain 

forests 

America. 

that preceded the grasslands in central North 

LEE, GREGORY J. Department of Botany, University 

of California, Davis, California 95616. - A biosystematic 

study of Phacelia marcescens, Phacelia 

stebbinsii and Phacelia quickii (Hydrophyllaceae). 

Phacelia marcescens Eastw. ex Macbr., P. stebbinsii 

Const. and Heckard, and P. quickii J. T. Howell form 

a group of three closely related species. Previous 

treatments have emphasized the similarity of P. marcescens 

and P. quickii. P. stebbinsii was first described 

in 1970, at which time it was likened to P. 

quickii. A systematic investigation of the three 

taxa has revealed that-P. stebbinsii is more closely 

related to P. marcescens as judged by a number of 

morphologic characters: calyx size and shape, pollen 

color, leaf morphology, fruit shape, and method of 

seed dispersal. Additionally, P. quickii does not 

hybridize with either P. marcescens or P. stebbinsii, 

whereas P. marcescens and P. stebbinsii hybridize if 

P. marcescens is the carpellate parent. The Fl and 

F2 progeny are fully fertile. At present, P. marcescens 

and P. stebbinsii are known to differ only in 

flower color and in the number of seeds produced per 

fruit. Their distinctness is maintained by the following 

isolating mechanisms: (1) geographic isolation, 

(2) unilateral crossability, and (3) an intraspecific 

advantage of P. marcescens pollen. An examination of 

the taxonomic characters which distinguish these 

three species indicates that several are part of an 

adaptive complex related to seed dispersal and seedling 

establishment. The relationship of calyx size 

to fruit weight in these three species, and in related 

species groups, indicates that the sepals are 

important photosynthetic organs. 

LEE, GREGORY J. Department of Botany, University 

of California, Davis, California 95616. - The 

systematic and ecological significance of calyces 

in the Phacelia humnilis group (Hydrophyllaceae). 

The Phacelia humilis group (Hydrophyllaceae) is an 

assemblage of approximately thirty annual taxa. The

calyces of these plants provide useful taxonomic 

characters. Of particular significance are the size 

and shape of the calyces, the variation between se- 

pals within a calyx, and the amount of accrescence. A 

survey of the species complexes within the P. humilis 

group shows that for closely related taxa a larger 

calyx is correlated with a larger fruit. This corre- 

lation was investigated and found to be statistically 

significant at the species level, at the population 

level within a species, for individuals within a pop- 

ulation, and for fruits from individual plants. Ex- 

perimentally, it was determined that the relationship 

is not due to allometry, indicating that it has func- 

tional significance. The hypothesis that the sepals 

are important photosynthetic organs was tested by 

growing plants without leaves. These plants flowered 

and produced viable seed solely on stem and sepal 

photosynthate. Sepal size variation within a calyx, 

pedicel length, and compactness of the inflorescence 

represent an adaptive syndrome which decreases the 

self-shading of photosynthesizing floral parts. 

LEMKE, DAVID E. Department of Botany, University 

of Texas, Austin, Texas, 78712. - Lignified tri- 

chomes as taxonomic characters. 

Trichomes have long been recognized as being of im- 

portance in comparative systematic investigations. 

One type which has received scant attention, however, 

is the lignified trichome. These can be easily iden- 

tified by their staining reaction in Azure B and may 

prove to be of diagnostic value because of their re- 

stricted occurrence among flowering plants. A survey 

of the literature reveals that they are known only 

from the Hernandiaceae, Cistaceae, Flacourtiaceae, 

Turneraceae, Symplocaceae, Simaroubaceae, Lamiaceae, 

and Dipsacaceae. The presence of unicellular ligni- 

fied hairs on the young stems, leaves, and calyces of 

Neopringlea (long considered to be of uncertain af- 

finities) provides additional evidence for placing 

this genus in the Flacourtiaceae. 

LEMKE, DAVID E. Department of Botany, University 

of Texas, Austin, Texas, 78712.- Tribal redefini- 

tions in Flacourtiaceae. 

The Flacourtiaceae is a large tropical family which, 

because of its polythetic nature, has developed a 

reputation as a taxon in which to place many genera 

of uncertain affinities. The most recent treatment 

of the family is that of Hutchinson, but while his 

classification is in many respects an improvement on 

those of earlier workers, it still contains a number 

of disparate elements. In the present study the 

tribes Scolopieae, Homalieae and Prockieae are rede- 

fined on the basis of morpholoqical and anatomical 

data and become much more homogeneous elements. 

Hutchinson's tribe Banareae is here dismantled; the 

genera Banara and Pineda are placed in the Prockieae, 

Trimeria in the Homalieae, and the anomalous genus 

Asteropeia transferred to the Theales. 

LERSTEN, NELS R. Department of Botany, Iowa 

State University, Ames, Iowa 50011. -Taxonomic 

and evolutionary significance of embryo suspensor 

distribution in Leguminosae. 

Embryo suspensors in the Leguminosae have long been 

known to exhibit a range of size and shape that 


approximates the variation found in angiosperms as 

a whole. Until now, no attempt has been made to 

seek any coherent patterns among legume suspensor 

diversity. I have collated about 200 published 

descriptions according to the most recent classifi- 

cation scheme for the family. Taxa represented 

include Mimosoideae (12 genera, 21 species), 

Caesalpinioideae (7 genera, 9 species), and 

Papilionoideae (about 65 genera, 150 species). The 

first two subfamilies are mostly suspensorless 

whereas suspensors usually occur in the latter. 

They are mostly inconspicuous in the putatively 

primitive and intermediately placed tribes, as well 

as in some advanced tribes. Other advanced tribes 

have conspicuous suspensors of diverse form which 

are of taxonomic significance, for example, in 

Loteae/Coronilleae, Crotalarieae, and Genisteae. 

A unique 4-celled, multinucleate suspensor occurs 

uniformly among Vicieae but nowhere else. Large 

and/or bizarre suspensors are clearly a derived 

feature in Leguminosae; suspensor variation supports 

the evolutionary trends in the family postulated on 

othe- evidence. Such comparative knowledge also 

helps to place into perspective the results of 

recent intensive studies on the Phaseolus suspensor. 

LES, DONALD H. Department of Botany, The Ohio 

State University, Columbus, Ohio 43210. 

- Taxonomic implications of aneuploidy and 

polyplo'idy in Potamogeton (Potamogetonaceae). 

A synoptic study of chromosome number reports for 73 

species of Potamogeton presents evidence supporting 

the conclusion that the genus is characterized by 

two different polyploid lineages (one based upon x=7 

and the other upon x=13). Analyzed comparatively, 

chromosome numbers also indicate that the diploid 

level of the genus is 2n=14, and that the x=13 

lineage arose by aneuploidy from a 2n=14 progenitor. 

Comparisons developed by juxtaposition of chromosome 

numbers with morphological characters and classification 

ranks indicate that subsections Pusilli, 

Oxyphylli, and Amplifolii may not represent entirely 

natural assemblages. The past use of chromosome 

numbers to demonstrate the primitiveness of floating 

leaves in the genus is challenged due to lack of 

correlation of these features when a larger number 

of species is considered. Chromosome numbers were 

found to correlate geographically with the hypothetically 

proposed birthplace of the genus. 

LEVIN, GEOFFREY 

A. Department of Biology, Ripon 

College, Ripon, WI 54971. - Phenetic and cladistic 

analysis of the foliar morphology of Phyllan- 

thoideae (EuRhorbiaceae). 

Systematists frequently regard leaf morphology as 

being of little taxonomic use, particularly at higher 

taxonomic levels, despite the recent advances made by 

paleobotanists in the classification of fossil 

leaves. In order to test the value of foliar 

characters in an extant group, a study of the 

Phyllanthoideae, the most primitive subfamily of the 

Euphorbiaceae, was undertaken. Leaves of 275 species 

representing 52 of the 58 genera were described using 

26 characters derived from Hickey's architectural 

terminology and 17 cuticular characters. Phenetic 

relationships between OTUs representing subgenera or 

undivided genera were initially analyzed using simi- 

larity graph clustering. Results using all OTUs were 

difficult to interpret, apparently due to extensive 

convergence between members of the subtribe Phyllan- 

thineae and other OTUs. Most of the Phyllanthineae 

exhibit a spec.ialized branc.hing pattern in whic.h


determinate lateral branches resemble compound 

leaves. Analysis using the 68 OTUs that lack this 

branching pattern produced clusters similar to those 

in classifications based on characters more widely 

recognized as being of systematic value. In a few 

cases, excessive convergence did cloud relationships, 

probably because of the use of overall similarity as 

the basis for classification. The results of a cla- 

distic analysis, in which the polarity of character 

states was determined using other subfamilies of the 

Euphorbiaceae and primitive genera in the Flacourtia- 

ceae as sister groups, even more closely resembled 

previous classifications. Obtaining such clear 

results using a group not known for having diagnostic 

leaves argues against the widely held idea that 

foliar morphology is of little systematic value. 

LOWREY, TIMOTHY K., and DANIEL J. CRAWFORD.* 

Department of Botany, University of Witwatersrand, 

Johannesburg, South Africa, and Department of 

Botany, The Ohio State University, Columbus, OH 

43210.--Allozyme divergence and evolution in 

Tetramolopium (Compositae:Astereae) of the 

Hawaiian Islands. 

Tetramolopium is a wholly insular genus of shrubby or 

suffrutescent perennial Compositae with a limited 

disjunct distribution in the Hawaiian Islands and New 

Guinea. In Hawaiian Tetramolopium there has been the 

evolution of distinctive morphological features. The 

taxa are, however, completely interfertile with fertile 

Fl, F2, and F3 hybrids being obtained, but no 

natural hybrids are known. Biogeographical evidence 

suggests that introduction of Tetramolopium into 

Hawaii may have resulted from a single recent introduction, 

indicating that morphological divergence and 

adaptive radiation occurred rapidly. Electrophoretic 

studies of allozyme variability support this hypothesis 

because there has been little divergence at gene 

loci coding for soluble enzymes. The mean genetic 

identity for pairwise comparisons of 19 populations 

from seven species is 0.95. This is comparable to 

values normally obtained for conspecific populations 

as contrasted with a mean genetic identity of 0.67 

for populations of congeneric species. The situation 

in Tetramolopium also contrasts sharply with other 

instances of high genetic identity between species 

where the taxa are very similar morphologically, yet 

reproductively isolated. Only a fewi genes may be 

responsible for the morphological and ecological 

differences between species of Hawaiian Tetramolopiurn. 

LUCKOW, MELISSA A. Biological Sciences Department, 

California Polytechnic State University, 

San Luis Obispo, CA 93407. - A morphometric and 

cytological study of Pectis longipes (Compositae). 

Pectis longipes is an herbaceous perennial occurring 

in southern Arizona, eastern New Mexico, and northern 

Mexico. Chromosome counts of n=12 and n=24 have been 

reported for the species. Field work also revealed 

that plants have one of two scents, designated as 

either "lemon" or "spicy". Chromosome counts from 

thirty populations show that the tetraploids are 

lemon-scented while the diploids are spicy-scented. 

A morphometric study using ordination and 

discriminant analysis was undertaken to determine if 

the races could be distinguished morphologically. 

Ni neteen vari abl es i ncl udi ng vegetati ve , fl oral, and 

pollen characteristics were measured for twenty 

individuals from each of six populations (three 

diploid, three tetraploid). Discriminant analysis 

performed best, correctly assigning 92% of the 

individuals. Of the incorrectly assigned individuals, 

all but one was assigned to another population of the 

same ploidy level. Canonical vectors separate popu- 

lations by ploidy level primarily on the basis of 

pollen size. 

MAGRATH, LAWRENCE K. Discipline of Biology, 

Department of Math/Science, University of Science 

and Arts of Oklahoma, Chickasha, OK 73018. 

- Orchidaceae native to Oklahoma: distribution 

and ecology. 

The family Orchidaceae is represented in Oklahoma by 

17 genera and 30 specific and subspecilic taxa. The 

taxa represented are: Aplectrum hyemale, Calopogon 

tuberosus var. tuberosus and var. simpsonii (?), 

Corallorhiza odontorhiza, C. wiqsteriana, Cypripedium 

calceolus var. pubescens, Epipactis gigantea, Goodyera 

pubescens, Habenaria repens, Hexalectris spicata, 

Isotria verticillata, Liparis lilifolia, 

Listera australis, Malaxis unifolia, Pogonia ophioglossoides, 

Platanthera ciliaris, P. clavellata, P. 

flava var. flava, P. lacera var. lacera, P. leucophaea, 

Spiranthes cernua (),S. lacera, S magnicamporum, 

S. odorata, S. ovalis, S. praecox, S. 

tuberosa, S. vernalis, Tipularia discolor, Triphora 

trianthophora. The largest number of taxa are concentrated 

in the SE corner of the state, with secondary 

concentrations in the NE and S central parts of 

the state. McCurtain county in the extreme SE corner 

has the largest number with 21 taxa, followed by 

Choctaw with 19, LeFlore with 16, Pushmataha with 14, 

Bryan with 11, Cherokee with 9, Delaware and Adair 

with 8, Ottawa, Haskell and Caddo with 7, Orchids 

have been reported from 50 of the 77 counties in the 

state. The only part of the state in which they have 

not been reported at the present time is the panhandle. 

