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Janice Glimn-<strong>Lacy</strong><br />
6810 Shadow Brook Court<br />
Indianapolis, IN 46214-1901<br />
USA<br />
janglimn@umich.<strong>ed</strong>u<br />
Library <strong>of</strong> Congress Control Number: 2005935289<br />
ISBN-10: 0-387-28870-8 eISBN: 0-387-28875-9<br />
ISBN-13: 978-0387-28870-3<br />
Print<strong>ed</strong> on acid-free paper.<br />
Peter B. Kaufman<br />
Department <strong>of</strong> Molecular, Cellular, and<br />
Developmental Biology<br />
University <strong>of</strong> Michigan<br />
Ann Arbor, MI 48109-1048<br />
USA<br />
pbk@umich.<strong>ed</strong>u<br />
C○ 2006 Janice Glimn-<strong>Lacy</strong> and Peter B. Kaufman<br />
All rights reserv<strong>ed</strong>. This work may not be translat<strong>ed</strong> or copi<strong>ed</strong> in whole or in part without the written permission <strong>of</strong> the publisher (Springer<br />
Science+Business M<strong>ed</strong>ia, Inc., 233 Spring Street, New York, NY 10013, USA), except for brief excerpts in connection with reviews or scholarly<br />
analysis. Use in connection with any form <strong>of</strong> information storage and retrieval, electronic adaptation, computer s<strong>of</strong>tware, or by similar or dissimilar<br />
methodology now known or hereafter develop<strong>ed</strong> is forbidden.<br />
The use in this publication <strong>of</strong> trade names, trademarks, service marks, and similar terms, even if they are not identifi<strong>ed</strong> as such, is not to be taken<br />
as an expression <strong>of</strong> opinion as to whether or not they are subject to proprietary rights.<br />
Print<strong>ed</strong> in the Unit<strong>ed</strong> States <strong>of</strong> America. (TB/MVY)<br />
987654321<br />
springer.com
Preface<br />
This is a discovery book about plants. It is for everyone<br />
interest<strong>ed</strong> in plants including high school and college/<br />
university students, artists and scientific illustrators,<br />
senior citizens, wildlife biologists, ecologists, pr<strong>of</strong>essional<br />
biologists, horticulturists and landscape designers/architects,<br />
engineers and m<strong>ed</strong>ical practitioners, and<br />
physical therapists and their patients. Here is an opportunity<br />
to browse and choose subjects <strong>of</strong> personal interest,<br />
to see and learn about plants as they are describ<strong>ed</strong>.<br />
By adding color to the drawings, plant structures become<br />
more apparent and show how they function in<br />
life. The color code clues tell how to color for definition<br />
and an illusion <strong>of</strong> depth. For more information, the text<br />
explains the illustrations. The size <strong>of</strong> the drawings in<br />
relation to the true size <strong>of</strong> the structures is indicat<strong>ed</strong><br />
by × 1 (the same size) to × 3000 (enlargement from<br />
true size) and × n/n (r<strong>ed</strong>uction from true size).<br />
The contents reflect a balanc<strong>ed</strong> selection <strong>of</strong> botanical<br />
subject matter with emphasis on flowering plants,<br />
the dominant plants <strong>of</strong> the earth. After a page about<br />
plant names and terms, the book is divid<strong>ed</strong> into three<br />
sections. The first is an introduction to plants, showing<br />
structure and function; then, major groups, providing<br />
an overview <strong>of</strong> the diverse forms; and lastly, oneseventh<br />
<strong>of</strong> the flowering plant families, with the accent<br />
on those <strong>of</strong> economic importance. The sequence in the<br />
sections is simple to complex (cell to se<strong>ed</strong>), primitive to<br />
advanc<strong>ed</strong> (blue-greens to flowering plants), and unspecializ<strong>ed</strong><br />
to specializ<strong>ed</strong> (magnolias to asters and waterplantains<br />
to orchids). Where appropriate, an “<strong>of</strong> interest”<br />
paragraph lists ways these genera are relevant in<br />
our lives (categories include use as food, ornamentals,<br />
lumber, m<strong>ed</strong>icines, herbs, dyes, fertilizers; notice <strong>of</strong> wild<br />
or poisonous; and importance in the ecosystem). “Of<br />
interest” sections in <strong>Botany</strong> <strong>Illustrat<strong>ed</strong></strong>, second <strong>ed</strong>ition,<br />
have been expand<strong>ed</strong> to include many more topics <strong>of</strong><br />
interest.<br />
Evolutionary relationships and the classification <strong>of</strong><br />
plants have been undergoing many changes in the past<br />
two decades since the first <strong>ed</strong>ition. In this <strong>ed</strong>ition controversial<br />
categories have been eliminat<strong>ed</strong> allowing individuals<br />
to be expos<strong>ed</strong> to current thinking on plant classification.<br />
Classification from this second <strong>ed</strong>ition may<br />
be found in the <strong>Index</strong> under “Fungi Kingdom” and “Plant<br />
Kingdom.” Pages on bacteria have been eliminat<strong>ed</strong> and<br />
two new pages on plant fossils, with accompanying illustrations,<br />
have been add<strong>ed</strong>. Every text page has undergone<br />
extensive revision.<br />
For those interest<strong>ed</strong> in the methods us<strong>ed</strong> and the<br />
sources <strong>of</strong> plant materials in the illustrations, an explanation<br />
follows. For a developmental series <strong>of</strong> drawings,<br />
there are several methods. One is collecting several<br />
specimens at one time in different stages <strong>of</strong> development;<br />
for example, several buds and flowers <strong>of</strong> a plant<br />
(see 29) and button to mature forms <strong>of</strong> mushrooms (see<br />
50, 51). Then, some are cut open to observe parts and<br />
decide how to present them, while others are to use for<br />
final drawings. Another method is waiting for the plant to<br />
change, which involves “forcing” stems (see 14), germinating<br />
se<strong>ed</strong>s (see 40), watching one leaf expand (see<br />
69), and drawing a flower in one season and its mature<br />
fruit in another (see 104, 109, 110, 111). An alternative<br />
to waiting for fruit is to use a collection <strong>of</strong> dry or frozen<br />
specimens, so that as spring flowers appear, the later<br />
maturing fruits can be seen at the same time (see 102,<br />
105, 106).<br />
In the first section, introduction to plants, there are several<br />
sources for various types <strong>of</strong> drawings. Hypothetical<br />
diagrams show cells, organelles, chromosomes,<br />
the plant body indicating tissue systems and experiments<br />
with plants, and flower placentation and reproductive<br />
structures. For example, there is no average or<br />
standard-looking flower; so, to clearly show the parts<br />
<strong>of</strong> a flower (see 27), a diagram shows a stretch<strong>ed</strong> out<br />
and exaggerat<strong>ed</strong> version <strong>of</strong> a pink (Dianthus) flower<br />
(see 87). A basswood (Tilia) flower is the basis for<br />
diagrams <strong>of</strong> flower types and ovary positions (see<br />
28). Another source for drawings is the use <strong>of</strong> prepar<strong>ed</strong><br />
microscope slides <strong>of</strong> actual plant tissues. Some<br />
are trac<strong>ed</strong> from microscope slide photographs such<br />
as cross-sections, vascular bundles, and transections.<br />
Scanning and transmission electron micrographs are<br />
trac<strong>ed</strong> for chloroplasts, amyloplasts, trichomes, internodes,<br />
and pollen grains. Preserv<strong>ed</strong> museum specimens<br />
provide the source for animals in the pollination series.<br />
The remainder <strong>of</strong> the drawings are from actual plants<br />
found in nature, the grocery store, plant nurseries, farm<br />
fields, botanical gardens, florist shops, and suburban<br />
yards.<br />
In the major groups section, three pages have hypothetical<br />
diagrams, indicat<strong>ed</strong> in the captions. Other microscopic<br />
forms are from observations <strong>of</strong> living material or<br />
prepar<strong>ed</strong> microscope slides. For plants not locally available,<br />
dry-press<strong>ed</strong> herbarium specimens are measur<strong>ed</strong><br />
for drawings (Stylites, Helminthostachys, Gnetum, and<br />
Eph<strong>ed</strong>ra) or machine-copi<strong>ed</strong> and trac<strong>ed</strong> (habit drawings<br />
v
<strong>of</strong> filamentous algae) or chemically reviv<strong>ed</strong> to three<br />
dimensions (bryophytes) for drawing with the use <strong>of</strong><br />
a dissecting microscope. Drawings are also made<br />
from liquid-preserv<strong>ed</strong> specimens (Tmesipteris habit,<br />
Welwitschia and Ginkgo reproductive structures). For<br />
the majority <strong>of</strong> this section’s drawings (including Welwitschia<br />
habit), living organisms are us<strong>ed</strong>.<br />
vi<br />
For the flowering plant families section, except for two<br />
indicat<strong>ed</strong> diagrams in the grass family, all the drawings<br />
are from actual plants glean<strong>ed</strong> from fields, forests, roadside<br />
ditches, bogs, neighbors’ yards, botanical conservatories,<br />
florist shops, grocery stores, and our gardens.<br />
The bumblebee arriv<strong>ed</strong> <strong>of</strong> its own accord.<br />
Janice Glimn-<strong>Lacy</strong><br />
Peter B. Kaufman
Color Code Clues<br />
The illustrations may be color<strong>ed</strong> by using the easy-t<strong>of</strong>ollow<br />
Color Code. Each drawing has lines from structures<br />
to letters, duplicat<strong>ed</strong> in the Color Code. All structures<br />
similar to the one with a line and letter are the<br />
same color; for example, only one <strong>of</strong> five petals may be<br />
identifi<strong>ed</strong>. Color<strong>ed</strong> pencils are recommend<strong>ed</strong> for pleasing<br />
results. My personal preference is Berol Prismacolor<br />
pencils. The colors ne<strong>ed</strong><strong>ed</strong> are 2 shades <strong>of</strong> r<strong>ed</strong>,<br />
green, and blue, and 1 each <strong>of</strong> orange, yellow, pink,<br />
purple, brown, and black. Sometimes the Color Code<br />
lists double colors such as yellow-green, r<strong>ed</strong>-brown, or<br />
purple-green. Color the same area with a light touch <strong>of</strong><br />
both colors for the closest resemblance to the plant’s<br />
natural color. A black pencil us<strong>ed</strong> lightly provides a gray<br />
color. White is to remain blank. Using pink over light<br />
purple results in a lavender color. So as not to color<br />
areas that are to remain white or have small areas <strong>of</strong><br />
color, follow the order list<strong>ed</strong> in the Color Code foranindividual<br />
drawing. Letters, missing from the Color Code,<br />
are in the text. They usually indicate structures shown<br />
as black outlines or colorless areas.<br />
When drawing a 3-dimensional object, scientific illustrators<br />
traditionally use an upper-left light source on the<br />
object, which casts shadows on the lower right. Converting<br />
those shadows into ink dots (stipple) and lines<br />
(hatch) within the drawing outline creates an illusion <strong>of</strong><br />
depth. Another aid to realism in black-and-white drawings<br />
is to show foreground structures as darker and<br />
larger than background ones. Obvious examples using<br />
this technique are the pitcher-plant leaves (see 91)<br />
and the iris flower and leaves (see 129). We see color<strong>ed</strong><br />
objects as brighter and more distinct when near<br />
and as mut<strong>ed</strong> and less distinct when distant. Accordingly,<br />
by the use <strong>of</strong> bright shades <strong>of</strong> colors for foreground<br />
structures and mut<strong>ed</strong> shades for background<br />
structures, your color<strong>ed</strong> pictures will appear more 3dimensional.<br />
Darker shades <strong>of</strong> a color on the dot-andline<br />
shadow areas will add to the effect.<br />
To avoid having a green book, the illustration <strong>of</strong> foliage<br />
has been kept to a minimum with an abundant variety<br />
<strong>of</strong> colors indicat<strong>ed</strong> throughout. In the introduction to<br />
plants section, there is uniformity <strong>of</strong> a designat<strong>ed</strong> color.<br />
For example, water-conducting tissue and cells (xylem)<br />
are always color-cod<strong>ed</strong> blue, so that as you look at your<br />
color<strong>ed</strong> pages, you see how water moves within a plant.<br />
For enlarg<strong>ed</strong> flower drawings in the flowering plant families<br />
section, true colors <strong>of</strong> flower parts are indicat<strong>ed</strong> in<br />
the Color Code. Dott<strong>ed</strong> lines indicate where structures<br />
have been cut, show “see-through” areas, or separate<br />
color areas. Some lines are close together, others are<br />
single lines to color, but a color overlap <strong>of</strong> the lines will<br />
not detract from the over-all result.<br />
Begin with the first page, which explains the names<br />
us<strong>ed</strong>, then choose any page that strikes your interest.<br />
If a flowering plant structure is new to you, it would be<br />
most helpful to look over the structure <strong>of</strong> the stem (14),<br />
leaf (21, 23), flower (27, 28), and fruit types (38, 39).<br />
Then, you will be ready to explore. Some discoveries<br />
are seeing how an apple flower matures into an apple<br />
(see 99), finding that grape flowers have flip-top petal<br />
caps (see 104), and learning that inside a common garden<br />
sage flower is a mechanical “arm” for sticking pollen<br />
on visiting bees (see 113).<br />
vii
Acknowl<strong>ed</strong>gements<br />
We wish to thank the following colleagues <strong>of</strong> The University<br />
<strong>of</strong> Michigan for their contribution and review <strong>of</strong><br />
specific topics: Dr. Joseph Beitel, lycopods; Dr. Michael<br />
Carleton, bats; Dr. Allen Fife, lichens; Dr. Michael Huft,<br />
euphorbs; Dr. Thomas Rosatti, heaths; Dr. Ann Sakai,<br />
maples; Dr. Alan Simon, birds; Dr. Wm. Wayt Thomas,<br />
s<strong>ed</strong>ges; Dr. Kerry S. Walter, orchids. Also, we would<br />
like to thank the following University <strong>of</strong> Michigan <strong>Botany</strong><br />
Faculty in the Department <strong>of</strong> <strong>Botany</strong> (now, Department<br />
<strong>of</strong> Ecology and Evolutionary Biology and Department<br />
<strong>of</strong> Molecular, Cellular, and Developmental Biology);<br />
Dr. Howard Crum, bryophytes; Dr. Harry Douthit,<br />
bacteria; Dr. Robert Shaffer, fungi; Dr. William R. Taylor,<br />
algae; Dr. Edward G. Voss, grasses; and Dr. Warren H.<br />
Wagner, Jr., ferns, plus access to his extensive plant<br />
collections; the staffs <strong>of</strong> the University Herbarium, Museum<br />
<strong>of</strong> Natural History and University Science Library<br />
for advice, loans <strong>of</strong> resource materials, use <strong>of</strong><br />
microscopes, books and other print<strong>ed</strong> materials. Dr. P.<br />
Dayananadan was especially generous with his excellent<br />
scanning electron micrographs. For assistance in<br />
obtaining rare and out-<strong>of</strong>-season living plants, we thank<br />
William Collins, Jane LaRue, and Patricia Pachuta <strong>of</strong><br />
the University <strong>of</strong> Michigan Matthaei Botanical Gardens.<br />
We also thank Dr. David Darby <strong>of</strong> the University <strong>of</strong><br />
Minnesota for his review <strong>of</strong> geological information. For<br />
palms, we thank Dr. Ackerman <strong>of</strong> the Garfield Conservatory,<br />
Chicago. For locating regional plants, we appreciate<br />
the assistance <strong>of</strong> Robert Anderson, Patricia and<br />
Terrance Glimn, Marie Mack, Lorraine Peppin, Ellen<br />
Weatherbee, and Catherine Webley. Also, we wish to<br />
thank Dr. Peter Carson, Dr. Tomas Carlson, Dr. Michael<br />
Christianson, Dr. Michael Evans, Dr. Jack Fisher, and<br />
Dr. James Wells.<br />
For reviewing the text format and page design, reading<br />
and coloring sample pages, and suggesting many<br />
helpful changes, we thank the 80 beginning biology<br />
students <strong>of</strong> James Lenic and James Potoczak <strong>of</strong> the<br />
West High School, Garden City, Michigan, 1980, and<br />
the 93 practical botany students <strong>of</strong> Dr. Eric Steiner, Dr.<br />
Kit Streusand, Dr. Lucinda Thompson, Dr. Gay Troth,<br />
and Dr. James Winsor <strong>of</strong> the University <strong>of</strong> Michigan.<br />
From the School <strong>of</strong> Art and Design at The University<br />
<strong>of</strong> Michigan, we are indebt<strong>ed</strong> to Douglas Hesseltine for<br />
book design suggestions, to Duane Overmyer for typography<br />
lessons, and William L. Brudon as both instructor<br />
<strong>of</strong> biological illustration and as an advisor and friend.<br />
Belat<strong>ed</strong>ly, we wish to gratefully thank our <strong>ed</strong>itor at Van<br />
Nostrand & Reinhold, Susan Munger, for the first <strong>ed</strong>ition.<br />
Now with the publication <strong>of</strong> the second <strong>ed</strong>ition, we<br />
wish to wholeheart<strong>ed</strong>ly thank our <strong>ed</strong>itors Jacco Flipsen,<br />
Keri Witman, and Shoshana Sternlicht at Springer. Also,<br />
many thanks to Robert Mag<strong>ed</strong> and his Springer production<br />
staff.<br />
Lastly, we express our special appreciation to our<br />
families—Jack, John, and Jim <strong>Lacy</strong> and Hazel, Linda,<br />
and Laura Kaufman.<br />
ix
Contents<br />
v Preface<br />
vii Color Code Clues<br />
ix Acknowl<strong>ed</strong>gements<br />
Introduction to Plants<br />
1 Names and Terms<br />
2 Cell Structure<br />
3 Cell Organelles<br />
4 Cell Pigments<br />
5 Cell—Water Movement<br />
6 Cell Chromosomes<br />
7 Cell—Mitosis<br />
8 Cell Types<br />
9 Tissue Systems <strong>of</strong> the Plant Body<br />
10 Tissue—Epidermis<br />
11 Tissue—Primary Vascular System<br />
12 Root Types and Modifications<br />
13 Root Tissues<br />
14 Stem Structure<br />
15 Stem Tissues<br />
16 Stem Modifications<br />
17 Stem—Water Transport<br />
18 Stem—Food Transport<br />
19 Stem—Apical Dominance<br />
20 Stem—Growth Movements<br />
21 Leaf Types and Arrangement<br />
22 Leaf Tissues<br />
23 Leaf Modifications<br />
24 Leaf—Photosynthesis<br />
25 Leaf—Nutrient Deficiency Symptoms<br />
26 Flower Initiation in Response to Daylength<br />
27 Flower Structure<br />
28 Flower Structure Variations<br />
29 Flower Development<br />
30 Flower—Meiosis<br />
31 Flower—Pollen Development<br />
32 Flower—Ovule Development<br />
33 Flower Pollination by Insects<br />
34 Flower Pollination by Insects (continu<strong>ed</strong>)<br />
xi
35 Flower Pollination by Wind<br />
36 Flower Pollination by Birds and Bats<br />
37 Flower—Fertilization and Embryo Development<br />
38 Fruit—Dry Types<br />
39 Fruit—Fleshy Types, Compound<br />
40 Se<strong>ed</strong> Structure and Germination<br />
Major Groups<br />
41 Major Groups; Geologic Time Scale<br />
42 Fossils<br />
43 Fossils (continu<strong>ed</strong>)<br />
44 Blue-greens<br />
45 Slime Molds<br />
46 Water Molds, Downy Mildews, White Rusts; Chytrids and Allies<br />
47 Fungi<br />
48 Molds, Mildews, Morels (Sac Fungi)<br />
49 Rusts, Smuts, Jelly Fungi (Club Fungi)<br />
50 Gill Fungi<br />
51 Gill and Pore Fungi<br />
52 Pore, Coral and Tooth<strong>ed</strong> Fungi<br />
53 Puffballs, Stinkhorns, Bird’s-nest Fungi<br />
54 Lichens<br />
55 Din<strong>of</strong>lagellates<br />
56 Golden Algae, Yellow-green Algae, Diatoms<br />
57 R<strong>ed</strong> Algae<br />
58 Green Algae<br />
59 Brown Algae<br />
60 Brown Algae (continu<strong>ed</strong>)<br />
61 Brown Algae (continu<strong>ed</strong>)<br />
62 Stoneworts<br />
63 Liverworts, Hornworts, Mosses<br />
64 Whisk Ferns<br />
65 Clubmosses, Spikemosses, Quillworts<br />
66 Horsetails<br />
67 Ferns<br />
68 Common Ferns<br />
69 Fern Leaf Development<br />
70 Water Ferns<br />
71 Cycads<br />
72 Ginkgo<br />
73 Conifers<br />
74 Gnetes<br />
xii
75 Flowering Plant Classification<br />
76 Major Land Plant Communities<br />
Flowering Plant Families<br />
Dicotyl<strong>ed</strong>ons<br />
77 Magnolia Family (Magnoliaceae)<br />
78 Laurel Family (Lauraceae)<br />
79 Water Lily Family (Nymphaeaceae)<br />
80 Buttercup Family (Ranunculaceae)<br />
81 Witch Hazel Family (Hamamelidaceae)<br />
82 Elm Family (Ulmaceae)<br />
83 Beech Family (Fagaceae)<br />
84 Birch Family (Betulaceae)<br />
85 Cactus Family (Cactaceae)<br />
86 Cactus Family (continu<strong>ed</strong>)<br />
87 Pink Family (Caryophyllaceae)<br />
88 Goosefoot Family (Chenopodiaceae)<br />
89 Buckwheat Family (Polygonaceae)<br />
90 Mallow Family (Malvaceae)<br />
91 Pitcher-Plant Family (Sarraceniaceae)<br />
92 Violet Family (Violaceae)<br />
93 Begonia Family (Begoniaceae)<br />
94 Gourd Family (Cucurbitaceae)<br />
95 Willow Family (Salicaceae)<br />
96 Mustard Family (Brassicaceae)<br />
97 Heath Family (Ericaceae)<br />
98 Saxifrage Family (Saxifragaceae)<br />
99 Rose Family (Rosaceae)<br />
100 Pea Family (Fabaceae)<br />
101 Dogwood Family (Cornaceae)<br />
102 Staff-tree Family (Celastraceae)<br />
103 Spurge Family (Euphorbiaceae)<br />
104 Grape Family (Vitaceae)<br />
105 Maple Family (Aceraceae)<br />
106 Cashew Family (Anacardiaceae)<br />
107 Rue Family (Rutaceae)<br />
108 Geranium Family (Geraniaceae)<br />
109 Carrot Family (Apiaceae)<br />
110 Milkwe<strong>ed</strong> Family (Asclepiadaceae)<br />
111 Nightshade Family (Solanaceae)<br />
112 Morning Glory Family (Convolvulaceae)<br />
113 Mint Family (Lamiaceae)<br />
xiii
114 Olive Family (Oleaceae)<br />
115 Figwort Family (Scrophulariaceae)<br />
116 Gesneria Family (Gesneriaceae)<br />
117 Honeysuckle Family (Caprifoliaceae)<br />
118 Teasel Family (Dipsacaceae)<br />
119 Aster Family (Asteraceae)<br />
Monocotyl<strong>ed</strong>ons<br />
120 Water-plantain Family (Alismataceae)<br />
121 Spiderwort Family (Commelinaceae)<br />
122 S<strong>ed</strong>ge Family (Cyperaceae)<br />
123 Grass Family (Poaceae)<br />
124 Arrowroot Family (Marantaceae)<br />
125 Palm Family (Arecaceae)<br />
126 Palm Family (continu<strong>ed</strong>)<br />
127 Arum Family (Araceae)<br />
128 Lily Family (Liliaceae)<br />
129 Iris Family (Iridaceae)<br />
130 Orchid Family (Orchidaceae)<br />
131 Bibliography<br />
133 Glossary <strong>of</strong> Word Roots, Metric Equivalents<br />
135 <strong>Index</strong><br />
xiv
About the Authors<br />
Janice Glimn-<strong>Lacy</strong> has a Bachelor <strong>of</strong> Science in <strong>Botany</strong> from The University <strong>of</strong> Michigan,<br />
1973, and plans to have a Bachelor <strong>of</strong> Fine Arts from Herron School <strong>of</strong> Art and Design, Indiana<br />
University-Purdue University at Indianapolis (IUPUI), 2008. She is a member <strong>of</strong> the University <strong>of</strong><br />
Michigan Alumni Association, the Indiana Native Plant and Wildflower Society, the Indianapolis<br />
Museum <strong>of</strong> Art, the Indianapolis Museum <strong>of</strong> Art Horticultural Society, and the Watercolor Society<br />
<strong>of</strong> Indiana. While a Landscape Designer, she wrote and illustrat<strong>ed</strong> What Flowers When with<br />
Hints on Home Landscaping (the Flower and the Leaf, Indianapolis, 1995). She was a co-author<br />
and illustrator <strong>of</strong> Practical <strong>Botany</strong> (Reston), illustrator <strong>of</strong> Michigan Trees (University <strong>of</strong> Michigan<br />
Press), Plants Their Biology and Importance (Harper & Row), several Ph.D. theses, and many<br />
botanical journal articles. For several years she taught botanical illustration in the University<br />
<strong>of</strong> Michigan Adult Education Program, at the Indianapolis Art Center, and at the Indianapolis<br />
Museum <strong>of</strong> Art.<br />
Peter B. Kaufman, Ph.D. <strong>Botany</strong>, obtain<strong>ed</strong> degrees at Cornell University and the University <strong>of</strong><br />
California, Davis. A plant physiologist, now Pr<strong>of</strong>essor Emeritus <strong>of</strong> Biology, and currently, Senior<br />
Research Scientist in the University <strong>of</strong> Michigan Integrative M<strong>ed</strong>icine Program (MIM), he has<br />
been at the University <strong>of</strong> Michigan since 1956. He is a Fellow <strong>of</strong> the American Association for<br />
the Advancement <strong>of</strong> Science (AAAS). He is past President <strong>of</strong> the Michigan Botanical Club, past<br />
Chairman <strong>of</strong> the Michigan Natural Areas Council, a co-author <strong>of</strong> Practical <strong>Botany</strong> (Reston), Plants,<br />
People and Environment (Macmillan), Plants Their Biology and Importance (Harper & Row),<br />
Creating a Sustainable Future, Living in Harmony With the Earth (Researchco Book Center),<br />
Natural Products from Plants (CRC Press)/Taylor and France’s Group, LLC, Handbook <strong>of</strong> Molecular<br />
and Cellular Methods in Biology and M<strong>ed</strong>icine (CRC Press), Methods in Gene Biotechnology<br />
(CRC Press), and the author <strong>of</strong> numerous articles in botanical journals. He host<strong>ed</strong> a 20-part <strong>ed</strong>ucational<br />
TV series ‘The House Botanist ’ (University <strong>of</strong> Michigan) and twice was a guest on ABC’s<br />
program ‘Good Morning America’ to talk on gardening topics.
Names and Terms<br />
Division. The major category is call<strong>ed</strong> a division<br />
and is equivalent to phylum in the animal kingdom.<br />
Division name endings indicate plants (-phyta) and<br />
fungi (-mycota). In the top illustration are some examples<br />
<strong>of</strong> Magnoliophyta, the flowering plant division. The<br />
endings <strong>of</strong> lesser categories indicate class (-opsida),<br />
subclass (-idea), order (-ales), and family (-aceae).<br />
Classification <strong>of</strong> one specific plant is shown.<br />
Class. Flowering plants are divid<strong>ed</strong> into 2 classes:<br />
Magnoliopsida, the dicots (2 se<strong>ed</strong> leaves), and Liliopsida,<br />
the monocots (1 se<strong>ed</strong> leaf). A se<strong>ed</strong> leaf is the first<br />
leaf to emerge from an embyro in the se<strong>ed</strong> (see 40). In<br />
the second illustration are examples <strong>of</strong> Liliopsida, the<br />
monocot class.<br />
Family. The third group <strong>of</strong> plants shows some monocots<br />
in the lily family, Liliaceae (see 128).<br />
Genus Species. Next are 3 lilies in the genus<br />
Lilium. A plant type is given a 2-part scientific name – a<br />
generic name, the genus, which is a noun and is always<br />
capitaliz<strong>ed</strong>, and a specific epithet, the species, which<br />
is usually an adjective. For example <strong>of</strong>ficinalis means<br />
m<strong>ed</strong>icinal and is commonly us<strong>ed</strong> for herbs. Sometimes<br />
a species is nam<strong>ed</strong> for a person. A species that is not<br />
nam<strong>ed</strong> is written as sp. (plural: spp.).<br />
In a written list <strong>of</strong> species in the same genus, it is<br />
only necessary to fully write the genus once at the beginning.<br />
The genus <strong>of</strong> species that follow is indicat<strong>ed</strong><br />
with the first letter <strong>of</strong> the genus follow<strong>ed</strong> by a period.<br />
For example: Mammillaria albescens, M. bocasana,<br />
M. columbiana.<br />
The 2 parts <strong>of</strong> the name, call<strong>ed</strong> a binomial, are italiciz<strong>ed</strong><br />
in print and underlin<strong>ed</strong> when handwritten. The<br />
binomial is sometimes follow<strong>ed</strong> by a name abbreviation<br />
<strong>of</strong> the person who first describ<strong>ed</strong> the plant in botanical<br />
literature. For example, the most common is Linnaeus,<br />
the Sw<strong>ed</strong>ish botanist, indicat<strong>ed</strong> by an L.<br />
One <strong>of</strong> the reasons the scientific name <strong>of</strong> a plant may<br />
change is because it is discover<strong>ed</strong> that someone else<br />
nam<strong>ed</strong> the plant earlier. The newly found name is publish<strong>ed</strong><br />
in Latin. Another reason a name may change<br />
is that the plant is reclassifi<strong>ed</strong> into a different group.<br />
There may also be many forms <strong>of</strong> a plant with separate<br />
species names, when later, it is decid<strong>ed</strong> they are all the<br />
same species.<br />
1<br />
The specific lily here is Lilium michiganense, with the<br />
English common name Michigan Lily. A spontaneously<br />
occurring variation <strong>of</strong> a species in nature also may have<br />
a variety (var.) name (see 101). An X between the<br />
genus and new specific epithet (see 77) indicates a hybrid<br />
between 2 species. Hybrids may occur in nature or<br />
be deriv<strong>ed</strong> by plant bre<strong>ed</strong>ing. Intergeneric hybrids have<br />
a combin<strong>ed</strong> name <strong>of</strong> the genera with a capital X at the<br />
beginning. For example, X Heucherella is a hybrid between<br />
Herchera (pink to r<strong>ed</strong> flowers) and Tiarella (white<br />
flowers) and has pale pink flowers.<br />
Common Names. As names differ from region to region,<br />
a plant may have many common names. For<br />
example, Amelanchier may be commonly nam<strong>ed</strong> serviceberry,<br />
shadbush, or June-berry. Sometimes a common<br />
name is us<strong>ed</strong> for unrelat<strong>ed</strong> plants. So to be universally<br />
understood, botanists use the binomial system <strong>of</strong><br />
naming plants in Latin. A plant variety that exists only<br />
through cultivation has a common cultivar name (cv.,<br />
cultivat<strong>ed</strong> variety) (see 93).<br />
Habit vs. Habitat. The gross habit refers to the appearance<br />
<strong>of</strong> an individual plant in its entirety. Where<br />
a plant grows in its environment is call<strong>ed</strong> the habitat,<br />
such as a beech-maple forest, a pond, a prairie, or a<br />
desert.<br />
Herbaceous vs. Woody. Herbs have little or no secondary<br />
vascular tissues and their above-ground shoots<br />
usually die back at the end <strong>of</strong> the growing season. Herbs<br />
are consider<strong>ed</strong> to be more advanc<strong>ed</strong> in evolution than<br />
woody plants (shrubs and trees) with secondary vascular<br />
tissues (secondary xylem and phloem) present,<br />
which persists in growth year after year in stems and<br />
roots.<br />
Macroscopic vs. Microscopic. If a plant structure can<br />
be seen with the unaid<strong>ed</strong> eye, it is designat<strong>ed</strong> macroscopic;<br />
if a microscope is us<strong>ed</strong> to observe it, it is microscopic<br />
in size.<br />
COLOR CODE<br />
orange: tepals (a) (see 27)<br />
brown: stamens (b)<br />
light green: stigma (c)<br />
green: p<strong>ed</strong>uncle (d), leaves (e), stem (f)
Cell Structure<br />
Parts <strong>of</strong> a Cell<br />
Cell Wall. The cell wall (a) encloses and protects the<br />
cell contents and plays a vital role in cell division and<br />
cell expansion. Compos<strong>ed</strong> <strong>of</strong> overlapping cellulose micr<strong>of</strong>ibrils,<br />
other polysaccharides and varying amounts<br />
<strong>of</strong> lignin, the cell wall is a relatively rigid structure in mature<br />
cells. It may vary in thickness and has pits that that<br />
function in communication between cells. The region<br />
between the primary walls <strong>of</strong> adjacent cells, the middle<br />
lamella (b), is compos<strong>ed</strong> <strong>of</strong> a cementing substance<br />
call<strong>ed</strong> pectin.<br />
Other substances that may be present in the cell wall<br />
are gums, resins, silica, calcium carbonate, waxes and<br />
cutin, and both structural protein and enzymes (which<br />
are also proteins). There may be intercellular spaces<br />
(c) between walls <strong>of</strong> bordering cells.<br />
Pits. Primary pit fields (d) are thin areas in the cell wall<br />
with tiny strands <strong>of</strong> cytoplasm, call<strong>ed</strong> plasmodesmata<br />
(s), connecting one cell with another. Pits are important<br />
in facilitating the flow <strong>of</strong> water and mineral nutrients between<br />
conducting cells in the xylem vascular tissue (see<br />
11).<br />
Plasma Membrane. A semipermeable membrane (e)<br />
encloses the cytoplasm within a cell. It is compos<strong>ed</strong><br />
<strong>of</strong> variable amounts <strong>of</strong> fat type molecules (lipids) and<br />
proteins, and has within it channels for the movement<br />
<strong>of</strong> ions such as potassium (K + ), calcium (Ca 2 + ), and<br />
hydrogen (H + ).<br />
Cytoplasm. The cytoplasm (cytosol, f) is a liquid, gellike<br />
substance and contains several types <strong>of</strong> organelles;<br />
smooth (g) or rough endoplasmic reticulum (h), rough<br />
referring to attach<strong>ed</strong> ribosomes (i) on the ER (endoplasmic<br />
reticulum) and free ribosomes.<br />
Vacuole. In a mature plant cell, one large vacuole usually<br />
occupies most <strong>of</strong> the space within the cell. It is sur-<br />
2<br />
round<strong>ed</strong> by a single-layer<strong>ed</strong> membrane, the tonoplast<br />
(j), and contains cell sap compos<strong>ed</strong> <strong>of</strong> water, sugars,<br />
and various organic and inorganic solutes. It may, in<br />
some cells such as in beet roots and flower petals, contain<br />
water-soluble pigments. The vacuole functions in<br />
regulation <strong>of</strong> osmotic balance and turgidity <strong>of</strong> the cell,<br />
and it stores secondary metabolites.<br />
Organelles. Within the cytoplasm are mitochrondria<br />
(k), dictyosomes (Golgi bodies), microbodies, and microtubules<br />
(m). Microtubules are represent<strong>ed</strong> by an array<br />
<strong>of</strong> parallel tubular tracks and facilitate movement <strong>of</strong><br />
proteins and organelles within the cell. The ER is a system<br />
<strong>of</strong> tubes and sacs, that work with dictyosomes to<br />
produce and secrete compounds and deliver specific<br />
proteins and membrane lipids to their proper locations<br />
within a cell.<br />
Also, there may be plastids such as chloroplasts (n), leucoplasts,<br />
and chromoplasts; and non-living substances<br />
<strong>of</strong> water-soluble products or reserve substances such<br />
as oil droplets, protein bodies, and crystals (see 3).<br />
Nucleus. The nucleus is enclos<strong>ed</strong> by a double membrane<br />
(o) that has pores (p) in it to allow communication<br />
with the cytoplasm (f). Within the nucleus are chromosomes,<br />
which contain DNA ne<strong>ed</strong><strong>ed</strong> to create proteins<br />
within the cell. Chromosomes are only visible during cell<br />
division (see 6 and 7). Also present in the nucleus are<br />
one or more nucleoli (q) containing RNA. The rest <strong>of</strong> the<br />
nucleus is fill<strong>ed</strong> with nucleoplasm (r). The information<br />
ne<strong>ed</strong><strong>ed</strong> to create the entire plant is within the nucleus,<br />
mitochondria, and chloroplasts <strong>of</strong> each cell.<br />
COLOR CODE<br />
tan: cell wall (a), middle lamella (b),<br />
dictyosome (l)<br />
colorless: intercellular space (c), pit field (d),<br />
plasma membrane (e), vacuolar<br />
membrane (j)<br />
purple: smooth ER (g), rough ER (h)<br />
black: ribosome (i)<br />
green: chloroplast (n)<br />
blue: mitochondrion (k)<br />
orange: mitrotubules (m)<br />
r<strong>ed</strong>: nuclear membrane (o), pore (p)<br />
gray: nucleolus (q)<br />
pink: nucleoplasm (r)<br />
yellow: cytoplasm (f), plasmodesmata (s)
Cell Organelles<br />
The cytoplasm (cytosol) <strong>of</strong> a plant cell contains various<br />
organelles with specific functions. With the use<br />
<strong>of</strong> a transmission electron microscope (TEM), which<br />
shows structures magnifi<strong>ed</strong> thousands <strong>of</strong> times, these<br />
organelles can be view<strong>ed</strong> individually. The organelles<br />
represent<strong>ed</strong> here are not shown in proportion to one<br />
another.<br />
Plastids. Plastids are classifi<strong>ed</strong> by the primary pigment<br />
they contain. Young cells have undifferentiat<strong>ed</strong><br />
plastids (proplastids), which can multiply by simple division.<br />
They develop into the various kinds <strong>of</strong> plastids<br />
characteristic <strong>of</strong> mature cells.<br />
Chloroplast. This plastid (a) is where photosynthesis<br />
takes place. In higher plants it is usually oval-shap<strong>ed</strong><br />
and is surround<strong>ed</strong> by a double membrane (b). Within<br />
it are sac-like structures (shown cut in half) call<strong>ed</strong> thylakoids<br />
(c). A stack <strong>of</strong> thylakoids is call<strong>ed</strong> a granum (d),<br />
and this is where green chlorophyll pigments are locat<strong>ed</strong>.<br />
Chlorophyll and proteins bound to the thylakoids<br />
use light energy to make simple sugars from carbon<br />
dioxide and water (photosynthesis, see 24).<br />
Extensions from some thylakoid membranes form interconnections<br />
between grana. The thylakoids also<br />
contain accessory pigments, carotenoids, and xanthophylls.<br />
In the stroma (e) <strong>of</strong> the chloroplast are DNA,<br />
RNA, oil droplets (f), ribosomes (g), and other materials<br />
such as starch grains, found in chloroplasts <strong>of</strong> green<br />
plant tissues that have been actively photosynthesizing.<br />
Leucoplast. Such colorless plastids contain storage<br />
products, which include oils, protein bodies, or starch<br />
3<br />
grains. In plant parts with a high starch content, such as<br />
potato tubers or rice grains, a leucoplast that contains<br />
starch grains (h) is call<strong>ed</strong> an amyloplast (i).<br />
Chromoplast. These plastids are color<strong>ed</strong> r<strong>ed</strong> (k), orange<br />
(l), or yellow (m), depending on the pigments they<br />
contain. In the changing colors <strong>of</strong> ripening fruit such<br />