Orchids occur in five major types of habitat 

in Oklahoma: 1) prairie and grassland (6 taxa), 2) 

woodland (15 taxa), 3) open sphagnum bogs (5 taxa), 

4) sphagnum bogs in wooded areas (4 taxa), and 5) 

open stream banks over limestone 

Mts. (l1 taxon). 

in the Arbuckle 

MAZE, JACK. Department of Botany, University 

of British Columbia, Vancouver, B. C. V6T 2B1, 

Canada. - A study of the factors affecting 

morphological differentiation in a population of 

Pinus ponderosa. 

Trees are amongst the most variable of organisms, 

the result, it would seem, of fusion between 

gametes from genetically different individuals. 

Genetically different individuals may result from 

selection, either past or present, causing 

population differentiation over small geographic 

areas or selecting for different individuals in 

different climatic regimes that prevail during 

different years. However, selection is not 

necessary to explain genetically different 

individuals. The evolutionary theory of Wiley and 

Brooks predicts an increase in variation as a 

consequence of natural laws pertaining to.increasing 

disorder. The effect of habitat differences, age, 

size of trees and past climate as evidenced by 

tree ring sitte-summaries on the pattern of 

variation was estimated by calculating the 

percentage of variation in principal components 

analysis axis scores for which each factor accounts. 

In all comparisons made, the greatest percentage

of variation (73-94%) was unaccounted for by any of 

the factors tested. While it may be argued that 

relevant selective factors were missed, it should 

be pointed out that such arguments can lead to the 

unacceptable stance of explaining away unpopular 

results by asserting that the important elements 

were not measured. A large percentage of variation 

that is apparently unaccounted for by selection is 

a prediction that would follow from the theory 

of Wiley and Brooks. 

McCALL, CLAIRE* and RICHARD B. PRIMACK, Biology 

Department, Boston University, Boston, MA 02215. 

- Does pollination 

field? 

level affect fruit set in the 

An unresolved question of plant reproductive biology 

is the relative importance of pollinator activity, 

resource limitation, and ovule abortion in regulating 

the final production of seeds. An experimental field 

study was undertaken to determine if inadequate 

pollination limited fruit set in 5 species of perennial 

forest herb. The experiments consisted of comparing 

the seed production of approximately 40 plants 

which were cross-pollinated by hand with 40 control 

plants. All plants were exposed to normal insect 

visits and grown in their natural environment. In 

Uvularia sessilifolia, Geranium maculatum, and 

Maianthemum canadensis, there was no difference in 

the fruit set of experimental and control plants. In 

Smilacina racemosa, fruit set was increased slightly 

(27% vs 20%). In Lysimachia quadrifolia, fruit set 

was increased dramatically by hand-pollinations in 

one population (61% vs 28%), but not in a second 

population (36% vs 33%). Hand-pollinations were 

effective at increasing fruit set on some days, but 

not others. In species in which fruit set is limited 

by pollinator activity, we still need to know if increased 

fruit set results in a corresponding decrease 

in some other fitness components such as subsequent 

survival or fruit production in later years. 

MCCORMICK, SUSAN P.* AND FRED GANDERS. Department 

of Botany, University of British Columbia, 

Vancouver, BC V6T 1W5. - Leaf flavonoids of 

Hawaiian Bidens. 

Leaf flavonoids were investigated for populations of 

nineteen Hawaiian Bidens species. Individual plants 

surveyed by two-dimensional TLC contained between 

ten and thirty flavonoid compounds. Individual 

compounds have been isolated and identified using 

co-chromatography, UV, proton NMR and mass spectrometry. 

pigments 

The flavonoids are primarily anthochlor 

including 4'-O-glycosides of butein, marein 

and lanceolin and 6-0-glycosides of sulphuretin, 

marimetin and leptosidin. Butein derivatives with 

methylation at the 3 or 4 position were present in 

some populations of B. torta. Kaempferol and 

quercetin monosides and biosides were present also 

in most populations. 

MCDOUGAL, KAREN. Department of Biology, University 

of North Carolina, 

- Geographic variability 

Chapel Hill, 

in flavonoid 

NC 27514. 

profiles of 

red oak, Quercus rubra L. 

Red oak, Quercus rubra L., is widely distributed 

throughout eastern North America. It is rich in 

flavonol glycosides, especially myricetin and 

quercetin pentosides. Two forms of red oak in the 


southern Appalachians differ in their foliar flavo- 

noid profiles and elevational distribution. Low 

elevation trees synthesize primarily quercetin glyco- 

sides; those at high elevations also produce myrice- 

tin glycosides. Trees with reduced levels of myri- 

cetin occur at mid elevations. Using HPLC we have 

obtained quantitative data on individuals from over 

the species range. These indicate that red oak 

chemotypes and the degree of population heterogeneity 

are correlated with latitude, longitude and eleva- 

tion. Myricetin-rich individuals occur primarily 

along the Appalachian range and at high latitudes. 

High elevation populations from the Ouchita Mountains 

of western Arkansas also display this pattern. These 

high latitude-high elevation populations exhibit a 

high degree of inter-population homogeneity, although 

there is some quantitative intra-population vari- 

ability. Quercetin-rich trees are found at low ele- 

vations on the eastern and southern range extremes. 

These populations are also very homogeneous chemi- 

cally. West of the Appalachians, populations are 

highly heterogeneous and contain both myricetin and 

quercetin producing individuals. The myricetin 

chemotypes in this area are somewhat reduced in over- 

all quantity, similar to trees at-mid elevations on 

the eastern slopes. From central Alabama and Georgia 

to central Ohio and Indiana, within-population vari- 

ability approaches that between populations, with 

the frequency of myricetins positively correlated 

with increasing latitude. 

McNEILL, JOHN* and STEVEN J. WOLF. Department of 

Biology, University of Ottawa, Ottawa, KlN 6N5, 

Canada. - Cytotaxonomic studies on Polygonum 

Sect. Polygonum in eastern Canada. 

Existing treatments of Polygonum Sect. Polygonum 

(including the P. aviculare complex) are extremely 

divergent in the number of species that they recog- 

nize and in the criteria that they use for species 

delimitation. The group is particularly well 

represented in Atlantic Canada, where the number of 

species maintained ranges from 8 in a review by 

Mertens and Raven (1965) to 21 in an account of 

chromosome numbers by Love and Love (1956). Chrom- 

osome counts from over 120 populations of the group 

in eastern Canada have revealed only tetraploid and 

hexaploid plants. It is postulated that the P. 

aviculare complex is represented, not only by intro- 

duced weedy plants referable to P. aviculare in the 

narrow sense (=P. monspeliense) (2n=60) and P. 

arenastrum (2n=40), but also by native tetraploid 

and hexaploid populations that are distinguishable 

but by different character combinations. These 

include not only P. buxiforme (2n=60) and P. boreale 

(2n=40) but also a number of undescribed variants. 

In addition to these members of the P. aviculare 

complex, five other species of the section can be 

distinguished in eastern Canada. Most of these more 

distinct species with shining nutlets appear to be 

native to North America, but the coastal P. raii 

(2n=40) is almost certainly introduced. Our data 

suggest that chromosome doubling in members of the 

section has occurred independently several times. 

MILLER, JOHN M*, CHARLES E. FELLOWS and KENTON L. 

CHAMBERS. Department of Biology, Sul Ross State 

University, Alpine TX 79832 and Department of Botany 

and Plant Pathology, Oregon State University, 

Corvallis, OR 97331 - Cytogeographic patterns and 

relationships of the Claytonia sibirica complex. 

Chromosome counts in dividing pollen mother cells 

frvom one hundred and forty populations of Claytonia


sibirica (s.l.) reveal a polyploid series based upon 

x=6. One rosette-forming diploid has rhomboid to 

deltoid mature basal leaves and occurs in the moun- 

tains of northern California, Oregon, Idaho, and Bri- 

tish Columbia. This species grows in cool, moist 

habitats. A second diploid, sp. nov. prov., possess- 

es linear mature basal and cauline leaves and vigor- 

ous rhizomes. Consistently mistaken for C. sibirica 

var. heterophylla (=Montia heterophylla), this taxon 

occurs near Mount Shasta southward at mid-elevations 

in palustrine habitats of the Sierra Nevada. In the 

Klamath Region diploids occur which are morphologi- 

cally intermediate between deltoid-leaved rosette- 

forming diploids and linear-leaved, rhizomatous di- 

ploids. These plants proliferate new rosettes from 

bulbils and stolons. Bulbiliferous tetraploids with 

narrow basal leaves occur in the Klamath Region. Non- 

bulbiliferous, deltoid-leaved tetraploids are the 

most widespread cytological race indigenous to wood- 

lands of Alnus rubra and Pseudotsuga menziesii except 

where replaced by hexaploid cytotypes on the northern 

California coast. Morphological variation and poly- 

ploidy in C. sibirica (s.l.) is parallel to other 

euploid complexes in Claytonia section Limmia, where 

unreduced gamete fusion coupled with limited natural 

hybridization among ancestral diploid species has led 

to higher chromosome levels. Inadequate knowledge of 

diploid taxa and the parallel variation exhibited by 

polyploid races has been the source of past taxonomic 

confusion in C. section Limmia. 

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Robinsonia correlates with the previously estab- 

lished subgenera and sections. The most likely 

hypothesis for the evolution of flavonoids within 

the genus is that the ancestor had only flavonols. 

In sect. Eleutherolepis a gain of flavanones, 

dihydroflavonols, and flavones occurred. Within 

this section R. masafuerae, the only species of the 

genus on the geologically younger island, Masafuera, 

has apparently lost apigenin during its evolution 

within the last 1 million years. 

PALMER, PATRICIA G. Department of Biology, 

Louisburg College, Louisburg, North Carolina 

27549. - An SEM analysis of epidermal features of 

African grasses and its paleoecological 

applications. 

Approximately 200 genera of tropical East and 

West African grasses are being analyzed with 

scanning electron microscopy to describe the 

epidermal features of the abaxial and adaxial 

leaf surfaces. A comparison of the major 

diagnostic features as viewed with light microscopy 

and SEM will be made to show advantages of SEM 

in many cases. SEM is particularly useful in 

identifying fossil grass leaves in African lake 

sediments. An analysis of the fossil grass 

cuticles in sediments from Lake Bosumtwi, Ghana, 

West Africa, shows an abundance of grass cuticles 

of the Pooideae subfamily in the late Pleistocene 

layers. This indicates a paleotemperature several 

degrees cooler than the present day. 

PARKER, WILLIAM H.* and JACK MAZE. School of 

Forestry, Lakehead University, Thunder Bay, Ont. 

P7B 5E1 and Department of Botany, University of 

British Columbia, Vancouver, B.C. V6T 2B1 

- Intraspecific variation in Abies lasiocarpa from 

British Columbia and Washington. 

Sixteen natural stands of Abies lasiocarpa (Hook.) 

Nutt. were sampled from British Columbia and Washing- 

ton to investigate patterns of intraspecific varia- 

tion in this species. Principal components analysis 

and canonical variates analysis were performed sepa- 

rately on seed-cone data, needle morphology data, and 

needle flavonoid data. Although significant differ- 

ences were detected between populations based on each 

of the three data sets, only variation in needle 

morphology followed a geoqraphic pattern. With the 

exception of the Vancouver Island population, three 

geographic groups were discerned based on their 

needle morphology: 1) populations from the coastal 

mountains of British Columbia, 2) those from the 

eastern interior of British Columbia, and 3) those 

from the Cascade Mountains of Washington. Although 

the Vancouver Island population was grouped with the 

interior British Columbia populations based on needle 

morphology, it was similar to the other coastal popu- 

lations based on flavonoid data. These inconsistent 

results among the three different types of taxonomic 

evidence suggest that the evolution of each of the 

three classes of characters has been partly inde- 

pendent from the other two and underscore the need to 

consider a variety of traits when drawing taxonomic 

conclusions in Abies. Our data offer little support 

for the recognition of infraspecif ic taxa within the 

study area, and are in contrast to Hunt and von 

Rudlof f' s results (Taxon 28: 297-305 ) which led them 

to conclude, based pr imar ily on terpeno id data, that 

coastal and inter ior populat ions of subalpine f ir 

were two separate species. 


PAVLICK, LEON E. Botany Division, 

British Columbia Provincial Iluseum, 

Victoria, B.C., Canada, V8V 1X4. - 

Studies on the Festuca ovina complex in 

the Canadian Cordillera. The Festuca 

ovina complex in the Canadian Cordillera 

was studied. Based on morphology and 

anatomy seven taxa are characterized and 

their taxonomy discussed. The 

proliferous material of Zie ovina 

complex in the Cordiliera is different 

f rom F. vivipara (L.) Sm. and a new 

name, F. krajiinae, is proposed. A nex 

variety from wesLern British Columbia, 

F. saximontania Rydb. var. robertsiaua, 

is described. The other taxa treated 

are: Festuca saximontana Rydb. var. 

saximontana; F. saximontana var 

purpusiana (St.-Yves) Frederiksen & 

Pavlick; F. brachPnyllia Schult. & 

Schult.; F. baffiliensis Polun.; and F. 

minutiflora Rydb., a species rarely 

collected in Canada. Distributionis are 

given. 

PERINO, CHARLES H.* Illinois Department of 

Transportation, 2300 S. Dirksen Parkway, 

Springfield, IL 62764 and JAMES R. ESTES 

Department of Botany, University of Oklahoma, 

Norman, OK 73069. 

- Systematics of Chactopappa series Effusae 

(Compositae). 

A morphological examination of the Chaetopappa 

series Effusae(C. effusa, C. keerlioides, and 

C. parryi was done. Chaetopappa effusa is recognized 

as a distinct genus on the basis of seven 

morphological characters: disk style branches, 

phyllaries, pappus, corolla trichomes, anther 

appendages, leaf structure, and chromosome number. 

The new genus, Loshinnsia, gen. n., has one species, 

L. effusa (Gray) Perino & Estes comb. nov., 

and it is restricted to the eastern edge of the 

Edwards Plateau of central Texas. 

PHILLIPS, MARC N. and ROBERT R. KOWAL.* 


Madison, WI 53706. - Systematics of Saxifraga 

pensylvanica and a putative segregate species, 

S. forbesii (Saxifragaceae). 

George W. Burns in 1942 recognized the tetraploid 

(n=28) species, Saxifraga forbesii Vasey, occur- 

ring in the Midwest mostly on sandstone cliffs in 

unglaciated areas. It was split from S. pensyl- 

vanica L. of northeastern North America, within 

which Burns recognized three subspecies: tetra- 

ploid, hexaploid, and octoploid (n=28, 42, 56). 

To re-evaluate Burns' work, samples from seven 

populations from Missouri (1) and Wisconsin (6), 

possibly representing S. forbesii (based on habi- 

tat, range, and Burns' annotations of specimens), 

and twelve populations from Wisconsin, represent- 

ing ordinary S. pensylvanica, were grown in a 

transplant garden. The resultant data on 30 

morphological characters, petal color, flowering 

time, stomates and pollen were analyzed with 

appropriate statistical techniques including canon- 

ical analysis. Although abundant differences 

occurred among local populations, none existed


between S. pensylvanica and populations supposed- 

ly representing S. forbesii. Hybridizations 

showed no genetic isolation between the two. 

Chromosome counts from the garden were uniformly 

2n=ca. 8x, even though mostly tetraploids were 

expected based on Burns' annotations. A count 

from the type population of S. forbesii gave 2n= 

ca. lOx, and one from S. pensylvanica from North 

Carolina, where Burns predicted tetraploids, gave 

2n=ca. 11-14x. Thus, no morphological or cyto- 

logical evidence exists for recognizing S. forbesii, 

and the polyploid complex within S. pensylvanica 

is both more diverse and more morphologically 

cryptic than Burns had supposed. 

PILATOWSKI, RONALD E. Department of Botany, 

The Ohio State University, Columbus, OH. 43210. 

- A phenetic analysis of Liatris Series 

Graminifoliae (Compositae; Eupatorieae). 

Liatris Schreber is a large genus of perennial herbs 

of eastern North America. Series Graminifoliae consists 

of five species distributed along the Coastal 

Plain, Piedmont, and Mountain provinces of the 

American Southeast. A phenetic study using the 

NT-SYS package was done on this group, using a 

total of 46 characters on a total of 126 OTU's representing 

the five recognized species in the Series: 

L. gracilis, L. graminifolia, L. helleri, L. regimontis, 

and L. turgida. Results of this phenetic 

study indicate the following: (1) L. helleri, an 

Appalachian endemic which has been suggested to be 

an ecotype of L. graminifolia, was found to comprise 

a distinct group in the analysis; (2) The somewhat 

morphologically similar L. turgida, also an Appalachian 

endemic, was found to be distinctive; (3) 

Overlap between two species found on the Coastal 

Plain of North and South Carolina, L. graminifolia 

and L. regimontis, suggests hybridization, an observation 

made by other investigators of the genus; 

(4) Plants collected from the unique steephead habitats 

in the vicinity of the Apalachicola River in 

Liberty County, FL., which have traditionally been 

regarded as L. gracilis, segregate from the main body 

of this species in factor analysis; and (5) Two 

major groups can be distinguished in the analysis 

which correspond to flavonoid differences found in 

the Series. 

POHL, RICHARD W. Department of Botany, Iowa State 

University, Ames, Iowa 50011. -Current blooming 

status of the bamboo flora of Costa Rica. 

I have observed native and cultivated bamboo stands 

for 17 years. Species currently blooming are (native): 

Chusquea longifolia, C. meyeriana, C. "talamancae 

", Otatea acuminata, RhTlpidocladum baFtlettii, 

and Swallenochloa subtessellata; (cultivated): Bambusa 

vulgaris, B. longispiculata, Phyllostachys aurea: 

The following have been seen in bloom since 1965,Tbut 

are currently only vegetative: Aulonemia patriae, 

Arthrostylidium venezuelae, Bambusa paniculata, 

Chusquea "cariblanco", C. coronalis , C. scabra, C. 

tonduzii. C. virgata, ETytrostachys cTavigera, 

Rhipidocladum maxonii, R. pittieri, R. racemiflorum, 

Swallenochloa longiligulata, S. vulcanalis. Bambusa 

arundinacea, a cultivated Asiatic species, was in 

widespread bloom in the 1970's, but is now vegetative. 

The fol lowing native species have never been observed 

in bloom: Arthrostylidium harmonicum, A. pubescens, 

Chu sq uea "h isp id is s ima", Chu s ua tarra zu "w a si ve 

gregarious blooms of Chusquea longifolia occurred on 

Volcan Irazu and of Rhipidocladum bartlettii near the 

Rio Pacuare. 

POLLARD, A. JOSEPH. Department of Botany and 

Microbiology, Oklahoma State University, 

Stillwater, OK 74078. 

- Biosystematic studies of gene flow and natural 

selection in Urtica dioica (stin in nettle). 

An extreme variant of Urtica dioica, characterized 

by paucity of stinging hairs, tall unbranched growth 

form, long narrow leaves, and late flowering, occurs 

in large numbers at Wicken Fen, Cambridgeshire, 

England. Experimental cultivation of plants 

collected along a transect crossing the boundaries 

of the variant population has revealed that: 

(1) Significant gene flow into the population occurs 

by both seed and pollen transport. 

(2) Pollen flow also has significant effects within 

populations, acting to smooth out variation expressed 

in the adult generation. 

(3) Patterns of variability do not indicate that 

natural selection is acting to limit the range of 

variability contained in the seed population. 

(4) It would be erroneous to cQnclude from (3) that 

selection is not occurring, since, for a long-lived 

perennial like U, dioica patterns of variability 

may be more related to historical factors than to 

current selectional regimes. 

PRIDGEON, ALEC M.* and WILLIAM LOUIS STERN. 

Department of Botany, University of Florida, 

Gainesville, FL 32611. - Osmophores in selected 

Orchidaceae: location and ultrastructure. 

Osmophores are floral tissues specialized for synthe- 

sis and secretion of fracrrances serving as pollinator 

attractants. Location of osmophores on flowers of 

Orchidaceae may or may not have an assignable role in 

the pollination process. In members of the fly- 

pollinated subtribes Pleurothallidinae and Bulbo- 

phyllinae, osmophores are positioned at sepal apices, 

petal apices, or both, and probably function only in 

attraction of pollinators over long distances. Os- 

mophores of many euglossine-pollinated orchids, how- 

ever, are usually situated on the adaxial surface of 

the labellum over or under the column, so that male 

bees come into contact with pollinia or the stigmatic 

surface. At the ultrastructural level in osmophores 

of the myophilous genus Restrepia, a strongly osmio- 

philic and lipidic exudate is synthesized in papil- 

lose epidermal cells of the dorsal sepal and petals. 

As the exudate is amassed, the cuticle ruptures to 

form numerous pores that extend from the cell wall. 

Mitochondria and amyloplasts are especially abundant 

at anthesis. Lipid droplets, perhaps counterparts of 

the terpenoid fragrances produced, also appear i-n the 

cytoplasm and vacuome oL epidermal cells at anthesis. 

Data drawn from these and other lines of inquiry 

should assist in indicating relationships below the 

subtribal level in Orchidaceae because the evolu- 

tionary history of this family is, by and large, the 

history of adaptive change and refinement in floral 

morphology and fragrances. 

RABELER, RICHARD K. Beal-Darlington Herbarium & 

Lyman Briggs School, Michigan State University, 

East Lansing, MI 48824-1312. - Petrorhagia 

(Caryophyllaceae) of North America. 

As an outgrowth of the discovery of Petrorhagia 

prolifera (L.) P. Ball & Heyw. in Michigan, the 

genus Petrorhagia (Ser. in DC.) Link, revised by 

Ball & Heywood in 1964, is applied to North American 

material. Four species, all introduced from Europe, 

are considered based on field study and an extensive 

herbarium survey. The history of introduction 

(where known), distribution, and current status of

each species will be presented. Petal vein color 

is described as an additional character that can be 

used in distinguishing the three species of the 

P. prolifera complex occurring in North America. 

REYNOLDS, HOWARD C. Dept. of Biology, 

Ft. Hays State University, Hays, KS 67601 

- Botanizing Papua New Guinea 

The author had the opportunity to study and 

photograph the flora and fauna of PNG as a member 

of the Pre-Congress Botanical Tour to that country 

in connection with the XIIIth International 

Botanical Congress held in Sydney, Australia. The 

natural history highlights were observed between 

Aug. 8-19, 1981. The author had previously 

observed the natural history of PNG as a member of 

the Medical Dept. of the U.S. Army during WW II 

about 38 years prior to his second visit. Since 

part of the tour was made by motor vehicle, a good 

opportunity was afforded to observe the Nothofagus 

forest in the area around Mt. Hagen and the 

Castano sis forest in the vicinity of Goroka, both 

in the ighlands. Good examples of lowland rain 

forest were observed in the vicinity of Madang and 

Lae along the east coast. "Manmade" grasslands 

were especially extensive as observed in the Ramu 

and Markham river valleys with members of the 

Andropogoneae (Bluestem tribe) as dominants. Port 

Moresby with its pronounced dry season and Savannah 

type vegetation was in marked contrast to the 

tropical rain forest which makes up about 75% of 

the vegetation of PNG. 

REZNICEK, ANTON A.*, and PAUL M. CATLING, Univer- 

sity of Michigan Herbarium, North University Bldg., 

Ann Arbor, Michigan 48109 and Biosystematics Re- 

search Institute, Agriculture Canada, Wm. Saunders 

Bldg., C.E.F., Ottawa, Ontario K1A 0C6. 

- The Identity of Carex caesariensis and C. sub- 

impressa. 

Carex caesariensis, known only from southern New 

Jersey and C. subimpressa occurring more widely in 

the middle west, are two puzzling species of Carex 

sect. Paludosae. Both have been suspected of being 

hybrids. Carex caesariensis has usually not been 

considered a good species. A hybrid parentage of C. 

trichocarpa and C. walteriana has been proposed. Be- 

cause of a unique combination of characters, includ- 

ing elongate sterile culms, reddened sheath apices 

and long beak teeth, there is little doubt that C. 

trichocarpa is one parent. Although we were unable 

to rediscover C. caesariensis in the field, we pro- 

pose that the other parent is actually C. lanuginosan 

Statistical analysis using a number of characters 

supports this, as well as the ecological character- 

istics of the type locality. Carex subimpressa was 

originally described as a hybrid of C. hyalinolepis 

and C. lanuginosa. Subsequent authors often have 

been inclined to recognize it as a good species, pre- 

sumably because of its wide range. Also, specimens 

referable to C. subimpressa have been collected be- 

yond the range of C. hyalinolepis. However, morpho- 

logical and anatomical characteristics support its 

hybrid origin, as do field studies of natural popula- 

tions. Collections from beyond the range of C. hya- 

linolepis are shown to be referable to hybrids of 

different parentage or abnormal forms of other 

species. 


RICHARDSON, P. MICK. New York Botanical Garden, 

Bronx, New York 10458. - Problems of congruence 

of chemical and morphological data. 

The current taxonomic treatment of Lasthenia recognizes 

16 species in 6 sections (Ornduff, 1966). A 

thorough analysis of the flavonoids in the genus has 

been interpreted as confirming the current sectional 

boundaries (Bohm, Saleh and Ornduff, 1974). Character 

compatibility analysis of the flavonoid data appeared 

to also support the prevailing taxonomy of the genus 

(Estabrook, 1980). However, when the character state 

polarities of Bohm et al.(1974) were used in a cladistic 

analysis the results disagreed with the earlier 

interpretations. The protein electrophoresis data of 

Altosaar, Bohm and Ornduff (1974) also disagreed with 

the current taxonomy of the genus. If there has been 

correct interpretation of all the data then congruence 

among them would be expected. Reinterpretation 

of all the available data is necessary in order to 

understand this case of incongruence. 