as a tomato or a r<strong>ed</strong> pepper, the chloroplasts (green)<br />
differentiate into chromoplasts (orange to r<strong>ed</strong>). As fruit<br />
color changes, so do plastid structure, pigment types,<br />
and content.<br />
Mitochondria. These organelles are surround<strong>ed</strong> by a<br />
double membrane (n). The inner <strong>of</strong> these two membranes<br />
(o) has infoldings, call<strong>ed</strong> cristae (p), that protrude<br />
into the cavity within. Mitochondria are the primary<br />
sites <strong>of</strong> enzymes controlling cell respiration (a chemical<br />
release <strong>of</strong> energy from sugar or other metabolites).<br />
They can replicate by simple division and, like chloroplasts,<br />
they contain DNA.<br />
Ribosomes. Ribosomes (q) contain ribosomal RNA<br />
and function in protein synthesis. They are also found in<br />
cytoplasm, and associat<strong>ed</strong> with the endoplasmic reticulum<br />
(r) in the cytoplasm.<br />
Dictyosomes (Golgi Bodies). These organelles appear<br />
as a stack <strong>of</strong> flatten<strong>ed</strong> sacs (s) and associat<strong>ed</strong><br />
vesicles (t). Dictyosomes produce and secrete cell wall<br />
polysaccharide precursors and complex carbohydrate<br />
substances that are secret<strong>ed</strong> out <strong>of</strong> root cap cells. This<br />
results in less injury to the growing root as it penetrates<br />
the soil.<br />
COLOR CODE<br />
green: chloroplast (a), thylakoid (c), granum (d)<br />
white: double membrane (b, n), stroma (e),<br />
starch grain (h), amyloplast (i)<br />
yellow: lipid (f), chromoplast (m)<br />
black: ribosome (g, q)<br />
blue: inner membrane (o), crista (p)<br />
r<strong>ed</strong>: chromoplast (k)<br />
orange: chromoplast (l)<br />
purple: endoplasmic reticulum (r)<br />
tan: dictyosome sacs (s), vesicles (t)
Cell Pigments<br />
Chlorophylls. The chlorophylls are oil-soluble. Chlorophyll<br />
a (greenish-yellow in solution) is the primary<br />
photosynthetic pigment in green plants for the transfer<br />
<strong>of</strong> light energy to a chemical acceptor. Light that is<br />
absorb<strong>ed</strong> provides the energy for photosynthesis (see<br />
24). A green leaf absorbs blue light (mostly at 430<br />
nm) and r<strong>ed</strong> light (mostly at 660 nm). It reflects the<br />
green wavelengths so as to appear green to us. Chlorophyll<br />
a, alone, is found in blue-greens and in some r<strong>ed</strong><br />
algae. Accessory pigments in photosynthesis transfer<br />
light energy to chorophyll a. One <strong>of</strong> these is chlorophyll<br />
b (blue-green solution), found in higher plants<br />
and green algae with chlorophyll a. Chlorophyll c<br />
is also an accessory pigment found with chlorophyll a<br />
in brown algae and diatoms. Chlorophyll d, together<br />
with chlorphyll a, is found in some r<strong>ed</strong> algae.<br />
Carotenoids. These pigments are consider<strong>ed</strong> as accessory<br />
pigments in photosynthesis, when found in<br />
chloroplasts associat<strong>ed</strong> with chlorophyll, and as color<br />
pigments when found in chromoplasts. Carotenoids,<br />
like the chlorophylls, are not water-soluble. They absorb<br />
mainly violet and blue light between 400 and 500<br />
nm, and they reflect r<strong>ed</strong>, orange, yellow, brown, and<br />
the green color <strong>of</strong> avocado fruit. They give color to<br />
carrot roots, tomato fruit, and many yellow flowers.<br />
Carotenoids <strong>of</strong> r<strong>ed</strong> and yellow are reveal<strong>ed</strong> in autumn<br />
leaves (h, I) after the green chlorophyll pigments begin<br />
to break down. This occurs when daylengths start to<br />
shorten and cooler temperatures prevail in temperate<br />
regions <strong>of</strong> the world. Carotenes (yellow or orange nonoxygen<br />
containing pigments) seem to function in the<br />
prevention <strong>of</strong> chlorophyll destruction in the presence<br />
<strong>of</strong> light and oxygen. β-carotene is the most important<br />
<strong>of</strong> the carotines. Xanthophyll pigments are oxygencontaining<br />
carotenoids. They transfer energy to chlorophyll<br />
from light. Some <strong>of</strong> the xanthophylls include lutein,<br />
zeaxanthin, violxanthin, and fucoxanthin, which is found<br />
in brown algae.<br />
Phycobilins. These pigments are water-soluble. As<br />
accessory pigments they absorb light and transfer excitation<br />
energy to chlorophyll a. The r<strong>ed</strong> pigment, phycoerythrin,<br />
is found in r<strong>ed</strong> algae. The blue pigment,<br />
4<br />
phycocyanin, is present in blue-greens and some r<strong>ed</strong><br />
algae.<br />
Phytochrome. This pigment plays an important role in<br />
regulating many processes <strong>of</strong> plant growth and development.<br />
Phytochrome is found in two reversible forms.<br />
One form, Pr, absorbs r<strong>ed</strong> light (mostly at 660 nm) and<br />
reflects a blue-green color. The other form, Pfr, absorbs<br />
far-r<strong>ed</strong> light (mostly at 730 nm) and reflects a light-green<br />
color. The highest amounts <strong>of</strong> phytochrome are found<br />
in meristermatic tissues (see 9).<br />
Flavinoids. These water-soluble pigments accumulate<br />
in cell vacuoles. They absorb ultraviolet wavelengths<br />
<strong>of</strong> light. Anthocyanins are phenolic pigments<br />
that are found in most fruits and in many flowers. These<br />
r<strong>ed</strong>-, purple-, and blue-reflecting pigments are seen<br />
in the r<strong>ed</strong> color <strong>of</strong> apple (Malus) fruit and geranium<br />
(Pelargonium) flowers; the blue <strong>of</strong> cornflowers (Centaurea)<br />
and larkspur (Delphinium); and the r<strong>ed</strong> and purple<br />
<strong>of</strong> Fuchsia (l, m) flowers. The function <strong>of</strong> these pigments<br />
can only be hypothesiz<strong>ed</strong>, but study <strong>of</strong> plants having<br />
these pigments is useful in determining evolutionary<br />
relationships. Flavins <strong>of</strong>ten appear to us as yellow or<br />
ivory-color<strong>ed</strong> flowers. Some flavins, such a rib<strong>of</strong>lavin<br />
(vitamin B2), act as co-factors in enzyme reactions and<br />
some are thought to be receptor pigments in the bending<br />
<strong>of</strong> plants toward light (phototropic responses; see<br />
20).<br />
Betalains. These are water-soluble, nitrogen-containing<br />
r<strong>ed</strong>dish pigments that are found in only 9 families<br />
<strong>of</strong> the flowering plant subclass, Carophyllidae (see 75).<br />
These pigments are water-soluble and found in the vacuoles<br />
<strong>of</strong> cells. Betacyanin appears as blue-violet to r<strong>ed</strong><br />
and is found in beet (Beta) roots (n) and r<strong>ed</strong> cactus flowers.<br />
Betaxanthin pigments reflect yellow, orange, and<br />
orange-r<strong>ed</strong>.<br />
COLOR CODE<br />
purple: column a, petal anthocyanin (l)<br />
blue: column b<br />
green: column c, leaf chlorophylls (g),<br />
ovary (j), p<strong>ed</strong>uncle (k)<br />
yellow: column d, leaf carotenoids (i)<br />
orange: column e<br />
r<strong>ed</strong>: column f, leaf carotenoids (h), sepal<br />
anthocyanin (m)<br />
blue-purple-r<strong>ed</strong>: root betacyanin (n)
Cell—Water Movement<br />
More than 90% <strong>of</strong> most plant tissues is compos<strong>ed</strong> <strong>of</strong><br />
water. Water is ne<strong>ed</strong><strong>ed</strong> for most life processes to take<br />
place. The movement <strong>of</strong> water (a) from cell vacuole (b)<br />
to another cell’s vacuole (c) within the plant is by diffusion<br />
through the cell’s semipermeable plasma membrane<br />
(d), which encloses the cytoplasm (e). The flow is<br />
from a region <strong>of</strong> high concentration <strong>of</strong> water to a region<br />
<strong>of</strong> low concentration <strong>of</strong> water, a process that is call<strong>ed</strong><br />
osmosis. The more substances (solutes) dissolv<strong>ed</strong> in<br />
the water, the lower the concentration (water potential)<br />
<strong>of</strong> water. For example, in a leaf cell that is producing<br />
sugar (a solute, f) from photosynthesis, water passes<br />
into the cell. An osmotic equilibrium is reach<strong>ed</strong> when<br />
water no longer enters the cell.<br />
Turgor Pressure<br />
As water (a) passes into a cell, it expands the plasma<br />
membrane (d), exerting pressure against the cell wall<br />
(g). This is call<strong>ed</strong> turgor pressure. In fully inflat<strong>ed</strong> cells,<br />
turgor pressure is one <strong>of</strong> the key “driving forces” in plant<br />
growth. In cells <strong>of</strong> developing fruits, turgor pressure is<br />
very important for fruit enlargement, and indicates the<br />
necessity <strong>of</strong> keeping plants well water<strong>ed</strong> during this period.<br />
Turgor pressure maintains the size and shape <strong>of</strong><br />
plant parts such as leaves and flowers.<br />
5<br />
Plasmolysis<br />
Water (a) is lost from a cell when there is a lower water<br />
concentration in adjacent cells that have more solutes<br />
present. Turgor pressure within the cell then decreases.<br />
When there is no turgor pressure, the plasma membrane<br />
(d) shrinks from the cell wall (g), leaving through<br />
the cell wall. This process is term<strong>ed</strong> plasmolysis and is<br />
reversible when water is return<strong>ed</strong> to the cytoplasm and<br />
vacuole through osmosis. Plasmolysis <strong>of</strong> cells results in<br />
wilting <strong>of</strong> plant shoots and is the opposite <strong>of</strong> fully turgid<br />
cells, where plants are fully “inflat<strong>ed</strong>” or crisp, like fresh<br />
celery.<br />
“Wilting”<br />
When excessive cell water (a) is lost through evaporation<br />
to surrounding dry air, “wilting” occurs. In this condition<br />
cell turgor pressure is lost, the plasma membrane<br />
(d) shrinks from the cell wall, and cell wall (g) contracts<br />
because there is no external solution to fill in between.<br />
This condition can result in plants that are “permanently<br />
wilt<strong>ed</strong>” if the wilting persists over a period <strong>of</strong> 10 to 12<br />
days. If wilt<strong>ed</strong> plants are water<strong>ed</strong> before they reach the<br />
permanent wilting condition, they regain turgor in several<br />
hours time.<br />
COLOR CODE<br />
dark blue: water (a)<br />
colorless: vacuole membrane (b, c), plasma<br />
membrane (d)<br />
yellow: cytoplasm (e)<br />
light blue: sugar solution (f)<br />
tan: cell wall (g)<br />
r<strong>ed</strong>: nucleus (h)<br />
gray: external solution (i)
Cell Chromosomes<br />
Chromosomes (a) are the darkly stain<strong>ed</strong> microscopic<br />
bodies in the nucleus which contain genetic information<br />
(genes) that determine inheritance characteristics<br />
<strong>of</strong> an organism. A chromosome basically consists <strong>of</strong><br />
a core <strong>of</strong> DNA (deoxyribonucleic acid) surround<strong>ed</strong> by<br />
a jacket <strong>of</strong> basic protein call<strong>ed</strong> histone. Bacteria and<br />
blue-greens have no nuclei or chromosomes, but instead,<br />
have a DNA-bearing structure call<strong>ed</strong> a nucleoid<br />
(see 43). Some <strong>of</strong> their DNA may be in circular forms<br />
call<strong>ed</strong> plasmids (b).<br />
Chromosome Structure. Chromosomes are compos<strong>ed</strong><br />
<strong>of</strong> chromatin, which can be seen microscopically<br />
with the use <strong>of</strong> stains such as the Feulgen reagent or<br />
acetocarmine. Chromosomes are best observ<strong>ed</strong> during<br />
mitotic or meiotic division, when the chromatin is<br />
condens<strong>ed</strong> and chromosomes visible (see 7, 30). Chromosomes<br />
have a simple external structure. A chromosome<br />
(a) has a small body call<strong>ed</strong> a centromere (c)<br />
with “arms” (d) on either side. The part <strong>of</strong> the centrome<br />
where spindle fibers are attach<strong>ed</strong> is call<strong>ed</strong> a kinetochore.<br />
Small segments, almost circular, that occur near<br />
the ends <strong>of</strong> a chromosome are call<strong>ed</strong> satellites (e).<br />
During mitosis and meiosis, the chromosome replicates<br />
into two strands call<strong>ed</strong> chromatids (f) attach<strong>ed</strong> together<br />
at the centromere. Chiasma (crossing-over)<br />
is when chromatids (f) overlap, break, and exchange<br />
segments with other chromatids (g) during meiosis. It<br />
may involve 2, 3 or all 4 chromatids. This can give rise<br />
to genetic variability or mutations.<br />
Chromosome Number. Chromosome number is characteristic<br />
for the majority <strong>of</strong> vegetative (somatic) cells <strong>of</strong><br />
an organism. This is call<strong>ed</strong> the 2n or diploid number.<br />
Organisms whose somatic cells contain multiple sets <strong>of</strong><br />
chromosomes are call<strong>ed</strong> polyploids. These occur as a<br />
result <strong>of</strong> hybridization between sexually compatible parents<br />
with different chromosome numbers. Polyploidy is<br />
widely evident in plants, but is rare in animals.<br />
6<br />
COLOR CODE<br />
purple: chromosomes (a), centromere (c),<br />
“arms” (d), satellite (e), chromatids (f)<br />
blue: plasmid outline (b)<br />
r<strong>ed</strong>: chromatids (g)<br />
green: chromosomes (h)<br />
black: chromosomes (i)
Cell—Mitosis<br />
Mitosis is a process <strong>of</strong> nuclear division in which chromosomes<br />
divide lengthwise, separate, and form 2 identical<br />
nuclei. Mitosis is usually accompani<strong>ed</strong> by cell division,<br />
which involves the formation <strong>of</strong> a new cell wall<br />
between the 2 identical nuclei. In plants, good sites to<br />
observe mitosis are in root tips, shoot apices, and newly<br />
developing leaves. This is done by making thin sections<br />
<strong>of</strong> the tissues, mounting them on slides, staining them<br />
with acetocarmine or Feulgen stains, then observing<br />
the sections with the high power or oil immersion lens<br />
<strong>of</strong> an optical (light) microscope.<br />
The Cell Cycle<br />
The period when the nucleus is between divisions is<br />
call<strong>ed</strong> interphase. During interphase is a period <strong>of</strong><br />
replication <strong>of</strong> cytoplasmic organelles, follow<strong>ed</strong> by a<br />
period when chromosomes (a) are duplicat<strong>ed</strong>, then<br />
a period when spindle fibers (bundles <strong>of</strong> microtubules)<br />
are made. Phases <strong>of</strong> mitosis are prophase,<br />
metaphase, anaphase, and telophase. Interphase<br />
and the 4 phases <strong>of</strong> mitosis constitute the cell cycle.<br />
Phases <strong>of</strong> Mitosis<br />
Prophase. At the first stage <strong>of</strong> mitosis, the chromosomes<br />
(a) become visible as long threads. For clarification<br />
only 3 chromosomes are shown. On each strand<br />
7<br />
is a small body call<strong>ed</strong> a centromere (f). Then the chromosomes<br />
start to shorten and thicken and divide into<br />
2 helical coil<strong>ed</strong> strands call<strong>ed</strong> chromatids (g). DNA is<br />
replicat<strong>ed</strong> half to each chromatid.<br />
Metaphase. In stain<strong>ed</strong> cells on microscope slides, the<br />
nuclear membrane and nucleolus (b) can no longer be<br />
seen during metaphase in vascular plants. Metaphase<br />
is mark<strong>ed</strong> by the appearance <strong>of</strong> the spindle (h). It is at<br />
this time that the chromosomes migrate to the spindle<br />
and the centromeres (f) align in a flat equatorial plane.<br />
The pairs <strong>of</strong> chromatids (g) are held together at the<br />
centromeres (f).<br />
Anaphase. Anaphase is initiat<strong>ed</strong> with division and separation<br />
<strong>of</strong> the centromere, providing each chromatid<br />
with centromere (f). This phase ends with the chromatids,<br />
which are now call<strong>ed</strong> chromosomes, moving<br />
to opposite poles (i) <strong>of</strong> the spindle (h).<br />
Telophase. This phase begins with the chromosomes<br />
(a) completing their movement to the poles. It ends with<br />
the chromosomes once more becoming diffuse, as in<br />
interphase. A new nuclear membrane (c) forms around<br />
each group <strong>of</strong> chromosomes (a) and nucleoli (b) reappear.<br />
During interphase, a new cell wall (e) forms between<br />
the nuclei.<br />
COLOR CODE<br />
purple: chromosomes (a), centromere (f),<br />
chromatid (g)<br />
gray: nucleolus (b)<br />
r<strong>ed</strong>: nuclear membrane (c)<br />
yellow: cytoplasm (d)<br />
tan: cell wall (e)<br />
orange: spindle (h)
Cell Types<br />
Parenchyma Cells<br />
Parenchyma cells (a) make up the major portion <strong>of</strong> the<br />
primary plant body. They are usually thin-wall<strong>ed</strong> and<br />
vary in shape from spherical with many flat surfaces,<br />
to elongat<strong>ed</strong>, lob<strong>ed</strong>, or fold<strong>ed</strong>. As living cells that are<br />
unspecializ<strong>ed</strong> initially, they later differentiate to more<br />
specializ<strong>ed</strong> cells. Parenchyma cells are found in photosynthetic<br />
tissue <strong>of</strong> green leaves and green stems, in<br />
epidermis, below the epidermis in cortex (b), in pith, and<br />
in the vascular system.<br />
As food storage cells, they occur in specializ<strong>ed</strong> organs<br />
such as bulbs and tubers, in se<strong>ed</strong>s (as endosperm), and<br />
in se<strong>ed</strong> leaves (cotyl<strong>ed</strong>ons). Specializ<strong>ed</strong> parenchyma<br />
tissue (also call<strong>ed</strong> aerenchyma) with intercellular air<br />
spaces aids water plants in floating. Parenchyma cells<br />
may appear as secretory forms such as glandular and<br />
stinging hairs, nectaries, and salt glands.<br />
Collenchyma Cells<br />
Collenchyma cells (c) provide elastic support to stems<br />
and leaves due to variously thicken<strong>ed</strong> primary walls (d)<br />
containing cellulose, hemicellulose, pectin, and water.<br />
These closely arrang<strong>ed</strong>, living cells are short or elongat<strong>ed</strong><br />
in shape. They are usually found near the surface<br />
in the cortex around vascular bundles (e) <strong>of</strong> leaf petioles<br />
and stems.<br />
Sclerenchyma Cells<br />
Sclerenchyma tissue cells function in mechanical support<br />
due to thick lignifi<strong>ed</strong> secondary walls (f), which contain<br />
large amounts <strong>of</strong> cellulose and lignin. At maturity,<br />
some sclerenchyma cells no longer have living protoplasts.<br />
Fibers and sclerids are types <strong>of</strong> sclerenchyma<br />
cells.<br />
Fibers (g) are elongat<strong>ed</strong> cells with pitt<strong>ed</strong> cell walls (h).<br />
They are found in water-conducting tissue, xylem (i) and<br />
food-conducting tissue, phloem (j), along leaf veins and<br />
margins, and surrounding vascular bundles in stems.<br />
Examples <strong>of</strong> commercial fibers are hemp, flax, jute, rattan,<br />
and cotton, us<strong>ed</strong> in making rope, mats and baskets.<br />
Sclereids are dense (lignifi<strong>ed</strong>), short cells which may<br />
look like stones, rods, bones, stars, or branch<strong>ed</strong> structures.<br />
Familiar forms, with dense cell layer <strong>of</strong> sclereids<br />
occur in nut shells, fruit pits, and the se<strong>ed</strong> coats in<br />
8<br />
legume tree pods (Fabaceae, see 100). Pear (k) and<br />
quince fruits contain “stone cells” (l), that is, nests <strong>of</strong><br />
sclereids in the fleshy mesocarp (m) tissue (see 39).<br />
Vascular Cells<br />
Cells <strong>of</strong> the xylem tissue, tracheids (n), are elongat<strong>ed</strong>,<br />
have border<strong>ed</strong> wall pits (o) for water conduction, and<br />
are align<strong>ed</strong> side by side. Also, water- and mineralconducting<br />
cells <strong>of</strong> the xylem, namely, the vessel<br />
elements (p), have border<strong>ed</strong> pits (q) in their cell walls.<br />
The vessel elements are align<strong>ed</strong> end-to-end to form<br />
long tubes. The xylem sap passes vertically through<br />
the vessel elements via end perforations that may be<br />
parallel slits (r) or a single large opening (s). Conifers<br />
and primitive woody flowering have only tracheids for<br />
water conduction.<br />
Sieve cells are enucleate (minus a nucleus), found in<br />
the phloem <strong>of</strong> conifers and primitive vascular plants<br />
such as ferns. The sieve cells are elongat<strong>ed</strong> and thinwall<strong>ed</strong>.<br />
Sieve-tube elements (t) are enucleate and<br />
found in more advanc<strong>ed</strong> flowering plants. Both sieve<br />
cells and sieve-tube elements form long end-to-end<br />
columns call<strong>ed</strong> sieve tubes. Sieve plates (u), consisting<br />
<strong>of</strong> primary pit fields, occur in the end walls <strong>of</strong> sieve<br />
tube elements. In sieve cells, the walls, over their surfaces,<br />
contain localiz<strong>ed</strong> sieve areas containing many<br />
pores that allow for cell-to-cell solute transport. Cell-tocell<br />
connecting strands <strong>of</strong> cytoplasm pass through the<br />
sieve plates.<br />
Companion cells (v), a specializ<strong>ed</strong> type <strong>of</strong> parenchyma,<br />
may be present in varying numbers in association<br />
with sieve tube elements.<br />
COLOR CODE<br />
green: parenchyma cells (a), collenchyma cells<br />
(c)<br />
light green: parenchyma cortex (b)<br />
white: vascular bundles (e), xylem (i), phloem<br />
(j), mesocarp (m)<br />
tan: fibers (f, g, h)<br />
yellow: pear epidermis (k), sclereids (l)<br />
blue: tracheid (n, o), vessel elements (p, q, r,<br />
s)<br />
orange: sieve-tube elements (t), sieve plate (u),<br />
companion cells (v)
Tissue Systems <strong>of</strong> the Plant Body<br />
Cells in plants are arrang<strong>ed</strong> in tissues such as epidermis,<br />
cortex, and pith. Several tissues also make up a<br />
tissue system such as the vascular system.<br />
Meristems<br />
Throughout the life <strong>of</strong> a plant, new cells are continuously<br />
being form<strong>ed</strong> at sites call<strong>ed</strong> meristems. Meristems<br />
consist <strong>of</strong> undifferentiat<strong>ed</strong> cells that are found at<br />
shoot tips, at root tips, in the vascular cambium, and in<br />
the cork cambium. Meristems produce cells that differentiate<br />
into specializ<strong>ed</strong> tissues <strong>of</strong> three systems: dermal,<br />
ground, and vascular. Only primary growth (left column),<br />
resulting from the activity <strong>of</strong> the shoot and root<br />
apical meristems, is found in some herbaceous dicots,<br />
most monocots, and lower vascular plants. Conifers and<br />
woody dicot shrubs and trees exhibit secondary growth<br />
(right column).<br />
Shoot Tissue Systems<br />
The shoot is the portion <strong>of</strong> the plant above the roots and<br />
is compos<strong>ed</strong> <strong>of</strong> stems, leaves, flowers and fruits. The<br />
stem apical meristem (a) forms leaf primordia (b) on its<br />
flanks and young stem tissues below during the vegetative<br />
phase, and in flowering plants, flower primordia<br />
during the reproductive phase.<br />
Dermal Tissue System. The outer layer <strong>of</strong> the apical<br />
meristem gives rise to the epidermis (c) <strong>of</strong> the primary<br />
plant body. In the stems <strong>of</strong> plants with secondary<br />
growth, the epidermis is replac<strong>ed</strong> by periderm (d), commonly<br />
call<strong>ed</strong> the “outer bark.” Periderm consists <strong>of</strong> the<br />
meristematic cork cambium producing cork (phellem)<br />
outward and the pelloderm inward (see 15).<br />
Ground Tissue System. The cells and tissues <strong>of</strong> the<br />
ground tissue system are deriv<strong>ed</strong> from the apical meristem.<br />
In the diagram, ground tissue is manifest as cortex<br />
(e), locat<strong>ed</strong> between epidermis and vascular bundles,<br />
and pith (f) in the center <strong>of</strong> the stem.<br />
Vascular Tissue System. Also deriv<strong>ed</strong> from the apical<br />
meristem, the procambium (g) initiates the vascular system<br />
with cells that differentiate inside into primary xylem<br />
(h), the water- and nutrient-conducting tissue, and outside<br />
into primary phloem (i), the food-conducting tissue.<br />
In plants with secondary growth, a persistent cambium,<br />
the vascular cambium (j), makes possible add<strong>ed</strong> layers<br />
9<br />
<strong>of</strong> secondary xylem (k) and phloem (l), resulting in an<br />
increase in stem diameter.<br />
Root Tissue Systems<br />
The root apical meristem (m) produces new root cap<br />
(n) cells ahead (below) <strong>of</strong> the root apex, as well as cells<br />
<strong>of</strong> the protoderm (young epidermis), ground meristem,<br />
and procambium back <strong>of</strong> the root apex.<br />
Dermal Tissue System. With primary growth, roots<br />
are cover<strong>ed</strong> with epidermis (o). With secondary growth,<br />
the epidermis and root hairs (deriv<strong>ed</strong> from epidermal<br />
cells) are slough<strong>ed</strong> <strong>of</strong>f because <strong>of</strong> formation <strong>of</strong> periderm<br />
(p) on the outside.<br />
Ground Tissue System. Cortex (q) lies between the<br />
epidermis and vascular system in portions <strong>of</strong> roots<br />
undergoing primary growth. The innermost layer <strong>of</strong> cortex,<br />
the endodermis (r), bounds the pericycle tissue<br />
(s), which surrounds the primary vascular system. In<br />
portions <strong>of</strong> roots undergoing secondary growth, the cortex,<br />
like the epidermis, is sh<strong>ed</strong> as the periderm develops<br />
cork cells.<br />
Vascular Tissue System. In the root, unlike the stem,<br />
the primary vascular system is in a central cylinder (t)<br />
with xylem and phloem arrang<strong>ed</strong> in an alternate radial<br />
manner. Primary xylem “arms” (u) radiate out from the<br />
center with alternate poles <strong>of</strong> primary phloem (v) in the<br />
outer portion <strong>of</strong> the cylinder. Between them is procambium<br />
(w). In older portions <strong>of</strong> roots, where secondary<br />
growth is evident, the vascular cambium (x) produces<br />
successive layers <strong>of</strong> secondary xylem (y) and phloem<br />
(z).<br />
COLOR CODE<br />
r<strong>ed</strong> dot: apical meristem (a, m)<br />
r<strong>ed</strong> line: procambium (g, w), vascular<br />
cambium (j, x)<br />
colorless: epidermis (c, o), pith (f), root cap (n),<br />
endodermis (r), central cylinder (t)<br />
green: young leaf (b), shoot cortex (e)<br />
blue: primary xylem (h, u)<br />
light blue: secondary xylem (k, y)<br />
orange: primary phloem (i, v)<br />
light orange: secondary phloem (l, z)<br />
tan: root cortex (q), periderm (d, p)<br />
yellow: pericycle (s)
Tissue—Epidermis<br />
Usually a single layer <strong>of</strong> cells (a) makes up the epidermis<br />
that covers roots, stems, leaves, and fruits. At<br />
the outer surface <strong>of</strong> the epidermal cells is a continuous<br />
layer (cuticle, b) made up <strong>of</strong> fatty material (cutin).<br />
It is sometimes overlaid with a protective, waterpro<strong>of</strong><br />
coating <strong>of</strong> wax. Oil, resin, and salt crystals may also be<br />
deposit<strong>ed</strong> on the surface. Functions <strong>of</strong> the epidermis<br />
include mechanical support, protection from desiccation<br />
(drought) and against attack by virulent pathogenic<br />
organisms and insects, gas exchange, restriction <strong>of</strong> water<br />
loss by evaporation (transpiration) through stomates<br />
and water and mineral storage.<br />
In a surface view, the epidermal cells appear hexagonal,<br />
elongat<strong>ed</strong>, or wavy-margin<strong>ed</strong> (c) like jigsaw puzzle<br />
pieces. Shape varies with the plant part being examin<strong>ed</strong>,<br />
such as root, stem, leaf (d), flower parts (e), or<br />
fruit. Some plants such as those in the grass family<br />
(Poaceae), have parallel rows <strong>of</strong> elongat<strong>ed</strong> cells (f) alternating<br />
with short specializ<strong>ed</strong> silica (g) and cork (h)<br />
cells, stomata (i) and trichomes. Pits (j) are present in<br />
the elongat<strong>ed</strong> cells.<br />
Guard Cells. In stomata, pairs <strong>of</strong> guard cells (k), specializ<strong>ed</strong><br />
epidermal cells, control air exchange (CO2 and<br />
O2) and water loss from plants by changing the size <strong>of</strong><br />
the pore (stoma, l) that separates their inner walls. A<br />
pair <strong>of</strong> guard cells can expand or contract as a result<br />
<strong>of</strong> changes in turgor pressure. Usually, as guard cells<br />
develop high turgor pressure, stomata open, and with<br />
r<strong>ed</strong>uc<strong>ed</strong> turgor pressure, they close. The stomatal pore<br />
(l) allows gas exchange to occur between outside air<br />
(m) and inner plant (n) tissues. Other cells, call<strong>ed</strong> subsidiary<br />
cells (o), may be associat<strong>ed</strong> with guard cells.<br />
Trichomes (Hairs). The epidermis may have various<br />
extensions <strong>of</strong> one- or many-cell<strong>ed</strong> hairs (trichomes, r)<br />
some <strong>of</strong> which may be glandular. Glandular excretions<br />
include terpenes (essential oils, carotenoids, saponins,<br />
or rubber), tannins, or crystals (such as salt).<br />
10<br />
Fragrance in flowers is provid<strong>ed</strong> when essential oils in<br />
the petals vaporize. Non-glandular hairs may be found<br />
on any shoot surface as well as on se<strong>ed</strong>s such as cotton<br />
(see 90) and willow (see 95).<br />
Menthol in mints is produc<strong>ed</strong> in hairs on the leaves. It<br />
is the primary flavoring constituent <strong>of</strong> peppermint too.<br />
Many members <strong>of</strong> the mint family (Lamiaceae, see 113)<br />
and aster family (Asteraceae, see 119) produce terpenes<br />
in hairs in leaves and stems that repel herbivores<br />
like deer. The glandular hairs on bracts <strong>of</strong> the female<br />
flowers <strong>of</strong> hops produce humulone that is responsible<br />
for the bitter principle in beer.<br />
The leaves and stems <strong>of</strong> hemp or marijuana (Cannabis<br />
sativa) are cover<strong>ed</strong> with hairs that contain over 20 different<br />
cannabinoids responsible for hallucinogenic properties<br />
<strong>of</strong> this plant. These constituents also help in treating<br />
patients with glaucoma and allaying the adverse side<br />
effects <strong>of</strong> chemotherapy in treating cancer.<br />
Nectar Glands. Nectar glands, found in various flower<br />
structures and on stems and leaves, produce a sugar<br />
solution. Some flowers have specializ<strong>ed</strong> scent glands<br />
(osmophors) in the form <strong>of</strong> flaps, hairs, or brushes.<br />
Glands on the surface <strong>of</strong> carnivorous plants produce<br />
nectar (s) or enzymatic digestive fluids (t).<br />
Root Hairs. Root epidermal cells (u) function in the<br />
uptake <strong>of</strong> water and dissolv<strong>ed</strong> minerals. Most plant<br />
roots produce extensions from the epidermal cells <strong>of</strong><br />
trichomes call<strong>ed</strong> root hairs (v). They occur above the<br />
elongation zone <strong>of</strong> the root. At maturity, root hairs collapse<br />
as the epidermal cells are slough<strong>ed</strong> <strong>of</strong>f. Alternatively,<br />
they may remain intact due to lignification <strong>of</strong> their<br />
cell walls. But even these root hair cells may disappear<br />
as bark forms on the root in more mature regions.<br />
COLOR CODE<br />
colorless: cells (a, c, d, e, f, k, o, t, u), pits (j)<br />
yellow: cuticle (b)<br />
gray: silica cells (g)<br />
tan: cork cell (h)<br />
green: chloroplast (p)<br />
r<strong>ed</strong>: nucleus (q)<br />
optional: trichomes (r, s, v)
Tissue—Primary Vascular System<br />
In the primary plant body, the vascular system is<br />
made up <strong>of</strong> vascular bundles compos<strong>ed</strong> <strong>of</strong> conducting<br />
elements, interspers<strong>ed</strong> with fibers for support and<br />
parenchyma cells for food storage. Procambial cells (a)<br />
give rise to primary xylem toward the inside and primary<br />
phloem toward the outside <strong>of</strong> the plant. In most<br />
monocots, after differentiation <strong>of</strong> vascular elements, no<br />
procambium remains.<br />
Xylem: Water-conducting Tissue<br />
Several types <strong>of</strong> cells (living and non-living) make up<br />
xylem tissue: tracheary elements (b), compos<strong>ed</strong> <strong>of</strong> tracheids<br />
(c) and vessel elements (d), which conduct water<br />
and nutrients; fibers (e), which provide support; and<br />
living parenchyma cells (f), which store food. Sclereids<br />
may also be present. In monocots, vessel elements,<br />
whose walls have been stretch<strong>ed</strong> and broken by elongation,<br />
result in spaces (lacunae, g) in the xylem.<br />
Border<strong>ed</strong> Pits. The primary walls <strong>of</strong> tracheids and vessel<br />
elements have depressions call<strong>ed</strong> primary pit fields.<br />
When secondary walls (h) are form<strong>ed</strong>, the border<strong>ed</strong><br />
holes (pit apertures, i) consist <strong>of</strong> a pit chamber (j) and a<br />
pit membrane (k). Of two adjacent cells, the pits <strong>of</strong> each<br />
are at the same level forming pit-pairs. Compos<strong>ed</strong> <strong>of</strong> the<br />
primary wall <strong>of</strong> each <strong>of</strong> the two adjacent cells, the pit<br />
membrane is permeable and allows passage <strong>of</strong> water<br />
and mineral nutrients from cell to cell.<br />
Phloem: Food-conducting Tissue<br />
Phloem tissue is compos<strong>ed</strong> <strong>of</strong> sieve elements <strong>of</strong> sieve<br />
cells or sieve tube elements (o) for food conduction,<br />
fibers (m), and parenchyma cells (n). Companion<br />
cells (s) are associat<strong>ed</strong> with sieve tube elements.<br />
Latex-producing cells (laticifers) and sclereids may be<br />
present.<br />
(Dicot vascular bundle adapt<strong>ed</strong> with permission: Esau,<br />
K., Plant Anatomy, 1967, John Wiley & Sons.)<br />
11<br />
COLOR CODE<br />
r<strong>ed</strong>: procambial cells (a)<br />
colorless: parenchyma cells (f, n), lacuna (g),<br />
pit membrane (k), secondary wall (h)<br />
blue: tracheary elements (b, c, d)<br />
tan: fibers (e, m)<br />
orange: sieve tube elements (l), companion<br />
cells (o)
Root Types and Modifications<br />
The root is the underground organ <strong>of</strong> the plant. Its primary<br />
functions include uptake <strong>of</strong> water and minerals<br />
and anchorage <strong>of</strong> the above-ground (aerial) portions <strong>of</strong><br />
the plant.<br />
Root Types<br />
In conifers and dicots, a primary root (a), call<strong>ed</strong> a radicle<br />
in the se<strong>ed</strong> embryo, develops lateral branching roots<br />
(b). As this system develops further, the individual roots<br />
may show secondary growth due to cambial activity.<br />
The cambium is a meristem that produces secondary<br />
xylem, and secondary phloem (see 9).<br />
In many monocots, the first-form<strong>ed</strong> roots <strong>of</strong> the<br />
se<strong>ed</strong>ling, call<strong>ed</strong> seminal roots, eventually die. They<br />
are replac<strong>ed</strong> by adventitious roots (d), which emerge<br />
from the stem. Dicots may also have accessory adventitious<br />
roots, for example, the aerial roots on vines such<br />
as ivy (see 16).<br />
Root Modifications<br />
Storage Roots. Plants may develop specializ<strong>ed</strong>, thicken<strong>ed</strong><br />
roots, as those found on carrot (Daucus, f), beet<br />
(Beta), sweet potato (Ipomea batatas, see 112), manroot<br />
(Ipomea pandurata), tuberous begonia (Begonia),<br />
and dahlia (Dahlia). These roots are an adaptation for<br />
food storage and are seen in many biennials and perennials.<br />
A biennial plant is one that produces leaves the<br />
first year and flowers and fruit the second year, then<br />
dies. A perennial plant lives for more than two years.<br />
Prop Roots. Some plants develop supporting roots as<br />
found in corn (Zea, h) and mangrove (Rhizophora).<br />
Such roots are especially effective in anchoring the<br />
shoot system in the soil, preventing them from capsizing<br />
in strong winds, heavy rains, and impact from pr<strong>ed</strong>ators<br />
and human activities.<br />
12<br />
Contractile Roots. Contraction, or shortening <strong>of</strong> some<br />
roots, helps pull down and anchor the plant more firmly<br />
in the soil. Contractile roots (i) are common in herbaceous<br />
dicots and monocots, and occur in taproots, adventitious<br />
roots, and lateral roots, and on roots <strong>of</strong> underground<br />
storage stems such as bulbs and corms. (An<br />
herbaceous plant or herb is nonwoody and can die to<br />
the ground in freezing climates.)<br />
Symbiotic Relationships in Roots<br />
Nodules Involv<strong>ed</strong> in Nitrogen Fixation. Some plants<br />
are stimulat<strong>ed</strong> by certain genera <strong>of</strong> bacteria to develop<br />
extra tissues in the roots in the form <strong>of</strong> nodules (l),<br />
where nitrogen (N2) in the air is “fix<strong>ed</strong>,” that is, convert<strong>ed</strong><br />
to other forms, mainly ammonia (NH3), which<br />
can then be convert<strong>ed</strong> to organic forms such as amino<br />
acids. The bacteria and plant exchange nutrients and<br />
metabolites in a mutually beneficial relationship. Examples<br />
are found in alfalfa (M<strong>ed</strong>icago), clover (Trifolium),<br />
garden pea (Pisum sativum), and garden bean (Phaseolus<br />
vulgaris).<br />
Mycorrhizae. These are mutually beneficial associations<br />