ROBBINS, LAURIE R. Department of Biological 

Sciences, Texas Tech University, Lubbock, TX 79409. 

- Systematics of the fleshy-fruited Yuccas in the 

Chihuahuan Desert. 

Relationships among eight species of fleshy-fruited 

Yuccas in the Chihuahuan Desert were inviestigated. 

Morphometric, flavonoid, and electrophoretic tech- 

niques were employed in an effort to elucidate 

relationships within several species complexes. 

Historically, because of large plant size and the 

inaccessibility of several of the species, sample 

sizes have been small. The true degree of intra- 

and interpopulational variation, therefore, has 

never been established. In this study, the analysis 

of large samples revealed considerably more morpho- 

logical variability than previously reported. This 

variability blurs taxonomic boundaries within 

several of the species complexes. Additionally, 

flavonoid and electrophoretic data further indicate a 

more conservative treatment of the group than 

produced by previous workers. 

ROBERTS, MARVIN L. and ROBERT R. HAYNES*. 

Department of Biology, University of Alabama, 

University, AL 35486. - Chemosystematics of the 

genus Najas (Najadaceae). 

The infrageneric classification of Najas has been 

based on leaf sheath morphology and the occurrence of 

a floral envelope. Recent evidence from seed coat 

morphology suggest other divisions within the genus. 

An examination of flavonoid pigments in North 

American taxa indicates considerable diversity in 

flavonoid composition. Najas marina, in subgenus 

Najas, produces flavone-7-0-glycosides. Certain 

taxa of subgenus Caulinia produce the same compounds 

and also 5-0-substituted flavones and 3-0- and 7-0- 

substituted flavonols. Najas flexilis and N. 

guadalupensis stand apart from these taxa in lacking 

7-glycosylated flavones but producing 5-deoxy flavones 

and flavonols. Geographic and/or seasonal variation 

in flavonoid profiles are apparent in several species. 

The flavonoid data largely support an infrageneric 

classification based on seed coat morphology.


ROBERTSON, KENNETH R. Illinois Natural History 

Survey, Champaign, IL 63120. - oo identif 

bee 

Species of the genus Amaranthus (including subgenus 

Acnida) 

familiar 

are difficult to identify for someone not 

with the group, and many specimens in 

herbaria are misidentified, often grossly so. In 

this paper, the important 

istics used to distinguish 

morphological characterspecies 

of Amaranthus 

will be discussed and illustrated with photographs. 

Within a given geographical area, species are rarely 

distinguishable vegetatively. Flowers are 

essential, and mature fruits are also frequently 

necessary; both flowers and fruits are usually found 

on plants collected from late summer until the end 

of the growing season. The flowers of Amaranthus 

are imperfect, and each species is consistently 

either monoecious or dioecious. This is the first 

character to determine when identifying an Amaranth. 

Other characters used to distinguish species are: 

inflorescence 

or axillary 

type and position (terminal 

clusters); size and shape of 

panicles 

inflorescence bracts; number, size, and shape of 

tepals of carpellate flowers; number of tepals and 

stamens of staminate flowers; size, texture, 

and dehiscence of utricles; and color, size, 

surface texture of seeds. 

shape, 

and 

SCHLESSMAN, MARK A. Department of Biology, 

Vassar College, Poughkeepsie, NY 12601 - Floral 

biology 

York. 

of American ginseng in southeastern New 

American ginseng, Panax quinquefolium, is threatened 

by commercial collecting. Because the floral 

biology of P. quinquefolium is of interest to 

ginseng growers, conservationists and botanists; I 

initiated a study of floral morphology, pollination 

and mating systems 

New York. 

of a population in southeastern 

In 1982 1 observed 3 types of flowers: perfect 

with 2 styles and 2 developed ovules; perfect with 

one style and 1 developed ovule; and functionally 

staminate with 1 style and no developed ovules. 

Perfect flowers were homogamous, with styles 

recurved and stigmas receptive at anthesis. 

Emasculation and bagging experiments and handpollinations 

pollination 

in the field showed that: 1) 

is required for seed set; 2) P. 

quinquefolium is self-compatible; and 3) selfing may 

occur via autogamy. The predominant floral visitors 

were syrphid flies (Mesograpta boscii, Melanstoma 

mellinum), halictid bees (Dialictus sp.) and ants 

(Prenolepsis imparis, Myrmica brevinodis). The mean 

percentage of flowers bearing fruits in a sample of 

64 naturally pollinated individuals was 29 + 23. 

Reproductive status was correlated with the 

morphological class, and hence age, of individuals. 

All 1-pronged plants were vegetative, and only 46% 

of the 2-pronged plants flowered. In contrast 96% 

of 3-pronged plants and all of the 4-pronged plants 

bore flowers. The mean percentages of 1-styled 

flowers were 93 for 2-pronged, 60 for 3-pronged, and 

11 for 4-pronged plants. The low level of fruit 

production and abundance of 1-styled flowers in this 

population 

limited. 

suggest that reproduction is resource- 

SCHLICHTING, CARL D. Department of 

Botany, University of Texas, 

78712. - Evolution of 

alas tic ity in Phlox 

Austin, TX 

phenotypic 

Drummond ii . 

Phenotypic plasticity is the ability of an 

individual plant to respond to differing 

environmental conditions. The evolution 

of the plasticity of a variety of 

characters (e.g. dry weight, flower size, 

reproductive effort) was examined within 

Phlox drummondii. A number of cultivated 

varieties have been derived from wild P. 

Drummondii, and in some areas of Texas 

these cultivars have 'escaped' back into 

the wild. Comparison of the plasticity of 

wild, cultivated and feral populations 

shows varying amounts of evolution of 

plasticity for different characters. For 

example, the pattern and amount of 

plasticity of flowering time are quite 

similar for wild P. drummondii and the 

cultivar Chamois Rose, whereas an escaped 

cultivated population from Jewett, Texas 

has much less plasticity and a different 

pattern of response to environments. The 

relative amounts of evolution of the 

plasticity of various characters may be 

related to the effects of drift or 

natural/artificial selection, depending on 

the adaptive nature of the plasticity of 

that particular character. 

SCHNEIDER, EDWARD L. Department of Biology, 

Southwest Texas State University, San Marcos, TX 

78666. - Floral Biology of Ondinea purpurea den 

Hartog. 

The floral biology of Ondinea purpurea, consisting 

of an apetalous subspecies and a newly discovered 

petaloid subspecies, has been investigated. 

Anthesis occurs over a 3-day period. First-day 

flowers are protogynous and characterized by color- 

ful reflexed perianth and staminal parts. The 

pollen-receptive stigmas of first-day flowers 

secrete a fluid that fills the small stigmatic cup. 

As potential pollinators are attracted and attempt 

to land on the distally exposed gynoecium, they con- 

tact the stigmatic fluid which loosens pollen from 

the insect's body and pollination is achieved. 

Second- and third-day flowers are functionally 

staminate. On the basis of comparative reproductive 

anatomy and pollination syndromes the placement of 

Ondinea in the Nymphaeaceae sensu stricto is 

supported. 

SCHWARZ, 

A.G.* AND R.E. REDMANN. Department of 

Crop Science and Plant Ecology, University of 

Saskatchewan, Saskatoon, Sask. S7N OWO. 

- Phenology of northern halophytic C3 and C4 

grasses. 

In Saskatchewan, C3 and C4 species coexist in saline 

habitats. The phenology of Agropyron trachycaulum 

(C3), Spartina gracilis (C4), Puccinellia nuttaliana 

(C3), and Distichlis stricta (C4) was studied from 

May to September. Observations of growth stage, 

height, number of leaves, and number of tillers were 

made on twenty individuals of each population. En- 

vironmental measurements included air and soil temp- 

eratures, rainfall, soil water content, and salinity. 

Spring regrowth began earlier in C3 plants than in 

C4 plants. Species from the strongly saline vegeta- 

tion zone (P. nuttalliana and D. stricta) began 

flowering earlier than species from the moderately 

saline vegetation zone (A. trachycaulum and S. 

gracilis) . Within both zones, f lowering of G3 and 

C4 species was essentially simultaneous. New growth 

occurred in autumn among the G3 plants. Distinct 

temporal separation of the C3 and C4 grasses 

probably is impossible, because of the relatively 

short growing season.

SEAMAN, FRED C. Harding Laboratories, New York 

Botanical Garden, Bronx, NY 10458. - Terpenoid 

characters and the systematics of Montanoa 

(As teraceae). 

Sesquiterpene lactone and diterpene chemistries of 

the genus Montanoa (Heliantheae) are being surveyed. 

Seventeen of the 30 taxa have been investigated,and 

novel compounds have been identified from each taxon. 

These novel compounds provide the basis for deriving 

skeletal and substitutional characters which are 

important in the study of Montanoa systematics. 

Examples of important characters are novel germacra- 

12,66-olides (skeletal) and C-5 hydroxylation (sub- 

stitutional). The distribution of chemical characters 

is being compared to a morphologically based 

cladistic analysis and taxonomic revision by V.A. 

Funk. Preliminary results indicate that there are 

areas of conflict between the distribution of novel 

chemical characters and the subgeneric and sectional 

boundaries proposed by Funk. However, the chemical 

characters support her treatment of the M. tomentosa 

and M. leucantha complexes. A hypothetical biosyn- 

thetic (biogenetic) rationale for these novel 

characters is presented. 

SEAVEY, STEVEN R. Department of Biology, Lewis 

and Clark College, Portland, OR 97219. - A novel 

self-incompatibility in Epilobium obcordatum 

(Onagraceae),. 

Seed set in greenhouse-grown individuals of Epi- 

lobium obcordatum is 3 to 13 times greater in out- 

crossed flowers than it is in self ed flowers. Self 

pollen germinates and grows normally through the 

style to the ovary, self fertilization occurs and 

early embryonic development is apparently normal. 

Sometime between day 3 and day 9 following pollina- 

tion, self ed embryos frequently cease developing 

and remain in an undifferentiated, globular state; 

the endosperm of these embryo sacs is not as abun- 

dant as in normally developing embryo sacs. Seed 

set following delayed and mixed pollinations demon- 

strates that self pollen removes ovules from the 

pool of potential seeds, even though all fruits 

contain a large proportion of unfertilized ovules. 

SHULTZ, LEILA M. Intermountain Herbarium, 

Department of Biology, Utah State University, 

Logan, UT 84322. - Origin and distribution of 

Artemisia rothrockii (Asteraceae, Anthemideae). 

Artemisia rothrockii was described by Asa Gray in 

1876 from populations near Olancha Peak in the 

southern Sierra Nevada mountains of California. The 

name has since been misapplied to more widespread 

populations of putative hybrid origin. Similarities 

between the central Sierran and Rocky Mountain 

populations of Artemisia have given rise to reports 

of A. rothrockii throughout the Rocky Mountain Region. 

Flavonoid profiles of the taxa involved are discussed 

with an estimation of their utility in determining 

interspecif ic relationships. Morphological and 

chromosomal evidence, as well as unique features of 

leaf anatomy, are used to support the recognition of 

A. rothrockii as a California endemic. Populations 

normally referred to as A. rothrockii appear to be 

hybrids of various subspecies of A. tridentata and 

A. cana. 


SIMMONS, KAREN S. Department of Botany, 

Washington State University, Pullman, WA 99164- 

4230. - Androdioecism and sex ratios in Lomatium 

Raf. (Umbelliferae). 

Species of Lomatium exhibit unique and interesting 

breeding systems. This primarily entomophilous 

genus of 73 western North American species ranges 

from andromonoecism to androdioecism. This results 

in very skewed male-biased individual and population 

sex ratios. Eight field sites of Lomatium species 

have been monitored for sex ratios for up to three 

years. Shifts in population sex ratios and individual 

gender expression have both been documented in 

L. triternatum and L. nudicaule. Shifts have been 

observed in both directions, towards increased 

maleness and decreased maleness, but sex ratios were 

always more than 50% male and ranged as high as 

76% male. A high percent of aborted ovules was also 

observed in most populations, resulting in even more 

male-biased functional sex ratios: Sexual selection 

for increased male competition may be an important 

selective force in the evolution of this system. 

SMITH, EDWIN B. Department of Botany and Micro- 

biology, University of Arkansas, Fayetteville, AR 

72701. - Biosystematic studies of the Californian 

Coreopsis (sections Tuckermannia, Pugiopappus 

and Euleptosyne). 

Biosystematic studies of the eight species of 

Californian Coreopsis were attempted. The group is 

refractory to the biosystematic approach. Arti- 

ficial interspecific hybridizations were attempted 

in all combinations but produced only one successful 

combination (C. maritima X C. gigantea). All eight 

species are n = 12. The meiotic chromosomes of the 

perennials (section Tuckermannia) are much larger 

and easily distinguishable from those of the annuals 

(sections Pugiopappus and Euleptosyne), but the 

chromosomes of each subgroup (annuals or perennials) 

are not easily distinguishable inter se. The three 

sections are well-differentiated morphologically and 

deserve sectional status. On the basis of several 

trends in morphology presumably indicative of 

phylogeny, section Tuckermannia is most primitive, 

Pugiopappus intermediate, and Euleptosyne the most 

advanced. Probable phyletic lines within the 

sections appear rather clearcut in sections Tucker- 

mannia (from C. gigantea to C. maritima) and 

Pugiopappus (from C. calliopsidea to C. bigelovii to 

C. hamiltonii), but less obvious in section Eulepto- 

syne. The most likely phylogeny in the latter 

section appears to be C. stillmanii to C. douglasii 

to C. californica, even though this involves a 

reversal in achene characters within the section. 