between fungi (n) and plant roots (o). For the plant,<br />
the fungi increase the uptake <strong>of</strong> minerals, particularly<br />
phosphorus, and also water. For the mycorrhizal fungus,<br />
the plant root cells provide sugars, amino acids,<br />
vitamins, and water. Mycorrhizae are classifi<strong>ed</strong> according<br />
to whether the fungal strands (hyphae) invade (endomycorrhizae)<br />
or surround (ectomycorrhizae) the root<br />
cortical cells. A third class is where fungi both invade<br />
and surround (ectendomycorrhizae) root cortical cells.<br />
Most plants have mycorrhizal associations, which help<br />
them compete with other plants. Mycorrhizae develop<br />
best in nutrient-poor soils.<br />
COLOR CODE<br />
tan: dicot root system (a, b), scale leaves (j),<br />
stem axis (k), nodules (l)<br />
green: leaves (c, e, g), prop roots (h)<br />
white: monocot root system (d), roots (i, m, o),<br />
roots swollen with mycorrhizal fungal<br />
strands (n)<br />
orange: storage tap root (f)
Root Tissues<br />
Basic Differentiation Regions <strong>of</strong> the Root<br />
Apical Meristem. The root apical meristem (a) is locat<strong>ed</strong><br />
at root tips. It produces new root cap (b) cells<br />
below, and above, it produces cells that contribute to<br />
protoderm (c), ground meristem <strong>of</strong> the cortex (d), and<br />
procambium (e), the three primary meristems that initiate<br />
tissues.<br />
Root Cap. The function <strong>of</strong> the root cap (b) is to protect<br />
the apical meristem and to aid the developing root as it<br />
penetrates the soil as the root elongates. It is compos<strong>ed</strong><br />
<strong>of</strong> parenchyma cells whose walls, along the surfaces <strong>of</strong><br />
the root cap, are mucilaginous to provide easier passage<br />
through soil particles. As cells (f) are slough<strong>ed</strong><br />
<strong>of</strong>f, more cells are produc<strong>ed</strong> by the apical meristem.<br />
Elongation Region. Back <strong>of</strong> the apical meristem is the<br />
region (g) where most elongation <strong>of</strong> the root takes place.<br />
Mature Root. In primary growth, the epidermal cell<br />
walls <strong>of</strong> the mature root (j) become cutiniz<strong>ed</strong> or suberiz<strong>ed</strong><br />
with wax-like substances. With secondary growth,<br />
the cork cambium replaces epidermis (k) and cortex<br />
with root bark tissues, cork and phelloderm.<br />
Non-vascular Tissue Systems<br />
Epidermis. The epidermis is the outermost tissue <strong>of</strong><br />
the root. It is usually a single layer. In the root elongation<br />
zone are root hairs (h), lateral protrusions <strong>of</strong> epidermal<br />
cells (i), which are active in water and mineral nutrient<br />
uptake.<br />
Cortex. Basically, cortex tissue is made up <strong>of</strong><br />
parenchyma cells. In conifers and dicots with secondary<br />
growth, the cortex (d) is sh<strong>ed</strong>. Monocots, without secondary<br />
growth, retain their cortex and many develop<br />
sclerenchyma tissue. Food, mostly as starch, is stor<strong>ed</strong><br />
in the cortical cells in amyloplasts (see 3). Proplastids<br />
may develop into chloroplasts in cortical cells if the root<br />
is expos<strong>ed</strong> to light.<br />
Endodermis. The innermost layer <strong>of</strong> cortex (d) that encircles<br />
the vascular tissue is call<strong>ed</strong> the endodermis (l).<br />
13<br />
Along the radial and transverse walls <strong>of</strong> endodermal<br />
cells is a suberin-rich fatty layer call<strong>ed</strong> the casparian<br />
strip (m). It blocks absorb<strong>ed</strong> soil water from passing<br />
between the cells to the xylem; thus, water and mineral<br />
nutrients must pass through the selectively permeable<br />
membranes <strong>of</strong> endodermis cells instead, an effective<br />
filtering system (see 17).<br />
Vascular Tissue System<br />
Pericycle. The central cylinder (n) <strong>of</strong> vascular tissue<br />
is surround<strong>ed</strong> by thin-wall<strong>ed</strong> parenchyma tissue call<strong>ed</strong><br />
pericycle (o). The pericycle is the site where vascular<br />
cambium and lateral roots originate. As a lateral root (p)<br />
penetrates through the cortex, its apical meristem and<br />
its derivative tissue systems become organiz<strong>ed</strong>. Adventitious<br />
roots, which develop from stems, are initiat<strong>ed</strong> in<br />
parenchyma near differentiating vascular tissue.<br />
Xylem. If no xylem is form<strong>ed</strong> in the center <strong>of</strong> the root,<br />
parenchyma tissue develops there. Primary xylem arms<br />
(q) radiate from the center and vary in number. The<br />
dicot types include diarch (2 arms), triarch (3 arms), or<br />
tetrarch (4 arms, q), and the monocot type is polyarch<br />
(many arms).<br />
Phloem. Procambium cells (e), between the radiating<br />
arms <strong>of</strong> primary xylem, produce primary phloem (r) outward<br />
and xylem tissue inward. In secondary growth, the<br />
vascular cambium (s), which originates from the pericycle,<br />
extends completely around the tips <strong>of</strong> the xylem<br />
arms and inside the primary phloem poles. It produces<br />
secondary xylem (t) inward and secondary phloem (u)<br />
outward. (For a further stage in secondary growth, see<br />
9, root cross-section.) (Lateral root adapt<strong>ed</strong> with permission:<br />
Esau, K., Plant Anatomy, 1967, John Wiley &<br />
Sons.)<br />
COLOR CODE<br />
r<strong>ed</strong>: apical meristem (a), procambium (e),<br />
vascular cambium (s)<br />
colorless: root cap (b), protoderm (c), root regions<br />
(g, h, i, j), cortex (d), cells (f), epidermis<br />
(k), lateral root (p)<br />
tan: endodermis (l), casparian strip (m)<br />
yellow: pericycle (o)<br />
blue: central cylinder (n), primary xylem (q)<br />
light blue: secondary xylem (t)<br />
orange: phloem (r)<br />
light orange: secondary phloem (u)
Stem Structure<br />
Functions <strong>of</strong> the stem include: photosynthesis; longdistance<br />
transport <strong>of</strong> hormones and organic metabolites<br />
in the phloem; transport <strong>of</strong> water and mineral nutrients<br />
in the xylem; support <strong>of</strong> the shoot system; sites for<br />
responses <strong>of</strong> shoot to gravity (gravitropism) and unilateral<br />
light (phototropism); food storage; and sites <strong>of</strong><br />
initiation <strong>of</strong> adventitious roots, new leaves and inflorescences<br />
(flowers).<br />
Parts <strong>of</strong> a Stem<br />
Shoot Tip. The stem shoot apex produces leaf primordia<br />
(a) that develop into leaves (b).<br />
Node. The site where a leaf or leaves, as well as axillary<br />
buds, arise on the stem is term<strong>ed</strong> a node (c).<br />
Internode. The elongat<strong>ed</strong> portion <strong>of</strong> a stem between<br />
two nodes is call<strong>ed</strong> an internode (d).<br />
Bud. A terminal bud (e), which develops at the apical<br />
end <strong>of</strong> the stem, encloses a meristematic stem axis (f)<br />
with its apical meristem (g). Axillary buds (h) are lateral<br />
buds that form at the leaf-stem axils (nodes) and may<br />
develop into lateral vegetative shoots or flowers.<br />
Bud Scales. Small, modifi<strong>ed</strong> leaves or stipules that<br />
cover and protect the bud are call<strong>ed</strong> bud scales (i).<br />
Some buds lack scale coverings and are call<strong>ed</strong> nak<strong>ed</strong><br />
buds.<br />
Bud Scale Scar. Perennial woody stems exhibit scars<br />
(j) at the sites where terminal bud scales were sh<strong>ed</strong><br />
during previous years (k, l).<br />
Leaf Scar. A scar remains on the stem where a leaf<br />
stalk (petiole) was attach<strong>ed</strong>. Leaf scars (m) and buds<br />
are species-specific, and therefore, are useful for winter<br />
plant identification.<br />
Bundle Scar (Leaf Trace). The vascular bundles (j) from<br />
a sh<strong>ed</strong> leaf appear as dots within a leaf scar.<br />
Lenticel. Openings for gas and water exchange in the<br />
stem surface, call<strong>ed</strong> lenticels (o), are found on some<br />
plants with secondary growth. Lenticels are very prominent,<br />
for example on cherry (Prunus) tree bark.<br />
14<br />
COLOR CODE<br />
r<strong>ed</strong>: apical meristem (g), maple bud scales<br />
(i), procambium (p)<br />
green: leaf primordia (a), leaf (b), node (c),<br />
stem internode (d), bean terminal bud<br />
(e), bean axillary bud (h)<br />
white: stem axis (f)<br />
tan: lilac bud scales (i), leaf scar (m)<br />
dark brown: bud scale scars (j), bundle scars (n),<br />
lenticels (o)<br />
gray-pink: stem growth, last year (k)<br />
gray: stem growth, 2 years ago (l)
Stem Tissues<br />
Meristems<br />
In the primary state <strong>of</strong> stem growth, the apical meristem<br />
at the shoot apex produces cells that differentiate<br />
into the three primary meristems. They are the ground<br />
meristem, which gives rise to pith, cortex <strong>of</strong> the stem<br />
and the mesophyll <strong>of</strong> leaves, the procambium, which<br />
produces primary xylem and phloem <strong>of</strong> the vascular<br />
system, and protoderm, which produces the epidermal<br />
system. In plants with secondary growth, the protoderm<br />
is replac<strong>ed</strong> by the vascular cambium. An intercalary<br />
meristem (a) is temporary, locat<strong>ed</strong> between tissues<br />
that already have differentiat<strong>ed</strong>. Examples include internodes<br />
<strong>of</strong> grasses and Equisetum; leaves <strong>of</strong> conifers<br />
and Welwitschia (see 74); fruiting stalks <strong>of</strong> peanut; and<br />
stipes <strong>of</strong> kelps (see 60).<br />
Ground Tissue System<br />
Dicot and Conifer Stems The ground tissue between<br />
vascular tissue (d) and epidermis (e) is cortex (f). It consists<br />
<strong>of</strong> parenchyma tissue with intercellular spaces, but<br />
may include sclerenchyma and collenchyma tissues.<br />
If the vascular tissue forms a ring between the cortex<br />
and the center <strong>of</strong> the stem, in the center is pith (g). In<br />
conifers, the cortex (f) may have resin ducts (h).<br />
Monocot Stem. With usually dispers<strong>ed</strong> vascular bundles<br />
(i) in the ground tissue, the parenchyma (j) is not<br />
differentiat<strong>ed</strong> into pith or cortex.<br />
Vascular Tissue System<br />
Dicot and Conifer Stems. Vascular bundles (d) are<br />
arrang<strong>ed</strong> in a ring around the stem. In primary growth,<br />
all cells <strong>of</strong> the procambium differentiate into primary<br />
vascular tissue (k, l). In plants with secondary growth,<br />
some <strong>of</strong> the meristematic cells remain and usually form<br />
a contiguous ring <strong>of</strong> vascular cambium (m), which begins<br />
to produce secondary phloem (n) outside, and secondary<br />
xylem (o) inside. The yearly additions <strong>of</strong> secondary<br />
xylem are commonly call<strong>ed</strong> “growth rings.” The<br />
ages <strong>of</strong> trees are determin<strong>ed</strong> by the number <strong>of</strong> growth<br />
rings in the trunk near the base <strong>of</strong> the tree trunk. Rings<br />
can be count<strong>ed</strong> visually or by use <strong>of</strong> an increment borer.<br />
The cambium forms two systems <strong>of</strong> vascular tissue,<br />
one vertically up the axis, and the other horizontally<br />
across the axis (call<strong>ed</strong> a ray system). Inward from the<br />
cambium, xylem rays (p) are produc<strong>ed</strong>, and outwardly<br />
phloem rays (q) are produc<strong>ed</strong>. Associat<strong>ed</strong> with the rays<br />
15<br />
are gum ducts in dicots, which contain resins, oil, gums,<br />
and mucilages. Comparable to gum ducts, some<br />
conifers have resin ducts. Secondary xylem tissue,<br />
“wood,” may be compos<strong>ed</strong> <strong>of</strong> sapwood (r) and heartwood<br />
(s). Sapwood consists <strong>of</strong> live xylem components,<br />
active in the transport <strong>of</strong> water and mineral nutrients.<br />
The inner heartwood is compos<strong>ed</strong> <strong>of</strong> inactive xylem<br />
that stores secondary metabolites. Organic compounds<br />
such as oils, gums, resins, and tannins fill the cells that<br />
prevent wood rot caus<strong>ed</strong> by fungi and other organisms.<br />
Monocot Stem. Monocots have no vascular or cork<br />
cambia and, therefore, no secondary growth. They exist<br />
in a primary state <strong>of</strong> growth (herbaceous plants). In<br />
large plant bodies such as palms, a thickening <strong>of</strong> the<br />
trunk occurs by multiple divisions <strong>of</strong> parenchyma cells<br />
<strong>of</strong> the procambium. In some members <strong>of</strong> the lily family<br />
(Liliaceae) such as Yucca and Dracaena, divisions outside<br />
the vascular bundles account for thickening <strong>of</strong> the<br />
stem axis.<br />
Secondary Dermal Tissue<br />
In woody dicots and conifers, the epidermis is replac<strong>ed</strong><br />
by periderm (t), “outer bark.” The periderm is compos<strong>ed</strong><br />
<strong>of</strong> cork cambium (phellogen, u), cork (phellum,<br />
v) and phelloderm (w). The cork cambium (u) produces<br />
phellem (v) toward the outside and phelloderm (w) toward<br />
the inside <strong>of</strong> the periderm. Cork cells at maturity<br />
are dead, and most are fill<strong>ed</strong> with suberin. The cork<br />
covering <strong>of</strong> stem surfaces functions for protection. It is<br />
compressible and water- and oil-resistant, and protects<br />
against insect and fungal attacks, cold, and, in some<br />
trees (e.g. r<strong>ed</strong>wood and sequoia), fire. Openings in the<br />
cork tissue, lenticels (x), serve, the same function as<br />
stomata in gas exchange. Secondary phloem (n) and<br />
periderm (t) together are commonly call<strong>ed</strong> “bark.”<br />
COLOR CODE<br />
r<strong>ed</strong>: intercalary meristem (a), vascular<br />
cambium (m), cork cambium (u)<br />
green: ridge (b), grooves (c), cortex (f),<br />
parenchyma (j)<br />
colorless: epidermis (e)<br />
yellow: resin ducts (h)<br />
orange: primary phloem (k)<br />
blue: primary xylem (l)<br />
light orange: secondary phloem(n), phloem rays (q)<br />
light blue: secondary xylem (o,r,s) xylem rays (p)<br />
tan: pith (g), periderm (t), cork (v, x),<br />
phelloderm (w)
Stem Modifications<br />
Stems may be <strong>of</strong> various forms to serve different functions,<br />
such as for food or water storage, for subterranean<br />
or aerial anchoring devices, as a means <strong>of</strong> asexual<br />
reproduction, or for climbing.<br />
Bulb. A bulb is a short, underground, food-storage<br />
stem axis with extremely r<strong>ed</strong>uc<strong>ed</strong> internodes and surrounding<br />
fleshy scale leaves (a). An onion is the example<br />
here.<br />
Corm. A solid, bulb-like, underground stem without<br />
fleshy scales forms a corm. It has greatly shorten<strong>ed</strong> internodes.<br />
Examples are the food-storage, reproductive<br />
corms <strong>of</strong> Gladiolus and Crocus (shown).<br />
Pseudobulb. Many orchids grow on branches or<br />
trunks <strong>of</strong> other plants (epiphytes). These plants develop<br />
a fleshy stem internode with water storage<br />
parenchyma. Other orchids, in contrast, are terrestrial<br />
(grow in the soil.)<br />
Rhizome. Found near or below the soil surface, a rhizome<br />
is an underground stem that produces scale-like<br />
leaves and adventitious roots at the nodes. Rhizomes<br />
are in Iris (see 129), Equisetum (see 20, 66), and Irish<br />
potato. A potato rhizome with a developing, <strong>ed</strong>ible tuber<br />
is shown.<br />
Spur Shoot. Some trees have short, woody stems<br />
with shorten<strong>ed</strong> internodes, such as apple (see 99) and<br />
Ginkgo (see 72). In apple, the spur shoots produce flowers<br />
and fruits. In Ginkgo, they produce pollen-producing<br />
male strobili on male trees or fruits from female strobili<br />
on female trees (dioecious condition, see 72).<br />
Stolon. A lateral stem, “runner” (k), from the base <strong>of</strong><br />
a plant develops long internodes, and where the apex<br />
touches the soil, a new plant with shoots and adventitious<br />
roots forms at a node. Strawberry (see 20) and<br />
strawberry begonia (shown) form stolons.<br />
16<br />
Succulent Stem. Fleshy water storage stems <strong>of</strong><br />
parenchyma are found in the spurge (see 103) and cactus<br />
(see 85) families. A fleshy cactus stem is shown.<br />
Other families containing representative genera with<br />
fleshy stems are found in the aster family (see 119)<br />
and geranium family (see 108).<br />
Tuber. Tubers are swollen, underground food storage<br />
stems arising at the tips <strong>of</strong> rhizomes. They bear buds,<br />
“eyes,” at the nodes on the potato tuber. These “eyes”<br />
develop into potato sprouts (shoots) when the potato<br />
starts to grow.<br />
Vine. Vines are stems with long internodes and may<br />
have one <strong>of</strong> various types <strong>of</strong> climbing devices such<br />
as tendrils opposite leaves at a node as in grape (see<br />
104), modifi<strong>ed</strong> stipule tendrils (w) as in green briar, disctipp<strong>ed</strong><br />
tendrils (t) as in Virginia creeper, adventitious<br />
roots as in philodendron and ivy (q), twining leaf tips as<br />
in gloriosa lily, and twining leaf petioles as in clematis,<br />
or the entire vine may twine as in wood rose (Ipomoea<br />
tuberosa).<br />
Of interest...A bizarre wide flattening <strong>of</strong> the stem in<br />
some plants is call<strong>ed</strong> fasciation (not shown), caus<strong>ed</strong><br />
by viruses, some bacterial pathogens, or herbicidal<br />
(2, 4-D) drift. The most familiar example is in crest<strong>ed</strong><br />
cockscomb (Celosia cristata). The condition can occur<br />
in herbaceous and in woody plants. Flowers may crowd<br />
together in a mass at the end <strong>of</strong> the flat stem.<br />
Witches’-broom is the term us<strong>ed</strong> to describe an abnormal<br />
bushy growth <strong>of</strong> stems that seem to originate<br />
from one point. A dense cluster <strong>of</strong> branches with no<br />
apical dominance forms. There are various causes depending<br />
on the species <strong>of</strong> herb or woody plant afflict<strong>ed</strong>:<br />
insects, bacteria, viruses, or fungi.<br />
COLOR CODE<br />
white: fleshy scale leaves (a), leaf buds (c),<br />
roots (j, q), potato rhizome and tuber<br />
yellow-tan: outer scale leaves (b)<br />
tan: onion stem axis, bud scale (d), scale<br />
covering (e, f), stem (o, r), tendril (t)<br />
light yellow: corm internodes, flower petals (i)<br />
green: leaf (g, n, s,), stem (m)<br />
purple-green: orchid pseudobulb (internode), stipe<br />
(h), leaf (l)<br />
purple-r<strong>ed</strong>: stolon (k)<br />
dark green: leaf (p)<br />
light green: stem (u), leaf (v), tendril (w)
Stem—Water Transport<br />
Transpirational “Pull”<br />
Water has a natural cohesiveness, surface tension, so<br />
will rise in a tube (capillary action), but not very high.<br />
How then does water rise from the soil to the leaves <strong>of</strong><br />
tall trees? The air surrounding mesophyll cells in leaf<br />
tissue (see 22) has a humidity <strong>of</strong> 100% and, thus, the<br />
tissue air is saturat<strong>ed</strong> with water. Air outside the plant<br />
usually has a lower humidity unless it is raining. The<br />
evaporation <strong>of</strong> moist air as it escapes the leaf tissue, via<br />
the pores (stomata), provides a “pull” for water movement<br />
within the plant.<br />
Loss <strong>of</strong> water by evaporation from leaf surfaces is call<strong>ed</strong><br />
transpiration. Water (a) moves upward in the plant<br />
from a region <strong>of</strong> higher water concentration in the soil to<br />
a region <strong>of</strong> lower water concentration, the dry air outside<br />
the leaves.<br />
Pathway <strong>of</strong> Water Transport<br />
Water (a) in the soil is absorb<strong>ed</strong> by the epidermal root<br />
hairs (b). It then moves across the root through living<br />
cortical cells (c), is “filter<strong>ed</strong>” through the semipermeable<br />
membranes <strong>of</strong> endodermal cells (d) passes through the<br />
pericycle (e), and enters the water-conducing cells (tracheids<br />
and vessel elements) <strong>of</strong> the xylem (f). Once in<br />
the xylem <strong>of</strong> the vascular system, water rises up the<br />
root to the stem and into the leaves.<br />
The maximum rate <strong>of</strong> water rise record<strong>ed</strong> in the roots<br />
<strong>of</strong> several oak species is 60 meters per hour. From<br />
the xylem, water enters the mesophyll tissue <strong>of</strong> the<br />
leaves and evaporates into the atmosphere via epidermal<br />
stomata when they are open. Much smaller<br />
amounts <strong>of</strong> water are lost from leaf cuticle and bark<br />
lenticels in the stems.<br />
Environmental Influences<br />
The rate <strong>of</strong> water transport in most plants is at a maximum<br />
during the daytime when air temperatures are<br />
high, relative humidity is low, and stomata are fully open.<br />
When the rate <strong>of</strong> water loss by transpiration exce<strong>ed</strong>s the<br />
rate <strong>of</strong> water uptake from soil, the stomata usually close.<br />
Many succulent plants that live in the desert open their<br />
stomata only at night in order to conserve water. Thus,<br />
water transport and transpiration in these plants occur<br />
primarily at night.<br />
17<br />
COLOR CODE<br />
blue: arrows, water (a), xylem (f)<br />
colorless: root hair (b), cortex (c)<br />
tan: endodermis (d)<br />
yellow: pericycle (e)<br />
orange: phloem (g)
Stem—Food Transport<br />
Translocation is the term us<strong>ed</strong> to designate transport<br />
<strong>of</strong> soluble organic materials (food) from one part <strong>of</strong> a<br />
plant to another. These organic materials are mainly<br />
sugars (from photosynthesis) and amino acids and<br />
amides (products <strong>of</strong> nitrogen metabolism). Primarily,<br />
they come from leaves, which we call sources, and are<br />
transport<strong>ed</strong> to areas call<strong>ed</strong> sinks, where they are either<br />
metaboliz<strong>ed</strong> or stor<strong>ed</strong>. Metabolic sinks include young,<br />
growing shoot tips (terminal and lateral), developing<br />
flower buds, growing stems, and elongating roots. Storage<br />
sinks include tubers, tuberous roots, bulbs, corms,<br />
fruits, or stem parenchyma tissue. The transport <strong>of</strong> organic<br />
solutes occurs in the phloem <strong>of</strong> the vascular system<br />
(see 11).<br />
At maturity, the sieve tube elements (see 8) <strong>of</strong> the<br />
phloem contain cytoplasm and cytoplasmic organelles<br />
but usually lack nuclei. Connecting strands, containing<br />
cytoplasm, pass through sieve areas on the end walls <strong>of</strong><br />
adjacent sieve-tube elements, which provide channels<br />
for flow <strong>of</strong> organic solutes from one sieve tube element<br />
to the next.<br />
Solute Transport in the Phloem<br />
Münch Pressure-Flow Theory<br />
One <strong>of</strong> the most satisfactory explanations that has been<br />
propos<strong>ed</strong> on long-distance transport <strong>of</strong> sugars in the<br />
phloem is the Münch Pressure-Flow Hypothesis. The<br />
diagram shows how it operates. Cells in the leaf (a)<br />
produce high amounts <strong>of</strong> sugar (b), which are actively<br />
(using ATP as an energy source) load<strong>ed</strong> into sieve tube<br />
elements (term<strong>ed</strong> “phloem loading,” c) in the veins.<br />
Because <strong>of</strong> the high concentration <strong>of</strong> sugar and low<br />
concentration <strong>of</strong> water, water (d) enters the sieve tube<br />
elements (e) from the xylem by osmosis (see 5). This<br />
causes a high water pressure, which drives the sugar<br />
“sap” (b–d) through the sieve tube elements to a sink<br />
such as a fruit (f) or a storage root (g). At the sink, the<br />
sugars are actively “unload<strong>ed</strong>” (h) into cells where they<br />
are us<strong>ed</strong> or stor<strong>ed</strong> as starch (a glucose polymer) or<br />
fructan (a fructose polymer). The high concentration <strong>of</strong><br />
water (d) that remains diffuses back into the xylem (i).<br />
18<br />
COLOR CODE<br />
orange: circles <strong>of</strong> sugar (b, c, h)<br />
blue: arrows <strong>of</strong> water (d)
Stem—Apical Dominance<br />
Apical dominance is the inhibition <strong>of</strong> the growth <strong>of</strong> axillary<br />
buds by the terminal bud <strong>of</strong> a shoot. When apical<br />
dominance is lost, axillary buds start to grow. This <strong>of</strong>ten<br />
occurs during flowering. In plants such as oats (Avena<br />
sativa) and sunflower (Helianthus annuus, a, b) with a<br />
very strong apical dominance, axillary buds may never<br />
develop during the vegetative phase <strong>of</strong> shoot development<br />
in both species, or in sunflower even when the<br />
plant is flowering (c).<br />
In plants such as wheat (Triticum) orColeus, where<br />
apical dominance is weak, axillary buds may start to<br />
grow. In Coleus, the lowest lateral buds on the primary<br />
shoot (d) develop into lateral shoots (e) first, and those<br />
near the top (f) last.<br />
In horticulture, “pinching <strong>of</strong>f” the shoot tip <strong>of</strong> a dicot<br />
plant removes the terminal bud, breaking apical dominance,<br />
and results in a “bushy” plant as the axillary<br />
buds form shoots. Removing terminal buds produces<br />
thickly branch<strong>ed</strong> h<strong>ed</strong>ge plants, more flower shoots in<br />
plant such as chrysanthemums and asters and encourages<br />
more foliage growth in dicot houseplants.<br />
In grasses, the shoots that develop from lateral buds<br />
are call<strong>ed</strong> tillers (h). Cereal grasses, such as wheat<br />
and rice (Oryza), that produce tiller shoots during the<br />
vegetative phase <strong>of</strong> shoot development, produce more<br />
19<br />
“heads” <strong>of</strong> flowers (inflorescences) during the reproductive<br />
phase, and hence, yield more grain (i) per plant than<br />
cereals that do not tiller until the reproductive phase<br />
is underway or after harvesting, such as oats and annual<br />
rye. Even corn produces “suckers” (tiller shoots),<br />
which are <strong>of</strong>ten remov<strong>ed</strong> to enhance yield in “ears” <strong>of</strong><br />
the main shoot.<br />
Apical dominance is regulat<strong>ed</strong> by two growth hormones:<br />
auxin (IAA, indole-3-acetic acid) from the terminal bud<br />
(k) and cytokinin (e.g., zeatin) from the roots. When the<br />
ratio <strong>of</strong> auxin to cytokinin decreases in favor <strong>of</strong> more<br />
cytokinins, apical dominance is lost and axillary buds<br />
are releas<strong>ed</strong> to expand.<br />
To demonstrate how auxin is involv<strong>ed</strong>, three alike plants<br />
with strong apical dominance can be us<strong>ed</strong>. One plant<br />
is us<strong>ed</strong> as a standard <strong>of</strong> comparison, the control. In<br />
another plant, the terminal bud is remov<strong>ed</strong> and lanolin<br />
paste (l) is appli<strong>ed</strong> to the cut surface. For the third plant,<br />
the apical bud is also remov<strong>ed</strong> and lanolin paste containing<br />
0.1% auxin (m) is appli<strong>ed</strong>. After a period <strong>of</strong> time,<br />
the results show that in the control plant and the plant<br />
with the auxin application, the axillary buds (n) have<br />
remain<strong>ed</strong> suppress<strong>ed</strong>. But in the plant without terminal<br />
bud or auxin application (lanolin only), apical dominance<br />
has been lost; the axillary buds are releas<strong>ed</strong> and<br />
develop into elongat<strong>ed</strong> shoots (o).<br />
COLOR CODE<br />
dark green: shoot (a), leaves (b)<br />
yellow: flower (c), lanolin (l)<br />
purple: shoots (d, e, f), leaves (g)<br />
green: tiller (h), leaves (j), terminal bud (k)<br />
lateral buds (n), lateral shoots (o)<br />
tan: grain (i)<br />
orange: lanolin with auxin (m)
Stem—Growth Movements<br />
A tropism is growth in response to an environmental<br />
stimulus. Growth in response to unequal light intensities<br />
is call<strong>ed</strong> phototropism, while growth stimulation<br />
by gravity is call<strong>ed</strong> gravitropism. When movement is<br />
toward the source <strong>of</strong> stimulation, it is positive, and when<br />
away from the stimulation source, it is a negative response.<br />
Phototropic Responses<br />
Positive Phototropism. Shoots exhibit positive phototropism<br />
by growing towards light. When a dark-grown<br />
oat se<strong>ed</strong>ling (a) is expos<strong>ed</strong> to a light source from the<br />
right, the shoot curves to the right (b) by cell elongation<br />
on the dark side. It was discover<strong>ed</strong> that a transmissible<br />
substance must be produc<strong>ed</strong> by the tip <strong>of</strong> the outermost<br />
se<strong>ed</strong>ling leaf, the coleoptile (c).<br />
If a piece <strong>of</strong> mica (d) is insert<strong>ed</strong> in the tip, no curvature<br />
occurs when a se<strong>ed</strong>ling is plac<strong>ed</strong> in a light source from<br />
the right. With the coleoptile tip cut <strong>of</strong>f (e), the shoot<br />
(f) does not curve toward the light. It is known that the<br />
hormone, auxin, is produc<strong>ed</strong> in the coleoptile tip. When<br />
a tip (g) is plac<strong>ed</strong> on an agar block (h) with a glass<br />
cover slip (i) dividing it, a greater concentration <strong>of</strong> auxin<br />
(j) arrives on the side <strong>of</strong> the block away from the light<br />
source.<br />
Negative Phototropism. Roots (l) exhibit negative<br />
phototropism by growing toward the center <strong>of</strong> gravity.<br />
Skototropism is a form <strong>of</strong> negative phototropism ex-<br />
20<br />
hibit<strong>ed</strong> by tropical vine shoots in which initial growth is<br />
toward dark shadows cast by trees blocking light. After<br />
the vine has climb<strong>ed</strong> the tree and reaches a lightexpos<strong>ed</strong><br />
area, it becomes positively phototropic.<br />
Gravitropic Responses<br />
Orthotropism. (Ortho = straight, correct, vertical.)<br />
Shoots (m) not only curve toward light (positively phototropic)<br />
but straight away from the earth’s center <strong>of</strong><br />
gravity (negatively gravitropic). Roots (n) and some fruit<br />
stalks show positive gravitropism by growing vertically<br />
toward the center <strong>of</strong> gravity. The root cap perceives the<br />
stimulus for the positive response, and auxin and other<br />
hormones regulate this growth process in the root.<br />
Plagiotropism. Plant parts that grow at an oblique angle<br />
from the vertical exhibit plagiotropism. Examples<br />
are lateral roots (p) and stems (q) that diverge from the<br />
main vertical axis.<br />
Diagravitropism. When plant parts grow at right angles<br />
to the line <strong>of</strong> gravity, they exhibit diagravitropism.<br />
Root<strong>ed</strong> rhizomes (s), stolons (v), horizontal branches,<br />
and horizontal leaf orientation are some examples.<br />
Agravitropism. Some plant parts are neutral to gravity<br />
and grow in various directions, such as the aerial roots<br />
<strong>of</strong> epiphytes (plants that grow upon other plants) and the<br />
flowering shoots <strong>of</strong> some plants that orient themselves<br />
in response to stimuli other than gravity.<br />
COLOR CODE<br />
white: shoots (a, b, e, f, g, m), roots (l, n, p),<br />
flower (y)<br />
tan: agar (h), se<strong>ed</strong> coat (k), rhizome (s),<br />
shoot (t)<br />
green: leaf cutting (o), stem (q), leaves (r, w),<br />
shoots (u), stolon (v)<br />
r<strong>ed</strong>: strawberry fruit (x)
Leaf Types and Arrangement<br />
Persistence<br />
Deciduous. A perennial plant is one that lives more<br />
than two years. Leaves that fall <strong>of</strong>f at the end <strong>of</strong> a growing<br />
period are call<strong>ed</strong> deciduous. Examples are found in<br />
maples (Acer), birches (Betula), and dogwoods (Cornus).<br />
Evergreen. Leaves that remain on a plant for more<br />
than a year are call<strong>ed</strong> evergreen. Pines (Pinus), spruces<br />
(Picea), rhododendrons (Rhododendron) are examples.<br />
Leaf Types<br />
Conifer. The leaves <strong>of</strong> conifers are ne<strong>ed</strong>le-like (a) as<br />
on pines or scale-like as on junipers (Juniperus). They<br />
are usually evergreen, although some conifers have deciduous<br />
leaves such as larches (Larix). Each conifer<br />
leaf has a single vein.<br />
Ginkgo. This unique plant (see 72) has fan-shap<strong>ed</strong><br />
leaf blades (c) with dichotomous venation in which the<br />
veins branch into two equal or unequal lengths. The<br />
leaves are deciduous and sh<strong>ed</strong> within a 24-hour period.<br />
Dicot. Most dicot blades have pinnate (feather-like) venation<br />
(e) in which major veins diverge from one large<br />
mid-vein, with smaller network connections between.<br />
Some dicot blades have palmate (hand-like) venation<br />
(i) where several large veins diverge from the petiole<br />
to the margins. Some dicots have parallel venation. An<br />
example is plantain (Plantago lanceolata).<br />
Monocot. Most Temperate Zone monocots have narrow<br />
strap-shap<strong>ed</strong> blades (f) with sheathing bases (g)<br />
surrounding the stem (h). With parallel venation, major<br />
veins arise at the base, remain more or less parallel,<br />
and converge at the tip with small vein interconnections.<br />
Some monocot leaf veins converge at the leaf margins<br />
instead <strong>of</strong> the tip, such as philodendron (Philodendron)<br />
21<br />
and some monocots have pinnate venation with Swiss<br />
cheese plant (Monstera) as an example.<br />
Leaf Attachment<br />
Petiolate. The leaf blade is attach<strong>ed</strong> to the stem by a<br />
stalk call<strong>ed</strong> a petiole (d).<br />
Sessile. When the leaf blade is attach<strong>ed</strong> directly to the<br />
stem without a petiole, it is sessile (a, f, n).<br />
Leaf Form<br />
Simple. A simple leaf has one blade, which may be<br />
broad (i) as in the maple leaf shown, narrow, or ne<strong>ed</strong>lelike<br />
(a).<br />
Compound. A compound leaf is one that has two or<br />
more blade-like leaftlets such as sumac (Rhus, j, pinnately<br />
compound) or clover (Trifolium, k, palmately compound)<br />
attach<strong>ed</strong> to a petiole (d).<br />
Leaf Arrangement<br />
Opposite. Two leaves (l) emerge opposite each other<br />
on a stem. The example shown is milkwe<strong>ed</strong> (Asclepias<br />
syriaca). Generally maples, ashes, dogwoods, and<br />
members <strong>of</strong> the honeysuckle Family (Caprifoliaceae)<br />
have opposite leaves. MAD Cap is an easy way to remember.<br />
Alternate. In an alternate arrangement, single leaves<br />
(m) are attach<strong>ed</strong> spirally along the stem. Lamb’s quarters<br />
(Chenopodium album) is shown (see 88). Most<br />
genera have alternate leaves.<br />
Whorl<strong>ed</strong>. In a whorl<strong>ed</strong> arrangement, several leaves (n)<br />
emerge together around a stem node. Michigan lily (Lilium<br />
michiganense) is the example shown (see 128).<br />
COLOR CODE<br />
blue-green: blade (a)<br />
green: shoot peg (b), petiole (d), blade (l, n)<br />
dark green: blade (e)<br />
yellow: blade (c)<br />
light green: blade (f, m), sheath (g), stem (h),<br />
leaflets(k)<br />
orange: blade (i)<br />
r<strong>ed</strong>: leaflets (j)
Leaf Types and Arrangement
Leaf Tissues<br />
The leaf blade’s outer surface is epidermal tissue and<br />
the ground tissue within is photosynthetic mesophyll, interspers<strong>ed</strong><br />
with “veins” (vascular bundles) <strong>of</strong> conducting<br />
(vascular) tissue. Vascular connections between blade<br />
and stem pass through the petiole.<br />
Dicot Leaf<br />
Epidermis. There may be one or more layers <strong>of</strong> epidermal<br />
cells (a) with cutiniz<strong>ed</strong> outer walls that form a<br />
waterpro<strong>of</strong> outer surface. Stomata <strong>of</strong> guard cells (b) are<br />
present on the upper and lower surface or only on the<br />
lower surface as shown here. Various hairs and glands<br />
may also be present (see 10).<br />
Ground Tissue. The parenchyma cells <strong>of</strong> the ground<br />
tissue (c) are divid<strong>ed</strong> into palisade (d) and spongy (e)<br />
mesophyll. Usually the columnar cells (f) <strong>of</strong> the palisade<br />
layer lie under the upper leaf epidermis and contain<br />
most <strong>of</strong> the chloroplasts <strong>of</strong> the ground tissue. The<br />
spongy parenchyma (e) has irregular-shap<strong>ed</strong> cells (g)<br />
with air spaces (h) between and lies above the lower<br />
leaf epidermis.<br />
Vascular Tissue. Four small vein transections are<br />
shown which are part <strong>of</strong> the vast, interconnecting network<br />
between major veins. A leaf vein (vascular bundle)<br />
usually has xylem (i) on the upper side and phloem (j) on<br />
the lower side. The reverse may be true in major veins.<br />
A layer <strong>of</strong> parenchyma cells call<strong>ed</strong> a bundle sheath (k),<br />
which functions in moving materials between the vein<br />
and the mesophyll tissue, usually encloses small veins.<br />
Monocot Leaf (Grass)<br />
Epidermis. Along with the epidermal cells (a), guard<br />
cells (b), hairs, silica, and cork cells, grass leaves have<br />
bulliform cells (l). The bubble-shap<strong>ed</strong>, water-fill<strong>ed</strong> bul-<br />
22<br />
liform cells control leaf rolling (when the leaf is dry) and<br />
unrolling (when the leaf is turgid or fill<strong>ed</strong> with water).<br />
Under drought conditions, bulliform cells collapse and<br />
the leaf rolls up.<br />