This entire group in California was probably derived 

from the primitive Mexican/South American section 

Pseudoagarista. 

SODERSTROM, THOMAS R. and FERNANDO 0. ZULOAGA * 

Department of Botany, Smithsonian Institution, 

Washington, D.C. 20560 and Instituto de Botanica 

Darwinion, San Isidro, Republica Argentina. 

- Systematic value of the sculpturing and 

epidermal patterns of the anthecium of Olyra 

(Poaceae: Bambusoideae). 

The bambusoid genus, Olyra, comprises some twenty 

species in tropical America, distributed from


southern Mexico to northern Argentina. The species 

of this monoecious grass have been distinguished on 

the basis of the type of female and male spikelets, 

their arrangement within the inflorescence, and 

disposition of the inflorescence within the plant. 

As in other members of the Olyreae, the anthecia of 

Olyra are hard at maturity and resemble those 

characteristically found in the unrelated tribe, 

Paniceae. 

SEM studies of the anthecia of all species of Olyra 

reveal marked differences among them, including 

various types of sculpturing such as round, ellipti- 

cal or hexagonal pits, narrow or broad excavations, 

and diverse epidermal patterns. The latter vary from 

relatively smooth to rugose surfaces with hooks and 

the presence of several kinds of hairs, including 

round to flattened macrohairs and short, globose 

bicellular microhairs, unusual in the subfamily. 

The anthecial patterns, as revealed by SEM studies, 

support the previous arrangement of species in the 

genus based on exomorphological characters. 

SOLTIS, DOUGLAS E. Department of Biology, Univer- 

sity of North Carolina, Greensboro, NC 27412. - 

Allozymic variability in four eastern U. S. spe- 

cies of Heuchera (Saxif ragaceae). 

Heuchera americana, H. parviflora, H. pubescens, and 

H. villosa are diploid (2n = 14) herbaceous perenni- 

als occurring in the eastern U.S. Individuals from 

populations representing these four species were in- 

vestigated utilizing starch gel electrophoresis. Al- 

lozymic data were obtained for 14 enzymes apparently 

encoded by 16 loci. Although low, values of P and H 

for these species of Heuchera are higher than those 

obtained for species of the related genus Sullivantia 

(Soltis, 1982). The greater genetic variability of 

Heuchera species may be attributable to breeding sys- 

tem; the investigated species of Heuchera are obli- 

gately outcrossing, whereas species of Sullivantia 

predominantly self. Allozymic data also have taxo- 

nomic implications. Rosendahl et al. (1936) assigned 

H. pubescens to section Heruchea and placed the re- 

maining three species in separate subsections of sec- 

tion Americanae. Based on crossability data, Wells 

(1979) suggested taxonomic changes at the sectional 

and subsectional level. Electrophoretic data indi- 

cate a high degree of similarity among the species 

investigated, but clearly define two groups. Heu- 

chera villosa and H. parviflora form one group, 

whereas H. americana and H. pubescens are allozymic- 

ally more similar to each other. The relationships 

suggested by allozymic data are not in agreement with 

the traditional treatment of Rosendahl et al., but do 

support the taxonomic changes suggested by Wells. 

SOLTIS, DOUGLAS E.* and BRUCE A. BOHM. Department 

of Biology, University of North Carolina, 

Greensboro, NC 27412, Botany Department, Univer- 

sity of British Columbia, Vancouver, B.C., V6T 1W5 

Canada. - Flavonoid chemistry and karyology of the 

disjunct species of Tiarella (Saxifragaceae). 

Tiarella is a genus of herbaceous perennials, and is 

generally considered to comprise three species: T. 

cordifolia, T. trifoliata, and T. polyphylla. These 

species are distributed in eastern North America, 

western North America, and eastern Asia, respective- 

ly. Numerous other genera Of vascular plants simi- 

larly display this well-known f loristic dis junction 

(Wood, 1972). Available evidence indicates that this 

disjunction arose during the late Miocene (10-12 mil- 

lion years B. P . ). Prior to the late Miocene, the 

northern latitudes were essentially encircled by a 

Mixed Mesophytic Forest community. Despite informa- 

tion regarding the events that disrupted this once- 

continuous community, few studies appear to have 

compared in a biosystematic fashion related species 

displaying this disjunction. We therefore initiated 

a flavonoid chemical and karyotypic comparison of the 

species of Tiarella to determine the extent of dif- 

ferentiation among these apparently long isolated 

species. Chromosome studies have shown all species 

of Tiarella to be characterized by the same chromo- 

some number (2n = 14), and essentially identical 

karyotypes. Although chromosomal evolution in the 

genus appears to be conservative, flavonoid differ- 

entiation has occurred among the species. Each 

species of Tiarella is chemically distinct. Appar- 

ently significant differences in monoglycosides 

exist between the North American species, T. cordi- 

folia and T. trifoliata. Triglycosides appear to be 

absent from T. polyphylla, whereas they are present 

in the North American species. Furthermore, T. poly- 

phylla displays the simplest array of flavonoids. 

SOUKUP, VICTOR G. Herbarium, University of 

Cincinnati, Cincinnati, OH 45221 & Hormel 

Institute, Austin, MN 55912.- Leaf Hydrocarbons 

of Trillium (Liliaceae). 

The approximately 60 species of Trillium are native 

to eastern and western North America and eastern Asia 

to the Himalayas. Species vary from about 6 to 55 cm 

in height with the areas of individual leaves (bracts) 

ranging from about 4 to 300 cm2. Only one bract was 

collected from each plant but with small species up 

to 25 bracts were collected from individual plants in 

a colony to make up a specimen. Total leaf hydrocarbons 

were determined on representative specimens 

from various populations of each species. Bracts 

were collected in early anthesis and comminuted in a 

blender in chloroform/methanol solvent. Hydrocarbons 

were obtained from the crude extract by TLC on silica 

and analytically separated by GLC on an SE-30 25 meter 

glass capillary column. Normal aliphatic hydrocarbons 

from C to C were found with C ,C , and C 

15 34 25 27' 2 

predominating. 

C15tC23 C24'C25'C28' 30 31 .C4 

were also important in North American species whil e 

C18 ,Cg,C 

in Asiatic 

2,C22 C24C6 

, and C28 were also 

species. bimilarities between 

important 

species run 

from a high of 0.955 to a low of 0.345. Results 

generally support affinities suggested on morphological 

basis but there are some notable exceptions, 

e.g. the T. pusillumn varieties. 

SPENCER, KEVIN C.* and DAVID S. SEIGLER. 

Department of Botany, University of Illinois, 

Urbana, IL 61801. - Systematics of Adenia 

(Passifloraceae): Numerical Analysis and Chemistry. 

In an analysis of the distribution of cyanogenic 

glycosides in the Violales we discovered that the 

possession of certain substitutional types of 

cyclopentenoid cyanogens was indicative of taxonomic 

relationships at the familial level. In order to 

test the predictive utility of cyclopentenoids at 

the generic level and below, we combined a chemical 

study of the genus Adenia with a numerical analysis 

of its morphological characters. Cladistic and 

phenetic analyses of up to 80 characters in the 92 

described species in the genus using several in- 

and out-groups yie lded a consistent pattern of 

species association . Application of data on the 

distribution of the different types and combinations 

of cyclopentenoid cyanogens within the genus

provided a basis for constructing a reasonable 

cladogram of Adenia. The success we have had with 

reconstruction of a classification in this genus 

encouraged us to model a similar approach for use 

in the analysis of the systematics of the large 

genus Passiflora and the family Flacourtiaceae. 

SPOONER, DAVID M. Department of Botany, The 

Ohio State University, Columbus, OH 43210. 

- Morphological variation and distribution of 

Gratiola viscidula (Scrophulariaceae). 

Gratiola viscidula Pennell is currently documented 

from 86 counties in the Piedmont and adjacent 

Atlantic Coastal Plain and southern section of the 

Blue Ridge Province. In addition, disjunct popula- 

tions are located farther west, to the Ozark Plateau 

in southeastern Missouri and the Allegheny Plateau 

in southeastern Ohio and adjacent Kentucky and West 

Virginia. The species was separated into two sub- 

species by Pennell in 1935: G. viscidula subsp. 

viscidula and G. viscidula subsp. shortii Durand ex 

Pennell. The latter subspecies, which was distin- 

guished by its larger calyces, petals, and leaves, 

was believed to be confined to southeastern Ohio and 

adjacent Kentucky and West Virginia. In the recent 

literature it has erroneously been referred to as 

G. viscidula var. shortii (Durand) Gleason, and 

G. viscidula var. shortii (Pennell) Gleason. Herbar- 

ium specimens have been examined from throughout the 

range of the species, and mass collections were made 

in Ohio, Kentucky and West Virginia. Examination of 

this material has demonstrated that the sizes of 

petals, calyces and leaves are highly variable both 

throughout the range of the species and within 

individual populations. Subspecific categories are 

unwarranted. 

STANDLEY, LISA A. Department of Biological 

Sciences, Wellesley College, Wellesley MA 02181. 

-Ecotypic variation of stomatal distribution in 

Carex aguatilis Wahl. 

Carex aguatilis Wahl. (section Phacocystis), a 

widely distributed species of temperate marshes and 

wet tundra, exhibits morphological and physiological 

variation across its range. Recent studies of Carex 

aguatilis in the Pacific Northwest have demonstrated 

that foliar anatomy also varies ecotypically. The 

majority of species in sect. Phacocystis have 

stomates restricted to the abaxial surface. The 

leaves of C. aguatilis are typically amphistomous, 

which is presumed to be an advanced character. The 

relative distribution of stomates between the adax- 

ial and abaxial surfaces varies between populations; 

stomates may be entirely or primarily adaxial, or 

may have an equal density on both surfaces. No 

significant variation in stomatal distribution 

occurs within populations, which are also uniform 

with regard to the thickness of leaves, sizes of 

stomates, and total numbers of stomates. Climatic 

factors are strongly correlated with the distribution 

of stomates. Hyperstomous populations occur where 

the average annual precipitation exceeds 60 cm and 

the average July temperature is less than 290C, and 

are coastal and montane. Amphistomous populations 

occur where the climate is drier and warmer and 

water-stress is presumed to be greater, chiefly in 

the Columbia Basin. In the absence of physiological 

adaptation, one way that photosynthetic efficiency 

may be increased in arid habitats in through a 

decrease in the intercellular mesophyll resistance to 

CO2 diffusion. A\mphistomy may be important as a 


means of decreasing the CO2 diffusion distances and 

increasing the rates of uptake, thus increasing the 

photosynthetic efficiency of Carex aguatilis in 

more xeric climates. 

STANDLEY, LISA A. Department of Biological 

Sciences, Wellesley College, Wellesley MA 02181. 

- The taxonomy of the Carex lenticularis complex 

in Central and South America. 

The Carex lenticularis complex forms a distinct and 

probably paraphyletic subgroup within the section 

Phacocystis (Acutae). The combination of nerved 

perigynia with a torulose, stipitate base, irrides- 

cent achenes with ornamented silica-bodies, chromo- 

somal numbers of n=42-46, and narrow amphistomous 

leaves distinguishes this complex. These features 

are shared with the amphiatlantic,Carex nigra group, 

which is distinguished by the hyperstomous leaves. 

Recent studies have shown that the South and Central 

American taxa Carex hermanii, C. cuchumatanensis, 

and C. decidua are included in the C. lenticularis 

complex, based on similarity in morphology, foliar 

anatomy, and the surface patterns of achenes and 

perigynia. Montane and low elevation populations of 

Carex decidua, in South America, and of C. lentic- 

ularis in North America, show similar patterns of 

variation with regard to the sizes of plants and 

colors of pistillate scales and perigynia. Patterns 

of distribution and variation of morphology and of 

anatomy in these species provide information on the 

origin and divergence of taxa of the Carex lentic- 

laris complex, which extends along the western 

Cordillera from Alaska to Tierra del Fuego. 

STEBBINS, G. LEDYARD*, MICHAEL VASEY AND ELIZABETH 

STEVENS. Department of Genetics, University of 

California, Davis, CA 95616. - Chromosome numbers 

and population variation in the Antennaria alpina 

complex in the Sierra Nevada and Cascade ranges. 

In the Sierra Nevada of California, diploid popula- 

tions that were described as A. pulchella Greene are 

sympatric with tetraploid populations that corres- 

pond to A. media Greene. Diploids are generally 

smaller in stature and reproductive structures, 

and differ significantly in other respects. Ecolo- 

gical requirements overlap, but diploids tend to be 

in soils that are better drained. In most of the 

Sierra Nevada, populations are sexual with 

staminate-pistillate ratios approaching 1:1, but 

some populations, particularly those peripheral to 

the area, have an excess of pistillates, up to 100%. 