Ground Tissue. In the temperate region, grass mesophyll<br />
(c) consists <strong>of</strong> only spongy parenchyma tissue<br />
whose cells contain chloroplasts—sites <strong>of</strong> photosynthesis.<br />
Vascular Tissue. Grass leaves have bundle sheaths<br />
(k) surrounding each vein. Sclerenchyma fiber strands<br />
(m) may be associat<strong>ed</strong> with the veins. (Leaf transection<br />
adapt<strong>ed</strong> with permission: Esau, K., Plant Anatomy,<br />
1967, John Wiley & Sons.)<br />
Conifer Leaf<br />
Epidermis. The usually small, triangular or flat “ne<strong>ed</strong>le”<br />
leaves <strong>of</strong> conifers are adapt<strong>ed</strong> to dry conditions.<br />
Epidermal cells (a) have thick walls <strong>of</strong> cuticle, and<br />
sunken stomatal guard cells (b) overlapp<strong>ed</strong> on the surface<br />
by subsidiary cells (n). Stomata may be on one<br />
or all sides <strong>of</strong> the leaf surface. Under the epidermis<br />
may be a layer <strong>of</strong> thick-wall<strong>ed</strong> sclerenchyma cells call<strong>ed</strong><br />
hypodermis (o).<br />
Ground Tissue. Mesophyll tissue (c) is not usually differentiat<strong>ed</strong><br />
into palisade and spongy layers. Resin ducts<br />
(p) are present.<br />
Vascular Tissue. There are one or two veins in the<br />
center surround<strong>ed</strong> by transfusion tissue (q) and endodermis<br />
(r) containing tannins and resins.<br />
COLOR CODE<br />
colorless: epidermal cells (a), air space (h),<br />
bulliform cells (l), subsidiary cells (n),<br />
hypodermis (o), transfusion tissue (q)<br />
green: guard cells (b), monocot and conifer<br />
mesophyll (c) palisade parenchyma<br />
cells (f)<br />
light green: spongy parenchyma cells (g), bundle<br />
sheath (k)<br />
blue: xylem (i)<br />
orange: phloem (j)<br />
tan: sclerenchyma fibers (m), endodermis (r)<br />
yellow: resin duct (p)
Leaf Modifications<br />
Leaves may become highly specializ<strong>ed</strong> in function, exhibiting<br />
bizarre forms. Only a few <strong>of</strong> the many leaf modifications<br />
are shown here.<br />
Bract. Associat<strong>ed</strong> with a flower, bracts are r<strong>ed</strong>uc<strong>ed</strong> or<br />
modifi<strong>ed</strong> leaves. Very small bracts are found in s<strong>ed</strong>ge<br />
and grass flowers (see 122, 123), while large colorful<br />
bracts (a) subtend flowers (b) such as Bougainvillea<br />
and poinsettia (Euphorbia). The spathe is an elaborate<br />
bract found in the arum family (see 127).<br />
Carnivorous Leaves. Carnivorous plants live in lownitrogen<br />
environments and enzymatically digest animals<br />
(mainly insects) in their leaves to supplement nutritional<br />
ne<strong>ed</strong>s. The Venus’- flytrap (Dionaea)withatwolob<strong>ed</strong><br />
leaf blade (c, d) has trigger hairs (e) that set <strong>of</strong>f<br />
a response that brings the spine-cover<strong>ed</strong> leaf margins<br />
(f) together in a closing trap. The leaf has a wide petiole<br />
(g). On butterwort (Pinguicula, see 10) and sundew<br />
(Drosera) leaves (h), long, sticky-bulb<strong>ed</strong>, glandular<br />
hairs (i) entrap and digest insects.<br />
In pitcher-plants (Sarracenia), the hairy (j) lower surface<br />
<strong>of</strong> the leaf blade (k) is curv<strong>ed</strong> inward, forming a well<br />
<strong>of</strong> water and digestive enzymes. Nectar glands attract<br />
insects, while downward point<strong>ed</strong> hairs keep them in the<br />
leaf enclosure (see 91). The carnivorous leaf colors <strong>of</strong><br />
the above examples attract flies (see 34).<br />
A water plant, bladderwort (Utricularia) has bait and<br />
trigger hairs (o) surrounding the mouth (p) <strong>of</strong> a bladder<br />
23<br />
(q), a modifi<strong>ed</strong> leaf. Movement <strong>of</strong> the hairs entices small<br />
crustaceans to investigate. By negative pressure within<br />
the bladder, victims are suck<strong>ed</strong> in and digest<strong>ed</strong>, seal<strong>ed</strong><br />
in by a trap door at the mouth <strong>of</strong> the bladder.<br />
Phyllode. This is a widen<strong>ed</strong> petiole that appears bladelike.<br />
In the acacia (Acacia melanoxylon) plant, some<br />
leaves consist <strong>of</strong> only petioles (phyllodes, r), while others<br />
develop compound leaflets (s).<br />
Spine. Spines are highly r<strong>ed</strong>uc<strong>ed</strong> leaves or stipules<br />
found on many herbs, shrubs, and trees. Often a plant<br />
exhibits a series <strong>of</strong> forms (homology) from leaf (t) to<br />
spine (u).<br />
Stipule. Usually in pairs, stipules (v) are basal appendages<br />
to the petiole (w). They may appear as hairs,<br />
leaves, tendrils, or spines.<br />
Succulent Leaves. An adaptation to dry environments,<br />
some plants store water in leaf mesophyll tissue.<br />
The epidermis may have thick cutiniz<strong>ed</strong> and lignifi<strong>ed</strong><br />
walls to r<strong>ed</strong>uce water loss. In some succulents, the<br />
stomata reverse the usual condition and open only at<br />
night. The leaf epidermis (y) <strong>of</strong> living stones (Lithops),<br />
an example <strong>of</strong> mimicry, appears sand-color<strong>ed</strong>. In<br />
the cut-away drawing, green mesophyll tissue (z) is<br />
expos<strong>ed</strong>, surrounding the newly form<strong>ed</strong> leaf in the<br />
center.<br />
COLOR CODE<br />
r<strong>ed</strong>: bracts (a), inner blade surface (c),<br />
hairs (i, j), veins (l)<br />
white: flower (b), hairs (e)<br />
yellow-green: blade margins (f), petiole (g), blade (d)<br />
green: leaf (h, n), leaflets (s)<br />
light green: petiole (m), blade (k), leaf (t), stipule<br />
(v), mesophyll (z)<br />
tan: hairs (o), bladder (q), spine (u),<br />
epidermis (y)<br />
dark green: petiole (r, w), blade (x)
Leaf—Photosynthesis<br />
Plant Energy Source<br />
Photosynthesis is the process in plants in which light<br />
energy is convert<strong>ed</strong> to useful chemical energy. In the<br />
process, carbon dioxide and water, in the presence<br />
<strong>of</strong> chlorophyll and light energy, form sugars, oxygen,<br />
chemical energy (ATP—adenosine triphosphate), and<br />
water. A general equation is shown.<br />
With the exception <strong>of</strong> fungi, photosynthesis occurs in<br />
all major groups <strong>of</strong> organisms discuss<strong>ed</strong> in this book,<br />
including certain bacteria. Most plants that photosynthesize<br />
have chloroplasts, in which photosynthesis occurs.<br />
Other cells, as in photosynthetic bacteria and bluegreens,<br />
have no chloroplasts. Instead photosynthesis<br />
occurs in pigments locat<strong>ed</strong> in the cytoplasm.<br />
Significance <strong>of</strong> Photosynthesis<br />
Photosynthesis is responsible for the conversion <strong>of</strong><br />
carbon from carbon dioxide into organic compounds<br />
in plants. It allows the plant to make organic building<br />
blocks for sugars, amino acids, nucleic acids, fatty<br />
acids, new cells, starch, protein, DNA and RNA, hormones<br />
and vitamins, and many secondary compounds.<br />
Without this photosynthetic process, life would not exist<br />
on earth. Plants provide, directly or indirectly, food<br />
for all animals and all <strong>of</strong> our atmospheric oxygen. They<br />
also “fix” CO2 in photosynthesis, which helps to r<strong>ed</strong>uce<br />
global warming.<br />
Photosynthesis consists <strong>of</strong> two basic parts: a series <strong>of</strong><br />
light reactions and a series <strong>of</strong> dark reactions. In the light<br />
reaction (a), chlorophyll a (and accessory pigments)<br />
absorb light, which “excites” the electrons in the chlorophyll<br />
molecule. The electrons are pass<strong>ed</strong> along through<br />
a series <strong>of</strong> carriers (acceptors), and energy (ATP) is produc<strong>ed</strong>,<br />
which catalyzes the dark reaction. During the<br />
light reactions, water is split, giving <strong>of</strong>f oxygen.<br />
24<br />
In the dark reaction (b), carbon dioxide, products <strong>of</strong> the<br />
light reaction (r<strong>ed</strong>ucing power), and energy are us<strong>ed</strong>.<br />
Carbon dioxide is “fix<strong>ed</strong>” or convert<strong>ed</strong> into a cyclic production<br />
<strong>of</strong> a series <strong>of</strong> carbon sugars, the most important<br />
<strong>of</strong> which ultimately is sucrose, made up <strong>of</strong> 6-carbon<br />
sugars, glucose, and fructose.<br />
C3 and C4 Plants<br />
In regard to photosynthesis, plants are divid<strong>ed</strong> into two<br />
types: C3 and C4 plants. In the leaves <strong>of</strong> C3 plants, which<br />
include most plants, light-driven carbon fixation reactions<br />
involve the formation <strong>of</strong> 3-carbon organic acids<br />
as the first stable products. In many tropical grasses<br />
C4 photosynthesis, such as sugar cane, corn, and<br />
sorghum, the photosynthetic process is more efficient.<br />
The grass bundle sheath (see 22) produces 3-carbon<br />
acids and sugars, whereas the mesophyll tissue produces<br />
4-carbon acids. These plants are more efficient<br />
in producing sugars because they have little or no sugar<br />
loss during respiration (a chemical release <strong>of</strong> energy<br />
from sugars) in the light (photorespiration).<br />
The illustration shows where the photosynthetic process<br />
takes place in the leaf (c) <strong>of</strong> a C3 plant. In the<br />
chloroplast (i), chlorophylls and accessory pigments are<br />
locat<strong>ed</strong> in the thylakoids (j), where the light reaction<br />
takes place. Dark reactions take place in the stroma (k)<br />
<strong>of</strong> the chloroplast (see 3).<br />
Environmental Regulation <strong>of</strong> Photosynthesis<br />
Photosynthetic rate is regulat<strong>ed</strong> by the intensity <strong>of</strong> light,<br />
daylength, amounts <strong>of</strong> carbon dioxide and oxygen in<br />
the air (or water for water plants), temperature, and the<br />
level <strong>of</strong> air pollution.<br />
COLOR CODE<br />
green: light reaction (a), leaf (c), guard cells (e),<br />
palisade cells (h) with chloroplasts (i),<br />
thylakoid (j)<br />
gray: dark reaction (b), stroma (k)<br />
blue: water (xylem) in vein (d)<br />
orange: sugars (phloem) in vein (d)<br />
colorless: epidermis (f), spongy cells (g)
Leaf—Nutrient Deficiency Symptoms<br />
The essential elements that are requir<strong>ed</strong> for the healthy<br />
growth <strong>of</strong> higher plants are carbon, hydrogen, oxygen,<br />
and those list<strong>ed</strong> below. Plants take in carbon in the form<br />
<strong>of</strong> atmospheric carbon dioxide, obtain hydrogen and<br />
oxygen from water, and take up the remaining elements<br />
from the soil. By growing plants in an aqueous nutrient<br />
solution (hydroponics) and omitting an essential nutrient,<br />
specific deficiency symptoms can be observ<strong>ed</strong>.<br />
Nitrogen. Decaying organic matter provides soil nitrogen.<br />
Also, nitrogen-fixing bacteria on some plant<br />
roots convert atmospheric nitrogen into organic forms<br />
us<strong>ed</strong> by plants. Nitrogen deficiency results in yellowing<br />
(chlorosis) <strong>of</strong> older leaves.<br />
Phosphorus. Plants deficient in this element exhibit<br />
dark green older leaves and stunt<strong>ed</strong> growth. R<strong>ed</strong> anthocyanin<br />
pigments sometimes accumulate.<br />
Potassium. This element is found in wood ashes<br />
(potash). Deficiency symptoms are exhibit<strong>ed</strong> in older<br />
leaves that yellow and have dead (necrotic) tissue in<br />
spots, and roots are easily infect<strong>ed</strong> with pathogenic organisms.<br />
Magnesium. A lack <strong>of</strong> magnesium results in a yellowing<br />
<strong>of</strong> the leaves between the veins with the tips and<br />
margins turning upward.<br />
Sulfur. Usually, a sulfur deficiency affects the younger<br />
leaves first with the veins becoming light green and a<br />
yellowing <strong>of</strong> the tissue between them. As sulfur compounds<br />
are found in most soils, this deficiency is rare.<br />
25<br />
Calcium. Lack <strong>of</strong> calcium affects meristematic regions,<br />
resulting in the death <strong>of</strong> terminal buds and root tips.<br />
Iron. A deficiency <strong>of</strong> iron results in a chlorosis <strong>of</strong> young<br />
leaves with the yellowing occurring between veins.<br />
Chlorine. Without chlorine, leaves wilt, turn yellow,<br />
show dead spots, and then become a bronze color.<br />
Roots become stunt<strong>ed</strong> and club-shap<strong>ed</strong> near the tips.<br />
Manganese. Although a rarely found deficiency, without<br />
manganese, younger leaves form yellow speckles<br />
between the veins.<br />
Boron. Lack <strong>of</strong> boron produces death <strong>of</strong> shoot and<br />
root apical meristems, beginning with young leaves becoming<br />
light green at the base, and root tips becoming<br />
swollen.<br />
Zinc. A deficiency <strong>of</strong> zinc results in formation <strong>of</strong> small<br />
leaves and shorten<strong>ed</strong> stem internodes. The leaf margins<br />
may become distort<strong>ed</strong>.<br />
Copper. A rare deficiency, lack <strong>of</strong> copper produces<br />
dark green, twist<strong>ed</strong> young leaves, which <strong>of</strong>ten have<br />
dead spots.<br />
Molybdenum. Lack <strong>of</strong> this element produces chlorosis<br />
<strong>of</strong> old and midstem leaves, and eventually affects the<br />
young leaves.<br />
COLOR CODE<br />
green: terminal bud (a), new leaf (b), middle<br />
leaf (c), old leaf (d), veins (e)<br />
tan: roots (f)<br />
light green: chlorosis (g)<br />
yellow: late-stage chlorosis (h)<br />
brown: dead tissue (i)<br />
dark green: pigment accumulation (j)<br />
r<strong>ed</strong>-purple: anthocyanin pigmentation (k)<br />
r<strong>ed</strong>-brown: damag<strong>ed</strong> tissue (l)
Flower Initiation in Response to Daylength<br />
Plants are classifi<strong>ed</strong> as short-day, long-day, or dayneutral<br />
in terms <strong>of</strong> their flowering response to daylength<br />
(photoperiod). Most plants are day-neutral. They are<br />
not induc<strong>ed</strong> to flower by either long or short photoperiods.<br />
In the tropics, where photoperiods do not change<br />
nearly as much as in temperate regions, most plants<br />
are day-neutral or long-day in their response to photoperiod.<br />
Short-day Plants<br />
It has been found that rather than the length <strong>of</strong> daylight<br />
time, it is actually the length <strong>of</strong> the dark period<br />
(night length time) that induces flowering in short-day<br />
plants. If poinsettias are briefly illuminat<strong>ed</strong> during their<br />
long-night period, the flowering response is not induc<strong>ed</strong>.<br />
Short-day plants grow vegetatively (a) during<br />
long-day periods and flower (b) during short-day periods.<br />
Some examples <strong>of</strong> short-day plants are poinsettia<br />
(Euphorbia pulcherrima), thanksgiving cactus (Schlumbergera<br />
truncata), chrysanthemum (Chrysanthemum),<br />
lamb’s quarters (Chenopodium album), cocklebur<br />
(Xantium strumarium), strawberry (Fragaria), and many<br />
varieties <strong>of</strong> rice (Oryza).<br />
The nature <strong>of</strong> the flowering stimulus in short-day plants<br />
is not yet known. However, the stimulus most likely<br />
involves an interaction between flower-inhibitor and<br />
flower-promoter type hormones. The evidence that ini-<br />
26<br />
tiation <strong>of</strong> flowers involves hormones is that the signal<br />
can be perceiv<strong>ed</strong> by one mature leaf.<br />
Using cocklebur plants, if one mature leaf (c) is expos<strong>ed</strong><br />
to short days while the rest <strong>of</strong> the plant is expos<strong>ed</strong> to<br />
long days, flowering will result. Furthermore, by grafting<br />
a branch from a cocklebur plant given short days onto<br />
a cocklebur plant given long days, flowering is induc<strong>ed</strong><br />
in the stems given long days.<br />
Long-day Plants<br />
Plants that require long days (short nights) for flowering<br />
include spinach (Spinacia oleracea), winter barley<br />
(Hordeum vulgare), winter wheat (Triticum aestivum),<br />
oats (Avena sativa), perennial ryegrass (Lolium<br />
perenne), clover (Trifolium pratense), coneflower (Rudbeckia),<br />
dill (Anethum graveolens), rose-<strong>of</strong>-sharon (Hibiscus<br />
syriacus), petunia (Petunia), and all biennials.<br />
Biennials are plants with a 2-year growth cycle. They<br />
require cool winter temperatures the first year, and long<br />
days the second year for flower induction.<br />
Some plants cannot be induc<strong>ed</strong> to flower by exposure to<br />
critical daylength periods until a certain age is reach<strong>ed</strong>.<br />
Depending on the species, some trees are not “flowermature“<br />
until 5 to 40 years <strong>of</strong> age. For example, a sugar<br />
maple tree (Acer saccharum) may not flower until it is<br />
30 years old, but it can live 200 to 300 years.<br />
COLOR CODE<br />
r<strong>ed</strong>: tepals (d)<br />
green: stems (e, f, I), leaves (g, j), p<strong>ed</strong>uncle (k)<br />
tan: fruit(h)<br />
yellow: rays (l)<br />
brown: flowers (m)
Flower Structure<br />
Parts <strong>of</strong> a Flower<br />
P<strong>ed</strong>uncle. The stalk that attaches the flower to the<br />
plant axis is call<strong>ed</strong> a p<strong>ed</strong>uncle (a). A p<strong>ed</strong>icel is the<br />
stalk <strong>of</strong> a single flower in a cluster (inflorescence) with<br />
the p<strong>ed</strong>icels attach<strong>ed</strong> to a p<strong>ed</strong>uncle ( see 98, 100, 109).<br />
Receptacle. The enlarg<strong>ed</strong> part <strong>of</strong> the flower axis where<br />
floral parts are borne is the receptacle (b).<br />
Sepals. The outermost whorl <strong>of</strong> floral parts are leaflike<br />
structures call<strong>ed</strong> sepals (c). While usually green,<br />
they may be color<strong>ed</strong> in some species (see 129, 130).<br />
Sepals protect the developing flower in the bud stage.<br />
All <strong>of</strong> the sepals, collectively, make up the calyx.<br />
Petals. The second whorl <strong>of</strong> floral appendages are<br />
petals (d), which may be separate or partially fus<strong>ed</strong><br />
together. Usually, they are showy and may be color<strong>ed</strong>.<br />
All <strong>of</strong> the petals, collectively, make up the corolla.<br />
Tepals. When the calyx and corolla look alike and are<br />
petal-like, they are call<strong>ed</strong> tepals (see 126, 128).<br />
Perianth. This term is us<strong>ed</strong> to refer to the calyx and<br />
corolla together.<br />
Stamen. A stamen consists <strong>of</strong> a stalk-like filament (e)<br />
with an anther (f), made up <strong>of</strong>, usually, 2 pollen sacs,<br />
at the upper end. The connective (g) joins the pollen<br />
sacs containing pollen grains (h) (see 31). All <strong>of</strong><br />
27<br />