Populations from the volcanic peaks of the Califor- 

nia and Oregon Cascades are entirely pistillate 

except for those on the Three Sisters, Oregon. 

Diverse habitats close together favor sexual popu- 

lations containing staminate plants; smaller more 

homogeneous habitats widely separated from each 

other contain only pistillate apomicts. 

STEELE, KELLY P. Department of Biological Sciences 

University of California, Santa Barbara, CA 93106 

-Parallel evolution in two species of Gilia (Pole- 

moniaceae)? 

Studies by Verne Grant have indicated that Gilia 

capitata and G. achilleaefolia are two closely relat- 

ed species which are genetically isolated. No Fl 

hybrids have been produced (few seeds are set) in any 

experimental crosses between the two species. How- 

ever, the precise delimitation of the two species


using morphological criteria has always been problem- 

atical. G. capitata as defined by Grant includes 

numerous populations formerly included in G. achil- 

leaefolia. Present studies utilizing experimental 

crosses of previously unstudied populations support 

Grant's delimitation with one important exception. 

G.c.abrotanifolia occurs in the San Rafael Mts. of 

coastal southern California about twenty miles east 

of unambiguous populations of G. achilleaefdlia (the 

species southern limit). The populations from the San 

Rafael Mts. are strikingly different from the coastal 

populations of G. achilleaefolia and are similar to 

populations of G.c.abrontanifolia in the Sierra Ne- 

vada. However, crossing results indicate that indi- 

viduals from the San Rafael Mts. set numerous viable 

seeds with individuals from coastal G. achilleae- 

folia populations (number of viable seeds/number of 

flowers pollinates=2.5) but only occasionally set 

viable seed with individuals from any population of 

G. capitata including G.c.abrotanifolia (number of 

viable seeds/number of flowers pollinated=.4). Re- 

sults for reciprocal crosses are similar. It appears 

that populations of G.c.abrotanifolia in the San 

Rafael Mts. may represent G. achilleaefolia which 

resembles G.c.abrotanifolia. This resemblance could 

result from parallel evolution of similar races with- 

in the two species or from the retention of primitive 

characters from a shared common ancestor. Evidence 

for each hypothesis will be presented. 

SULLIVAN, GENE A* & JULIAN A. STEYERMARK. 

Department of Botany, Louisiana State 

University, Baton Rouge, LA 70803-1705 & 

Instituto Botanico, Apartado 2156, Caracas, 

Venezuela. - 'Rec'ogn'i'tio'n of the genus 

Muzon'ia '(Rubiaceae). 

The genus'Mu'z'on'ia N. Osorio is described as 

containing six species. The genus is found 

in the premontane forests of the northern 

and central Andes and the coastal ranges of 

Venezuela. Three species were previously 

described. Originally placed in Cinchona, 

two Colombian species were transferred to 

Muz'onia by Osorio (1874). These same two 

species were later placed in Ladenbergia by 

Standley, unaware of Osorio's work. Three 

new species are also described. Morpholog- 

ically distinct from other Cinchoneae, these 

species are similar in habit, general and 

pollen morphiology, and habitat requirements. 

However, these species differ in pubescence, 

bract shape and other specific morphological 

characters. Although inconclusive, evidence 

of heterostyly has been noted. 

SULLIVAN, JANET R. Bebb Herbarium, Department of 

Botany and Microbiology, University of Oklahoma, 

Norman, OK 73019 - The questionable status of 

Physalis variovestita-(Solanaceae). 

The biology of Physalis variovestita, a rare Texas 

endemic, and its relationship to P. viscosa were 

examined as part of a systematic study of Physalis 

section Viscosae. Previous studies have noted that 

P. variovestita intergrades morphologically with P. 

viscosa subspecies mollis (composed of var. mollis 

and-var. cinerascens), and that populations of these 

intergrading forms are found throughout eastern 

Texas. An investigation of interbreeding capabilities 

and analysis of the resulting hybrids reveals that 

P. variovestita is genetically more closely-related 

to P. viscosa var. mollis than either taxon is to P. 

viscosa var. cinerascens, This is substantiated by 

pollen ultrastructure and size, flavonoid constitu- 

ents, and a phenetic analysis of thirty-three mor- 

phological features of the three taxa. Based on these 

studies, P. variovestita can no longer be considered 

a species distinct from P. viscosa var. mollis. The 

suggestion that P. variovestita is of hybrid origin 

(P. viscosa var. mollis X P. virginiana var. sub- 

glabrata f. imacrophysa) has been examined but cannot 

be supported or refuted at this time. 

SYTSMA, KENNETH J.* and RICHARD W. PIPPEN. Biology 

Departments, Washington University, St. Louis, MO 

63130 and Western Michigan University, Kalamazoo, 

MI 49008 - Pollination biology and hybridization 

in Neotropical Costus (Costaceae). 

Pollination biology of three sympatric taxa of Costus 

(Costaceae) was studied in the lowland -forest region 

of southern Belize, Central America. Pollen and 

nectar collecting visitors were observed. Nectar 

volumes and sugar concentrations were recorded hourly 

from pre-dawn to mid-afternoon. Amino acid and sugar 

composition of nectar samples were determined for 

each taxon. Costus guanaiensis var. macrostrobilus 

(sect. Costus) is pollinated exclusively by euglossine 

bees, especially species of Eulaema. Costus 

pulverulentus (sect. Ornithophilus) is visited by 

several vectors but most effectively by several 

species of territorial and traplining hummingbirds. 

Costus sp. nov. is an undescribed taxon visited by 

both euglossine bees and hummingbirds. Morphology 

and certain aspects of its pollination biology 

indicate that it most likely arose through hybridization 

between C. guanaiensis and C. pulverulentus. 

SYTSMA, KENNETH J. , BARBARA A. SCHAAL, and PETER 

H. RAVEN. Biology Department, Washington University, 

St. Louis, MO 63130 and Missouri Botanical 

Garden, St. Louis, MO 63166 - Phylogenetics of the 

Lisianthius skinneri (Gentianaceae) species complex 

in Central America. 

Phylogenetic relationships within a geographically 

restricted and morphologically closely related group 

of tropical forest shrubs in the genus Lisianthius 

were analyzed by endonuclease DNA mapping as well as 

with morphology, flavonoids, and allozymes. Eighteen 

populations comprising five species in this group and 

four outgroup species of related Gentian shrubs were 

examined for variation in ribosomal DNA (rDNA). An 

entire cloned rDNA repeat of Glycine (soybean) was 

used as a probe to detect restriction site changes 

and insertions/deletions of DNA. Seven restriction 

enzymes showed at least one site loss/gain in one or 

more of the populations investigated. Variation in 

repeat length among the species is due to insertions 

up to 300 bp long in the non-transcribed spacer 

region of rDNA. Both the restriction site changes 

and the insertions allow construction of a phylogenetic 

tree for the group. These relationships do not 

totally agree with those obtained from other methods. 

All data indicate that evolution within the group has 

occurred from ancestral. mid-elevation L. skinneri 

populations to higher elevation, cloud forest endemic 

species at several different times. Evidence for 

hybridization and introgression between L. skinneri 

and one of the derived spec ies is also documented .

TAYLOR, RONALD J. Department of Biology, 

Western Washington University, Bellingham, WA 

98225 - Patterns and interpretations of variability 

within and among dandelion populations. 

Numerous populations of common dandelions were nonrandomly 

sampled within a broad geographical region 

encompassing the western states of the U.S. and 

British Columbia, Canada. Within each population an 

attempt was made to sample the total range of variation, 

thus involving biotypes indicative of Taraxacum 

officinale and T. laevigatum, when availdble. 

Morphological and chemical variables of sample 

specimens were subjected to multivariant analyses to 

establish the pattern of variation within and among 

populations. Preliminary results reflect considerable 

inter- and intrapopulational variability; 

however, the randomness of the variables indicates 

that most of the variation is explained by phenotypic 

plasticity. Also, the range of variability between 

T. officinale and T. laevigatum was more or less 

continuous weakening the argument for recognition of 

distinct species. Field and greenhouse observations 

suggest that most T. laevigatum characteristics are 

responses to ecological stresses. 

TERRELL, EDWARD E. Plant Exploration and Taxonomy 

Laboratory, Plant Genetics and Germplasm Institute, 

U.S. Department of Agriculture, Beltsville, MD 

20705. 

- Taxonomic implications of spikelet epidermal 

features in Leersia and Oryza (Poaceae). 

Epidermal features on spikelets of species of Leersia 

and Oryza were examined by scanning electron microscopy 

(SEM). Energy dispersive x-ray analysis was 

used to detect the presence of silicon. The most 

important epidermal features of the spikelets occur 

on lemma and palea surfaces (these are similar). 

Leersia lemmas have numerous siliceous triads, each 

consisting of a central round silica body flanked by 

large siliceous tubercles with terminal pits or pores. 

The African species Leersia perrieri, L. tisserantii, 

and L. nematostachya originally were described under 

Oryza but later transferred to Leersia. This study 

confirms the placement of the first two of these 

species in Leersia; the third species is more difficult 

to classify. The approximately 20 species of 

Oryza are more diverse and fall into 5 groups. The 

principal species-group is the 0. sativa (rice) 

complex with approximately 14 species having similar 

lemmatal epidermal configurations. Six other species 

from Africa and Asia fall into 4 groups. Data from 

SEM confirm that two additional species originally 

in Oryza probably belong in separate genera; these 

are Porteresia coarctata and Rhynchoryza subulata. 

THOMPSON, RAHMONA A. Dept. of Botany-Microbiology, 

Oklahoma State University, Stillwater, OK 74078. - 

Generic relationships in the Paniceae: Urochloa 

(Poaceae). 

In the Paniceae, 25 genera are characterized primarily 

by spikelet orientation. The validity of this 

character has been questioned, thus leading to clouding 

of generic boundaries. In a continuing biosystematic 

investigation of this group, 10 species of 

the morphologically variable Urochloa were examined 

using anthecial morphology and epidermal and internal 

leaf anatomy. Urochloa was found to be a distinct 

taxon, but with some intergradation with species of 

Brachi ari a. Antheci al scul pturi ng was hi ghly uni form 

wi th the~ Urochl oa Pattern predomi nati ng . Epi dermal 

features are typically panicoid with narrow inter- 


costal regions. Urochloa has mestome and parenchyma 

bundle sheaths characteristic of the C4, PEP-carboxy- 

kinase photosynthetic pathway. Mesophyll tissue is 

limited to one subradiate ring surrounding the 

vascular bundle. Both laminar surfaces are distinctly 

ribbed; occasionally bulliform fans occur in the 

adaxial rib depressions. 

TOOLIN, LAURENCE J. Department of Geosciences, 

University of Arizona, Tucson, Az. 85721 

- Grasses unmoved by glacier's advances. 

During the past two decades it has been demonstrated 

that fossil packrat middens from the western U.S. are 

an excellent source of plant macrofossils. In dry 

protected sites these middens can persist for thou- 

sands of years. Plant remains thus preserved can be 

dated by the C-14 method. In the past, grass frag- 

ments have been largely overlooked,, since they are 

difficult to recognize and identify. Intensive study 

reveals, however, that grass florets are well pre- 

served and can be determined with a high degree of 

accuracy. Recent work has led to the recovery of 65 

species in 27 genera. The fossils teported here, 

ranging in age from more than 35,000 to 350 years, 

are from the northern Chihuahuan Desert region in 

western Texas and southern New Mexico. These fossils 

demonstrate that many of the grasses growing at the 

sites today have been in place since the pre-full 

glacial mid-Wisconsin. Species with C4 photosynthe- 

sis were present throughout the record, with little 

change in the percentage of C3 species compared with 

modern assemblages. While non-grass plant remains 

from the same middens indicate considerable change 

in other vegetation through time, the grass flora 

apparently remained relatively stable. It is sug- 

gested, therefore, that the growth form and physiol- 

ogy of perennial grasses may make them less sensitive 

to a given change in a climatic regime than trees, 

shrubs, or succulents. The presence or absence of 

C4 grass species in a fossil record may not be as 

reliable an indication of past climates in a given 

area as has been suggested in recent literature. 

Modern grasslands in the Southwest may represent the 

present ecological adjustment of very old, relatively 

stable associations of grasses. 

I?J.SFHEL, NICHOLE, DONALD J. PINKAVA, and 

MARC A. P,AKER*. De,artirenit of Botany & 

Micro!)io.logy, Arizona State University, 

TeCmoe, ArizoLa 85237. - A t.axonontic 

revision of ta e Or)untia whiplei coerlex, 

cactaceae . 

oL untia whip,nIAi circumiscribes three 

varieties: var. whin>)1i, varz. vir-liflEor 

an&d var. multiitniculaLa. The latter two 

are believed to have ariseni through 

interspecific or possibly intersectionial 

hybridizat ion. We have Found good evidence 

t1lat 0. whii.ljei var. whiLlei hybridizes 

wi th 0 iepQocaulis and 0. acanthoc'a Va 

t hornberi. PreliminaLy data have also 

revealed 0. wliDt)ei var. whip?lei to be 

involved in intraspecific polyploid-. Most 

of the 1ants are di-loid, while a 

tetra ioid cace exists in northwesterii 

Arizona. Chromosoiwe uiiubers of the other 

varieties are yet to te determiined. Field 

and laibrtitory studies will i ncl.ule 

chlaracter iueasure-uent aa d anaia sis, 

c togenetic an%.alysis, seed viability, poller, 

st ainabi li ty and det ernina ti on o f ecoIlo ic aI 

p?arameters.*


UMBER, RAY E. Department of Botany, University 

of Wyoming, Laramie, WY 82071. 

- Pollinator size as a factor in Penstemon 

strictus flower evolution. 

Penstemon strictus Bentham subspecies strictus is a 

plant species found in Wyoming, Colorado, New Mexico, 

Arizona, and Utah in a wide variety of habitats from 

about 6,000 to 11,000 feet of elevation. Within this 

one taxon one can find a great deal of variation in 

flower size. Corollas can range in size from 21 mm 

to as much as 45 mm in length. Differences in shape 

can also be seen. In an effort to understand the 

diversity in the flower sizes and shapes seen in P. 

strictus field studies were begun to first establish 

that differences in flower parameters existed between 

populations and secondly to establish differences between 

populations in terms of pollinator suites. 

Significant differences in flower sizes and shapes 

were found between different populations of P. 

strictus and differences were also found in the 

pollinator suites. Penstemon populations with large 

pollinators were also characterized by the larger 

flowers as expected. Pollinator size is then judged 

to be an important factor in the evolution of the 

genus Penstemon. 

VARADARAJAN, G. S.* and GREGORY K. BROWN. 

Department of Botany, Ownbey Herbarium, 

Washington State University, Pullman, WA 99164. 

- Re-evaluation of the classification of 

Phytolaccaceae s. lat. 

The generic composition of the Phytolaccaceae Lindl. 

has long been controversial, and past treatments 

reveal a variety of familial circumscriptions and 

intrafamilial classifications. Central to the 

controversy are the genera Achatocarpus and Phaulo- 

thamnus, Agdestis, Barbeuia, and Stegnosperma, which 

have been treated within the Phytolaccaceae s. lat. 

or as components of the Achatocarpaceae Heimerl, 

Agdestidaceae Nak., Barbeuiaceae (Baill.) Nak., and 

Stegnospermaceae (H. Walter) Nak. respectively. In 

hope of resolving controversy over the delimitation 

of Phytolaccaceae, we applied Wagner Network and 

UPGMA cluster analysis algorithms to a data matric 

of 34 characters for each of the 20 genera that 

comprise Phytolaccaceae s. lat. The results indicate 

well-defined groups of genera, and suggest the need 

for recognition of Phytolaccaceae s. str.-(Anisomeria, 

Ercilla, Gisekia, Phytolacca), Petiveriaceae (Gall- 

esia, Hilleria, Ledenbergia, Lophiocarpus, Microtea, 

Monococcus, Petiveria, Rivina, Schindleria, Seguieria, 

Trichostigma), Achatocarpaceae (Achatocarpus and 

Phaulothamnus), and the three monogeneric families 

Agdestidaceae, Barbeuiaceae, and Stegnospermaceae. 

The analysis also points out the need for further 

research regarding the treatment of Microtea, Lophio- 

carpus and Monococcus, genera tentatively included 

within the Petiveriaceae. 

VODICKA-ASBURY, MARGARET R. L. H. Bailey 

Hortorium, Cornell University, Ithaca, NY 

14853. - Preliminary investiqations into 

the systematics of the tribe Prockieae 

(FIacoutiaceae). 

The tribe Prockieae, as recently circum- 

scribed by Sleumer, comprises eight neotrop- 

ical genera. This circumscription has a 

historical basis in Warburg and Gilg (Engler) 

although alternative classifications have 

been proposed. Those of Bentham and Hooker 

and of Hutchinson divide the genera into two 

groups, one assigned to the Flacourtiaceae 

and the other, to the Tiliaceae. A range of 

placentation types from parietal to intruded 

parietal to secondarily axile has played a 

too important role in placement of the genera. 

Distributions of character states determined 

from detailed anatomical studies of leaves 

(especially stomate characters) and from 

anatomical studies of ovary development, as 

well as characters in the literature on wood 

anatomy (Miller) and pollen morphology 

(Keating) are not congruent with distribu- 

tions of placentation type. Resolution of 

the problem of placement of these genera can 

only be accomplished in a phylogenetic con- 

text, based on a wide array of characters. 

WALLACE, ROBERT S.* and DAVID E. FAIRBROTHERS 

Department of Biological Sciences - Botany Unit 

Rutgers University, Piscataway, N.J. 08854. 

- Population comparisons using isoelectrically 

focused seed storage proteins of Opuntia humifusa 

(Raf.) Raf. 

Morphological studies of the eastern prickly-pear 

cactus, Opuntia humifusa show it to be a highly 

polymorphic species. To determine the similarity 

indices between closely and widely distributed 

populations having morphological differences, the 

use of isoelectric focusing electrophoresis was chosen 

because of the high resolution capability of this 

separation method. Seeds of fifteen populations of 

0. humifusa were collected ranging from Long Island, 

NY tonorthern Florida representing different physiographic 

areas. The seeds were de-coated by hand in 

a mortar and pestle and the resulting endosperm - 

embryo containing meal was de-lipified in cold (0WC) 

acetone. Proteins were extracted in a TRIS-glycine 

buffer (pH 8.4) and separated in a 7% polyacrylamide 

gel in which BioLyte ampholytes were added to produce 

an anode to cathode pH gradient from 3 to 10 respectively. 

Staining was accomplished using Coomassie 

Brilliant Blue general protein stain and enzymatic 

stains for EST, APH, and ADH. In comparisons between 

the populations, high (> 0.80) indices of similarity 

were found when based on isoelectrically focused 

proteins. The resolution obtainable with this method 

also was sufficient to detect differences between 

nearby populations having slight or no apparent 

morphological differences. It can be concluded that 

0. humifusa is a single species throughout its range 

and that isoelectric focusing electrophoresis may be 

used as a high resolution separation tool for analysis 

and comparison of seed storage proteins in the 

Cactaceae. 

WARNOCK, MICHAEL J. Department of Biology, 

Sam Houston State University, Huntsville, Texas 

77341.--Natural hybridization between Delphinium 

treleasei and D. caroZinianwn (Ranunculaceae). 

Delphinium treleasei Bush ex Davis and D. 

carolinianum occur symipatrically on the Ozark Plateau 

of southwestern Missouri and northwestern Arkansas. 

Delph.inium treZeasei is a locally common endemic to 

the region, occurring only in juniper "glades" on 

outcrops of Cotter dolomite. Delph.inium 

carolinianu is a widespread species found from the 

south Atlantic states to the foothills of the Rocky 

Mountains as well as in the Ozarks. Ecologically,

considerable overlap is observed between the species. 

Although D. treZeasei is usually found in slightly 

thinner, rockier soils than D. caroZinianwn, mixed 

populations are occasionally seen and discrete 

populations within 100 m of each other are common. 

Phenologically, the period of overlap of anthesis is 

about two weeks. Visitors to both species include 

bumblebees, butterflies and hawkmoths. Over the last 

five years, four putative natural hybrid plants have 

been discovered. These putative hybrids show inter- 

mediacy in morphological and flavonoid characters as 

well as nearly completely unstainable pollen and no 

seed set. The intermediate plants were each found in 

populations of D. treZeasei with nearby populations 

of D. caroZinianum. Artificial crosses were attemp- 

ted using each species as a pollen donor. All 

attempts were unsuccessful. A substantial genetic 

barrier between the species is indicated. This is 

quite unlike results by other workers (Epling & 

Lewis) on hybridization in DeZphinium. A third 

species, D. tricorne Michaux, also occurs in the 

region, with populations often quite near those of 

D. treZeasei and D. caroZinianwn. Due to differences 

in flowering phenology, no opportunity for hybridiza- 

tion between D. tricorne and the other taxa was seen. 

WARWICK, S.I. and L.D. BLACK. Biosystematics Res. 

Inst., Agriculture Canada, Ottawa, Ontario KiA OC6. 

- Genecological studies of a new problem-weed in 

Canada, Sorghum halepense (Johnson grass). 

Thirteen populations of Sorghum halepense were 

sampled from fields in Ontario, Canada and Ohio and 

New York in the U.S.A. Four populations were reported 

to overwinter as rhizomes but the others do not. 

The morphology, phenology, resource allocation patterns 

and growth of seedling and mature plants grown 

in a 5-month greenhouse cultivation trial were examined 

for differences between the overwintering and 

the non-overwintering biotypes and between populations 

within biotypes. Fifty characters were scored, 

7 from field collected material and the rest from 

plants grown in the greenhouse. Field collected 

specimens showed phenotypic differences between biotypes, 

with the non-overwintering populations having 

larger seeds, wider culms, and leaves, and larger 

inflorescences (p

136 Teaching Section 

explain the available data. Normally cladists prefer 

the hypothesis of relationship requiring the fewest 

character state transformations, i.e. the most 

"parsimonious" hypothesis. We demonstrate that it is 

sometimes possible to reduce the total number of 

steps by introducing one or more reticulations into 

an otherwise hierarchic cladogram. If one is allowed 

to invent "donor organisms" then all incongruence in 

data sets can be explained as having resulted from 

reticulation. These observations focus attention on 

the need to consider what additional information or 

criteria can be used to decide when it is appropriate 

to invoke hierarchy and when reticulation. Inform- 

ation concerning geographic ranges, the constitution 

of genomes, and experimental hybridizations can all 

bear on this decision, but it is unclear exactly how 

these data should be added to the character data in 

arriving at an overall parsimony decision. To clearly 

formulate this problem we contrast a case in which 

reticulation is an implausible explanation with one in 

which it seems highly likely. Although it may be 

impossible to develop any universally applicable rules, 

we can formulate a set of general guidelines for 

deciding when reticulation should be considered. 

YOUNG, DAVID A. L. H. Bailey Hortorium, 

Cornell University, Ithaca, New York 14853 

- Vesselless Angiosperms: Character 

weighting and the pan-parallelism paradigm. 

Resurrection of the hypothesis that woody 

members of the Magnolianae (sensu Takhtajan) 

are not primitively vesselless has, as expe- 

cted, generated considerable controversy, 

and criticisms of the hypothesis recently 

have appeared in various publications. Most 

of the criticisms leveled so far have fo- 

cused on three principal areas: 1) disagree- 

ment with the assumptions and methods of 

Hennigian cladistic analyses; 2) disagree- 

ment with circumscription of the original 

study group and character delimitation; and 

3) the apparent lack of adaptive value of 

losing the "highly adaptive" vessel (i.e., 

vessel member). Each of these areas of dis- 

agreement will be addressed in the context 

of a cladistic analysis of the Magnolianae. 

It is suggested that the vesselless con- 

Luella Weresub Memorial Lecture: Fungi as 

Botanists 

PIROZYNSKI, K.A. National Museums of Canada 

(NMNS), Ottawa, Ont. KlA OM8, Canada. 

-Fungi as botanists. 

All living organisms are taxonomists, and the 

biotrophs, like human taxonomists, are concerned 

with systematics of living organisms. However, 

unlike a human taxonomist, they cannot afford to 

make mistakes, but have had millions of years of 

experience in discovering morphological, physio- 

logical, biochemical and ecological characters 

which often remain hidden to our eyes and minds. 

TEACHING SECTION 

dition belongs to a unique class of weighted 

characters in that it is not used by evolu- 

tionary systematists to define higher taxo- 

nomic groups within the angiosperms (i.e., 

it is a weighted plesiomorphic feature). 

Assumptions inherent in assuming plesiomor- 

phic vessellessness within the angiosperms 

will be considered in the context of the 

"pan-parallelism" paradigm that seems to 

prevail in angiosperm systematics. It will 

be argued that parsimony should prevail over 

either a priori or a posterori character 

weighting. Finally, the "adaptive value" of 

vessellessness will be considered. 

ZULOAGA, FERNANDO 0. * and THOMAS R. SODERSTROM. 

Instituto de Botanica Darwinion, San Isidro, 

Republica Argentina and Department of Botany, 

Smithsonian Institution, Washington, D.C. 20560. 

- Disposition of the "outlying" species of the 

genus Panicum (Poaceae: Paniceae) from tropical 

America. 

During studies leading to a revision of the species 

of Panicum from Central and South America, we analyzed 

the following taxa of dubious placement within 

the genus: P.glutinosum Swartz, P.villaricense Mez, 

P.macranthum Trinius, P.aristellum Doell, P.arnacites 

Trinius, P.megastachyum Nees and P.grandifolium 

Doell. Our findings indicate that 

- P.glutinosum & P.villaricense should be transferred 

to Homolepis, bringing the number of species in the 

genus to five; 

- P.macranthum should be included in Streptostachys, 

a genus previously consisting of one species and 

now comprising 

species; 

S.macrantna, S.asperifolia and a new 

- P.grandifolium should be transferred to Ichnanthus; 

- P.aristellum & P.arnacites present clearly different 

characteristics in relation to Panicum and 

should be considered as two new genera in the 

Paniceae; and 

- P.megastachyum includes two species under the same 

name, both of which should be transferred to 

Brachiaria. 

The correct disposition of these outlying species 

allows 

itself. 

a further clarification of the genus Panicum 

As obligate carbon heterotrophs the fungi have been 

intimately linked with plants throughout their long 

history, and provide particularly good examples of 

tightly co-evolved biotrophic relationships, both 

parasitic and mutualistic. 

How meaningful the associations are will depend on 

how well we can distinguish between the biotroph as 

a taxonomist and the biotroph as an opportunist. 

Nevertheless, taxonomic data derived from studies 

of such complex interactions are likely to be more 

critical and objective than those based on a 

systematist's morphological interpretations which 

are the traditional tools of systematics and 

biogeography.

Special Lecture: Reproductive Biology of the 

Flowering Plants 

MEKUSB, BAST -AAN J. D. Delpartmaent of Botany, 

UniversiLv of 11ashAngJonp Seattle, 1iA. 98195. 

Reprodact4ve bioloy oL -the flowioJerin; pants. 

The studly of pol1ina1Jio- and seed-disers,al, once 

considered an innocenb nastile for retired schoolteachlrs, 

'rovidi-nc 

now occupies 

new concepts 

a central position in biology, 

as well as demonstraL.r 

material to such diverse areas of ivosti-'Qi .Las 

co-*erro-i. c, morphoenresi-s, entomoli -.P,-y, 

Jo laa'on--d-. cn.t-n biocn: m Aic-try, animal & plant 

phlys-1Loogyr., forag-, n-S rat .-gles, cost-b - 81zn' fit 

relationsheihn-, and otlerso. In the prese.-iltu sympor ouam, 

c.;llhasi:, irill be nl3ac'd unoon some case-hiutorl.es 

whichi eac'1 h'ro-thv contr-bouted to variec disecimes - 

i' a s' grU ! '- m n'-ar The art 'i lily f xmA n as 

provided. the ciuassical and most spectculi-i;> ex apqles 

of cyade - i and thenr-cgmnic resc'ra'tioz;. 

onme of its .embeors, collL;nv4ed by urr-eg s-3, t 

displ,y mc' a- in' r1S in the geruas Arisa>n, 

se3x-chi a. ca eaxr bn s-uriaed Lin In the 

O r c 1 t.i i.d m:s,C tht a r nt_ discov re:r t?1hat t. 'le ocior of 

the flo-rers of Orcu-hi l . a c3 that 1o' the 

feina]u)s of cert;. ln. -riid bees ar3d at+r- tine t al-u- 

(but not th- feronialst' of thesm i nsacts just'ifi es 

the conlcsrn:LIcm that 0. ca n c se-ri s a 

''sLE1

138 Teaching Section 

comparison of the TLC behavior of three giibberellins 

run on i) normal phase silicic acid adsorbant and 

ii) reverse-phase material. Visualization of 

chromatograms and calculation of Rf values of the 

separated components will be by UV fluorescence. 

B) Bioassay. Two bioassay systems will be 

demonstrated i) Lettuce hypocotyl and ii) Dwarf rice. 

Dose-responses to both unchromatographed and TLC 

chromatographed standards will be presented for both 

assays. Dose-response curves for both assays will 

be prepared. C) Extraction. A very rich, eAsily 

extracted source of gibberellins is the immature 

fruits of Scarlet Runner or Kentucky Wonder beans. 

The preparation of the extract and its assay will 

be described. CYTOKININS. Bioassay. Two bioassay 

systems will be demonstrated. i) Soyabean hypocotyl 

slice assay and ii) Amaranthus betacyanin synthesis 

asssay. The latter system calculates betacyanin 

levels through measures of spectrophometric absorb- 

ance at 542 and 620 mp. Dose-response curves will 

be prepared. 


GERRATH, JEAN M.* and U. POSLUSZNY. Department 

of Botany and Genetics, University of Guelph, 

Guelph, Ontario, Canada NlG 2W1. 

- The use of videotape introductions to 

facilitate consistency in multi-sectioned 

laboratories. 

In response to some of the problems of ensuring 

consistency in teaching a large laboratory course 

in introductory botany, a series of videotape 

introductions to labs was made. In these, the work 

to be covered is outlined, the main objectives are 

stressed, and techniques such as freehand section- 

ing are demonstrated. These tapes have meant that 

students can now see and hear the introductions 

clearly, and that all sections are given the same 

information. Students are apparently more able to 

work independently through their lab manual 

exercises and to perform the necessary techniques 

more easily than they did under the more tradi- 

tional system. Demonstrators with varying 

proficiencies in public speaking are no longer 

required to give the introductions. A demonstra- 

tion of one of the tapes will take place and a 

discussion of the procedures used to produce them 

will ensue. 

DWIGHT T. KINCAID. Depart. of Biol. Sciences. 

Lehnan College, CUNY, Bronx, NY 10468 - 

Micro-cormputer assisted instruction in biometry 

using botanical data. 

I present programs which teach bionretry by using my 

research data to illustrate topics in frequency 

distributions, derived variables, data smoothing, 

correlation, regression, AN4OVA, and nonparametric 

methods. Our graduate students relate well to 

statistical treatmients of data bases including 

morphometrics of leaves, quadrats, distribution of 

tree size, aind micro-meteorology. The programs are 

largely in BASIC, are implemented on the Apple II, 

and are available free on discs. Students are given 

these prograns and told to use then as supplement and 

drill following class lectures. Each program takes 

about 30 mainutes with timing under student and 

program control; scrol ls text; provides graphic 

images and questions graded by the program; and 

provides bibliographies. To operate them requires no 

more than to type, run. WJhile the sane raw 

information could be given by mimeographed handouts, 

students find it more fascinlating to watch text 

scroll anld garaphics fade-in, overlay, and fade-out. 

Timing and pause are crucial. Program execution halts 

until students enter their guess for say, the 

correlation coefficient of a scatterplot. the 

influence of an outlier on a regression line, whether 

2 frequency distributions are different, or whether a 

histogram has a normal distribution. Drill is 

important in learning how to analyze biological data. 

so during program execution there are opportunities 

to backup; and at the end, all graphs used to 

illustrate various points, fade in and out 

sequentially. While computer assisted instruction is 

not difficult to code, it is indeed time consuming 

for the programier. However, the structure one adopts 

can then be modified to create computer assisted 

instruction in other subjects. These programs are 

compatible with my menu-driven package of programs 

presented to the teaching section at AIBS last year. 

A new release is available since corrections; 

improvements in speed, memory utilization, and 

program executed documentation; and new programs have 

been added. 

KRUPP, JONATHAN M. Department of Botapy,University 

of California, Davis, California 95616. - The 

selection and operation of color television equip- 

ment for use in botany laboratory courses. 

Color television systems for use in botany laboratory 

courses must be selected with an understanding of 

the capabilities of the equipment and the abilities 

of the potential users. Basic equipment for such a 

system consists of a color video camera and lens, 

a trinocular compound microscope with a C - mount 

camera adapter and light balanced objectives, a video 

tape recorder, and a color monitor / receiver. In 

addition, a wide variety of equipment is available 

which can provide pointers, text, or other markers on 

the TV screen. Specifically, cameras with automatic 

white balance and video output controls and separate, 

low mass pick-up tubes are the most suitable. Due to 

its greater resolution and compatability with other 

video media, the 3/4", U-matic cassette is the most 

useful tape format. Compact equipment, mounted on 

portable carts allows greater flexibility and util- 

ization of the system without the need for extensive 

dedicated space. Applications for such a system 

include the production of review tapes for use by 

students and faculty, use as a multiple viewer micro- 

scope system for group discussions, and as a medium 

for preserving and exchanging images of rare and/or 

ephemeral specimens over time and distance. Sample 

tapes produced during laboratory courses will be 

available for review and the possibility of establishing 

sidered. 

a video tape exchange network will be con- 

MUILLINSM, J4ENI?L S.* and JOHI4 A. NOVAK. Biologi- 

cal and Elnvironmenital Scienices, California Uni- 

versity of Perunsylvania, Califonlia, PA 15419 

and Sciaece and Math Education, Thie Ohiio State 

Universit-yz, Colmbus, OH 43210. 

- Thle hay inlfusion - a teaclhingj tool for nastery 

learning In freshuman b.otany. 

B16TiTs IIasLery Learning technique forms thle framre- 

work; inT w7hich fresisnau botany is taught at Califonlia 

University of P13onisylvania. Lecture subject matter 

is arraiged hi learning Lunits w1IcaCil ar-e reinforce-l 

in thic lal.)oratory. Awufgrintation of 1lecture material 

is primarily by ieans of the lay infusion, %which each 

student cultures as a see-ster-long project. Loam- 

inlC units illustrated by the infusionl are: 1) succes- 

sionl 2) abJiotic factors 3) organism interactions 

4) food dhains 5) aseptic technlique 6) living3 J cteria 

7) bacterial cultuLres 83) bacterial identification, 

9) blue-green bacteria 10) diatoms 11) green algae.

Studclnts are recauired to write a t:erm paper, in 

scientific formt oli th-eir own hay infusion. In 

keeping with Bloorm's tenets, students score hicgl on 

these tenn )alers. Bloomr's curve of extinction is 

aclhieved for all lecture exzrmi grades. 

ORR, ALAN R. Department of Biology, 

University of Northern Iowa, Cedar Falls, 

IA 50614. 

- Microscopic identification of metabolic 

pathways in plant tissues. 

I 

Metabolic pathways are the means by which cells 

obtain their building block molecules and their 

energy of life to do the work of living. Often it 

is difficult for the student to relate lectures 

about energy transducing pathways to the actual 

plant tissues. Microscopic "visualization" of 

biochemical pathways offers a challenging way for 

students to better comprehend plant metabolism. 

Techniques will be described for the preparation of 

fresh-frozen cryostat sections of plant tissues and 

the localization of enzymes as markers for the 

pentose phosphate pathway, citric acid cycle pathway 

and the electron transport pathway. Some basic 

relationships to plant development will be presented. 

PLATT, ROBERT S., JR. Department of Botany, Ohio 

State University. Columbus, OH 43210. 

- The fixation of carbon and nitrogen: flawed 

gas-grabbing systems. 

Botany courses today can make a major contribution to 

the understanding of energy-efficient food production 

in our energy-limited world. Two botanical processes 

are fundamental in this discussion: the photosynthetic 

fixation of carbon dioxide, and the fixation of 

dinitrogen, particularly that by legume root nodules 

and blue-green algae. These processes have interesting 

similarities. Both start with a complex enzyme 

(RuBP carboxylase and nitrogenase) that has an affinity 

for specific atmospheric gases (CO2 and N2), and 

both reactions are driven by ATP and a strong reductant. 

Furthermore, the efficiency of both enzymes is 

severely inhibited by molecular oxygen. Neither enzyme 

appears to be well adapted to modern atmospheres. 

(The parallel ends, of course, with an analysis of 

the specific mechanisms of oxygen inhibition.) The 

development of strategies to overcome this systematic 

flaw, however, would appear to be a primary objective 

both in natural selection, as evidenced in the recent 

Teaching Section 139 

evolution of C4 photosynthesis, and for the genetic 

engineering of nitrogen fixing systems into plants 

other than legumes and algae. 

SUNDBERG, MARSHALL D. Department of Biology, 

University of Wisconsin, Eau Claire, WI 54701 

- Stereological analysis of sun and shade leaves 

in general botany. 

Stereology is the study of three dimensional objects 

through the interpretation of two dimensional images. 

Its primary use in biology has been to analyze 

ultrastructural aspects of plant and animal cells. 

The basic techniques of stereology are simple and may 

be applied to the analysis of cells with the light 

microscope. The paper describes the procedure used 

in a general botany course to quantitatively analyze 

the volumes of different cell types in sun and shade 

leaves. These data support the qualitative 

descriptions of sun and shade leaf anatomy found in 

most general botany texts. 

WESTERLING, KARIN E.* and THOMAS C. WILSON. 

Department of Developmental and Cell Biology and 

Instructional 

California, 

Development Services, University 

Irvine, CA 92717. - Some factors 


affecting student perceptions of instructor 

teaching ability. 

End-of-term teaching evaluations by students are used 

extensively as a measure of instructor teaching 

ability. Since information concerning instructor 

proficiency may then be used as a basis for course 

assignments, promotion, and/or rehiring decisions, 

it is important to determine whether student 

evaluations are valid and reliable. Fortunately, 

reliability is amenable to statistical analysis. 

End-of-term teaching evaluation instruments for 

biology teaching assistants were administered to 

undergraduate students. The students' evaluation of 

instructor performance is correlated with factors 

which are often thought to affect student perceptions 

of teaching quality. Students' expectation of course 

grade, perceptions of course difficulty, and 

estimation of gained reasoning skill are correlated 

with their impressions of instructor ability.

Abstracts of Papers - Harvard Forest - Harvard University

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