the stamens, collectively, are term<strong>ed</strong> the androecium<br />
(= male household).<br />
Pistil. A pistil is made up <strong>of</strong> stigma, style, and ovary.<br />
At the apex <strong>of</strong> the pistil is the stigma (i), where pollen<br />
grains adhere to the sugary, liquid excretions on the<br />
surface. Between the stigma and ovary is an elongat<strong>ed</strong><br />
part <strong>of</strong> the pistil call<strong>ed</strong> the style (j). The ovary (k) consists<br />
<strong>of</strong> one or more carpels, which contain the ovules<br />
(see 28). Within the ovule (l), megaspores are form<strong>ed</strong>,<br />
one <strong>of</strong> which develops into the embryo sac containing<br />
an egg (see 31).<br />
After fertilization, the ovules develop into se<strong>ed</strong>s (see<br />
37). That part <strong>of</strong> the carpel where the ovules are attach<strong>ed</strong><br />
is the placenta (see 28). A locule (m) is the<br />
chamber or space within a carpel. All <strong>of</strong> the pistils<br />
within a flower are call<strong>ed</strong>, collectively, the gynoecium<br />
(= female household).<br />
Number <strong>of</strong> Parts<br />
In a broad generalization, dicot flowers tend to have<br />
floral parts in whorls <strong>of</strong> 4 to 5 and monocots in series<br />
<strong>of</strong> 3. For example, a dicot flower might have<br />
4 sepals, 4 petals, and 8 stamens or 5 sepals, 5 petals,<br />
and 15 stamens. A monocot flower might have 3 sepals,<br />
3 petals, and 6 stamens. When observing flowers, it is<br />
interesting to determine number patterns. Numbers <strong>of</strong><br />
floral parts are also us<strong>ed</strong> in “keying out” plants (plant<br />
identification).<br />
COLOR CODE<br />
light green: p<strong>ed</strong>uncle (a), stigma (i), style (j)<br />
white: receptacle (b), filament (e), ovary (k),<br />
ovules (l)<br />
green: sepals (c)<br />
optional: petals (d)<br />
yellow: anther (f), connective (g), pollen (h)
Flower Structure Variations<br />
Types <strong>of</strong> Flowers<br />
Unisexual (Imperfect). A unisexual flower has either<br />
staminate (male) (a) or pistillate (female) (b) structures.<br />
Bisexual (Perfect). A bisexual flower has staminate (a)<br />
and pistillate (b) structures.<br />
Monoecious (= <strong>of</strong> one house). An individual plant with<br />
separate (unisexual) staminate and pistillate flowers is<br />
term<strong>ed</strong> monoecious (see 94).<br />
Dioecious (= <strong>of</strong> two houses). The term, dioecious, is<br />
us<strong>ed</strong> when a species has separate staminate-flower<strong>ed</strong><br />
plants and pistillate-flower<strong>ed</strong> plants (see 105).<br />
Polygamomonoecious. An individual plant with bisexual<br />
flowers plus staminate or pistillate unisexual<br />
flowers is polygamomonoecious (poly = many;<br />
gamete = sex cell).<br />
Complete. A complete flower has staminate (a) and<br />
pistillate (b) structures, plus sepals (c) and petals (d).<br />
Incomplete. An incomplete flower lacks one or more<br />
floral parts. The incomplete flower shown lacks petals.<br />
Ovary Positions<br />
Superior. The superior ovary (f) <strong>of</strong> the pistil is above<br />
the site <strong>of</strong> attachment <strong>of</strong> other floral parts (stamens,<br />
sepals, petals).<br />
28<br />
Inferior. The inferior ovary (f) is below the site <strong>of</strong> attachment<br />
<strong>of</strong> other floral parts.<br />
Half-inferior or Half-superior. These are flowers that<br />
show varying degrees <strong>of</strong> ovary (f) position from partially<br />
superior to partially inferior.<br />
Placentation<br />
Axile. By fusion <strong>of</strong> 2 or more carpels (g), the ovules (h)<br />
are attach<strong>ed</strong> to the placenta (i) at the central axis (axile<br />
placentation).<br />
Free Central. Fus<strong>ed</strong> carpels (g) have lost their inner<br />
walls and the placenta (i) is locat<strong>ed</strong> in the center (free<br />
central placentation). Examples are members <strong>of</strong> the<br />
pink family (Caryophyllaceae, see 87) and nightshade<br />
family (Solanaceae, see 111, pepper).<br />
Basal. The placenta (i) is locat<strong>ed</strong> at the base <strong>of</strong> the<br />
ovary (basal placentation).<br />
Parietal. The placenta (i) is locat<strong>ed</strong> on the inner walls<br />
<strong>of</strong> carpels, which do not extend into the center <strong>of</strong> the<br />
ovary (parietal placentation).<br />
COLOR CODE<br />
yellow: stamen (a)<br />
light green: pistil (b), ovary (f), carpel wall (g), ovules<br />
(h)<br />
green: sepals (c), p<strong>ed</strong>uncle (e)<br />
blue: petals (d)<br />
white: ovules (h), placenta (i)
Flower Development<br />
Flower Bud<br />
Early Stage. Above the p<strong>ed</strong>uncle (a), upright bracts (b)<br />
cover the sepals (c). The sepals enclose the developing<br />
petals (d), anthers (e), and the column <strong>of</strong> fus<strong>ed</strong> staminal<br />
filaments (f).<br />
Interm<strong>ed</strong>iate Stage. At this stage, the receptacle (g)<br />
expands and a young pistil (h) within the column (i) can<br />
be seen. At the top <strong>of</strong> the pistil, stigmas (j) form, the<br />
style (k) begins to elongate, and the ovary (l) enlarges.<br />
Late Stage. The fold<strong>ed</strong> petals (m) emerge from the<br />
sepals (n). Within, the filament column (p) has elongat<strong>ed</strong><br />
and the stigmas (q) have emerg<strong>ed</strong> as the style (r)<br />
elongates. The superior ovary (l) has developing ovules<br />
(s) within the carpels.<br />
Mature Flower<br />
Bracts (b) are separate from the basally fus<strong>ed</strong> sepals (n)<br />
and the five petals (m) are expand<strong>ed</strong>. The fully-form<strong>ed</strong><br />
fus<strong>ed</strong> filament column (t) protrudes above the petals.<br />
Anthers (o) are fully mature on short filaments (u), which<br />
separate from the column. Five stigmas (q) on a divid<strong>ed</strong><br />
style (v) rise above the column.<br />
Anthesis. is the term us<strong>ed</strong> for the time when a flower<br />
comes into full bloom. It is a time when the flower is fully<br />
expand<strong>ed</strong>.<br />
29<br />
COLOR CODE<br />
dark green: p<strong>ed</strong>uncle (s), bracts (b), sepals (c)<br />
light green: petals (d), filament column (i)<br />
white: anthers (e), filament column (f, p),<br />
receptacle (g), pistil (h), stigma (j), style<br />
(k, r), ovary (l), ovules (s)<br />
green: sepals (n)<br />
r<strong>ed</strong>: petals (m)<br />
yellow: anthers (o)<br />
dark r<strong>ed</strong>: stigmas (q), filament column (t),<br />
filaments (u), style (v)
Flower—Meiosis<br />
Each species has a specific number (2n) <strong>of</strong> chromosomes<br />
in the nucleus <strong>of</strong> each <strong>of</strong> its body (somatic) cells.<br />
Half <strong>of</strong> the chromosomes (1n) come from one parent<br />
and half (1n) from the other parent. For new body cells<br />
to form, 2n (diploid) cells divide by mitosis into more 2n<br />
cells.<br />
For an individual to become a parent, it must produce 1n<br />
(haploid) cells that can fuse with 1n (haploid) cells from<br />
another individual. The process <strong>of</strong> producing haploid<br />
cells from diploid cells is call<strong>ed</strong> meiosis.<br />
In higher plants, the end products <strong>of</strong> meiosis are haploid<br />
pollen grains in the anthers <strong>of</strong> the stamen and a haploid<br />
egg in each ovule <strong>of</strong> the pistil. In lower plants, the end<br />
products <strong>of</strong> meiosis are 1n (haploid) gametes (= sex<br />
cells).<br />
Stages <strong>of</strong> Meiosis<br />
Meiosis has 2 basic stages: (l), the r<strong>ed</strong>uction stage, and<br />
(II), the division stage. Unlike mitosis, during meiosis,<br />
chromosomes come together in pairs, call<strong>ed</strong> homologous<br />
pairs. Each chromosome <strong>of</strong> the pair has the same<br />
gene alignment and each represents a different parent.<br />
This pairing is significant because, during meiosis,<br />
“crossing over” (chiasmata) with an exchange <strong>of</strong> genes<br />
is possible (see 6).<br />
It is now obvious that the 2n (diploid) number is an even<br />
number for normal pairing to occur. The cells that undergo<br />
meiosis are call<strong>ed</strong> “mother cells.” Within each<br />
<strong>of</strong> the 2 stages <strong>of</strong> meiosis are 4 phases: prophase,<br />
metaphase, anaphase, and telophase.<br />
Prophase l. During early prophase, the 2n chromosomes<br />
(a, b, c) become visible as threads and then<br />
come together in homologous pairs. (For simplicity,<br />
only 3 pairs <strong>of</strong> chromosomes are shown within a nucleus.)<br />
Then each chromosome separates to form<br />
30<br />
2 chromatids held together at the centromere (d).<br />
“Crossing over” (e) <strong>of</strong> chromatid strands results in chiasmata<br />
(sing.: chiasma), which are visible sites <strong>of</strong> exchang<strong>ed</strong><br />
genetic material (f).<br />
Metaphase l. At this phase, the chromatids are position<strong>ed</strong><br />
so that the centromeres are align<strong>ed</strong> on either<br />
side <strong>of</strong> the equatorial plane <strong>of</strong> the spindle apparatus<br />
(g).<br />
Anaphase l. Next, the pair<strong>ed</strong> chromatids separate and<br />
move to opposite poles (h).<br />
Telophase l. Lasting only a short time, telophase completes<br />
the r<strong>ed</strong>uction stage with the original number (2n)<br />
<strong>of</strong> chromosomes r<strong>ed</strong>uc<strong>ed</strong> to half (1n).<br />
Prophase ll. The second division stage <strong>of</strong> meiosis is<br />
essentially like mitosis (see 7).<br />
Metaphase ll. During this phase, the chromatids align<br />
in the center <strong>of</strong> the plane <strong>of</strong> the spindle.<br />
Anaphase ll. The centromeres (d) divide and chromosomes<br />
move to opposite poles (h) <strong>of</strong> the spindle.<br />
Telophase ll. By this phase, the chromosomes have<br />
complet<strong>ed</strong> their migration to the spindle poles. As a result,<br />
4 1n products are form<strong>ed</strong>. The chromosomes (i, j,<br />
k) now have a different genetic makeup than the chromosomes<br />
<strong>of</strong> the original 2n cell.<br />
This meiotic description is characteristic <strong>of</strong> higher plants<br />
when 4 haploid products are form<strong>ed</strong>. In flowering plants,<br />
in the ovule <strong>of</strong> the pistil, 3 <strong>of</strong> these nuclei usually disintegrate<br />
and the 4th divides (mitotically) repeat<strong>ed</strong>ly to form<br />
the nuclei <strong>of</strong> the embryo sac, one <strong>of</strong> which is the 1n egg<br />
nucleus. In the anther sac <strong>of</strong> the stamen, all 4 products<br />
<strong>of</strong> meiosis remain alive and develop into tetrads (4’s) <strong>of</strong><br />
1n (haploid) pollen grains.<br />
COLOR CODE<br />
orange: chromosomes (a)<br />
yellow: chromosomes (b)<br />
green: chromosomes (c)<br />
purple: centromere (d)<br />
colorless: spindle (g)<br />
blue: chromosomes (i, j, k)
Flower—Pollen Development<br />
Young Stamen<br />
Once flower primordia are initiat<strong>ed</strong>, stamens begin to<br />
develop. The stamen in a flower consists <strong>of</strong> a filament<br />
(a) and an anther (b) with, usually, 2 pollen sacs<br />
(c). Pollen formation takes place within the chambers<br />
(locules) <strong>of</strong> the pollen sac (microsporangium). Each<br />
chamber is surround<strong>ed</strong> by a layer <strong>of</strong> cells call<strong>ed</strong> the<br />
tapetum (d), which functions as a source <strong>of</strong> nutrition<br />
for the 2n microspore mother cells (e). During a double<br />
division (meiosis), each mother cell forms a tetrad<br />
<strong>of</strong> 4 1n (haploid) microspores (f), which develop into 4<br />
pollen grains (male gametophytes).<br />
Pollen Grain<br />
In each pollen grain (g), nuclear division (mitosis) produces<br />
a large 1n vegetative nucleus (h) and a smaller<br />
1n generative nucleus (i), which divides to form two 1n<br />
sperm nuclei, usually after the pollen grain germinates<br />
to form a pollen tube (see 37).<br />
Mature Stamen<br />
Depending on the stamen type, the anther wall (j) spontaneously<br />
opens (dehisces) at a slit (k) to liberate pollen<br />
(l), or the anther wall breaks down, releasing pollen, or<br />
a portion <strong>of</strong> the anther lobe separates, leaving a pore<br />
(poricidal dehiscence).<br />
Pollen Grain Types<br />
Pollen grains have one or more furrows (m) or thin strips<br />
where the pollen tube may emerge. In some pollen<br />
grains, the pollen tube may emerge from a pore in the<br />
furrow or a pore not associat<strong>ed</strong> with a furrow.<br />
In flowering plants, the main types <strong>of</strong> pollen grains (n)<br />
are uniaperaturate with one furrow and triaperaturate<br />
with 3 furrows. Monocots and some primitive dicots<br />
have uniaperaturate pollen grains. Most dicots have<br />
triaperaturate pollen grains. Pollen grains vary from<br />
species to species in size, shape, and decoration <strong>of</strong><br />
the outer wall (exine). Some pollen grains lack an exine.<br />
The study <strong>of</strong> pollen grains <strong>of</strong> past and present-day<br />
plants is call<strong>ed</strong> palynology.<br />
31<br />
COLOR CODE<br />
white: filament (a), microspore mother cell (e),<br />
microspore (f), anther wall (j)<br />
light green: anther pollen sacs (c)<br />
orange: tapetum (d), vegetative nucleus (h),<br />
generative nucleus (i)<br />
yellow: pollen grains (g, l, m,n)
Flower—Ovule Development<br />
Young Pistil<br />
When flowering is initiat<strong>ed</strong>, the pistil begins to develop<br />
in the center <strong>of</strong> the flower. It consists <strong>of</strong> stigma (at top),<br />
style and ovary (at base). The ovary (a) <strong>of</strong> the pistil<br />
has one or more separate or fus<strong>ed</strong> carpels (b). Within<br />
the carpel are locules (c) where ovules (d) develop.<br />
Ovule development begins with meiosis in a 2n megaspore<br />
mother cell (e) within the center portion <strong>of</strong> a young<br />
ovule (megasporangium). The megaspore mother cell<br />
undergoes a double r<strong>ed</strong>uction/division (meiosis) to form<br />
a linear tetrad <strong>of</strong> 1n megaspores. Of these, usually<br />
3 abort (f) with one megaspore (g) remaining.<br />
Embryo Sac<br />
The nucleus <strong>of</strong> the remaining megaspore divides repeat<strong>ed</strong>ly<br />
(mitosis) to form the 8 haploid (1n) nuclei <strong>of</strong><br />
the embryo sac (female gametophyte, h). The central<br />
part <strong>of</strong> the ovule is vegetative tissue, nucellus (i). Surrounding<br />
the embryo sac are one or two layers <strong>of</strong> cells,<br />
the integuments (j), with a small opening at the base<br />
call<strong>ed</strong> the micropyle (k).<br />
Mature Ovule<br />
The 3 nuclei <strong>of</strong> most embryo sacs align into positions<br />
so that 1 near the micropylar end is the egg cell (l),<br />
2 are nuclei <strong>of</strong> synergid cells (m) with associat<strong>ed</strong> filiform<br />
apparatus (n), 2 are polar nuclei (o), and 3 are nuclei<br />
<strong>of</strong> antipodal cells (p). The mature ovule within the pistil<br />
consists <strong>of</strong> the embryo sac (h) surround<strong>ed</strong> by nucellus<br />
(i) and integuments (j). It is attach<strong>ed</strong> to the placenta (q)<br />
by a stalk call<strong>ed</strong> the funiculus (r).<br />
32<br />
COLOR CODE<br />
light green: ovary (a), integuments (j) placenta (q),<br />
funiculus (r)<br />
white: carpel (b), locule (c), ovule (d), abort<strong>ed</strong><br />
megaspores (f), synergids (m) filiform<br />
apparatus (n) polar nuclei (o), antipodals<br />
(p)<br />
gray: mother cell (e) megaspore (g), embryo<br />
sac (h)<br />
tan: egg (l)<br />
orange: nucellus (i)
Flower Pollination by Insects<br />
The transfer <strong>of</strong> pollen from an anther to the stigma<br />
<strong>of</strong> a pistil is call<strong>ed</strong> pollination. Some flowers are<br />
self-fertile and self-pollinat<strong>ed</strong>. Cross-pollination takes<br />
place when pollen is transferr<strong>ed</strong> to another plant. This<br />
provides genetic diversity. Within flowers <strong>of</strong> an individual<br />
plant, the time <strong>of</strong> pollen and stigma maturity may<br />
not coincide. Thus, all the pollen may be sh<strong>ed</strong> before<br />
the stigma matures and pollen must be transferr<strong>ed</strong> from<br />
another plant for fertilization to take place.<br />
Insect Pollination<br />
Although primitive se<strong>ed</strong> plants, such as conifers, are<br />
wind-pollinat<strong>ed</strong>, fossil evidence shows that when flowering<br />
plants appear<strong>ed</strong>, primitive insects such as beetles<br />
pollinat<strong>ed</strong> them. Beetles have biting mouthparts,<br />
and pollination <strong>of</strong> primitive flowers involv<strong>ed</strong> devouring<br />
pollen and other floral parts. Flowering plants develop<strong>ed</strong><br />
structures that attract<strong>ed</strong> other types <strong>of</strong> insects. As<br />
flowering plants diversifi<strong>ed</strong>, there was a parallel diversity<br />
<strong>of</strong> insect specializations. Insects develop<strong>ed</strong> various<br />
mouthpieces, some in the form <strong>of</strong> hollow tubes (probosci).<br />
Nectar. In some plants, nectar (a sugar-water solution)<br />
was secret<strong>ed</strong>. Then, conceal<strong>ed</strong> nectar at the bases <strong>of</strong><br />
petal, stamens, or ovaries appear<strong>ed</strong> in some plants.<br />
Some plants develop<strong>ed</strong> unisexual flowers (see 28) secreting<br />
nectar, although most flowers pollinat<strong>ed</strong> by insects<br />
are bisexual (see 28). Some flowers develop<strong>ed</strong><br />
long nectar tubes or spurs (see 115, j), that attract insects<br />
with long probosci such as moths and butterflies.<br />
Petals. Many flowers secrete a strong scent. Scent<br />
produc<strong>ed</strong> in the petals differs among types <strong>of</strong> plants. In<br />
contrast to a green background, other colors appear<strong>ed</strong><br />
in flower petals. Some flowers, such as Iris, develop<strong>ed</strong><br />
lines or hairs on petals (see 129, g) direct<strong>ed</strong> toward the<br />
nectar glands (see 101, k). These are commonly call<strong>ed</strong><br />
nectar guides (see 130, n).<br />
33<br />
Specific insects were attract<strong>ed</strong> to plants that develop<strong>ed</strong><br />
corolla structures in the form <strong>of</strong> “landing platforms”<br />
(see 113, d), “overnight traps” (as in some arum family,<br />
Araceae, plants), and those that mimic the shape,<br />
scent, and color <strong>of</strong> female insects, a common strategy<br />
in the orchid family (Orchidaceae).<br />
Sepals. Some plant flowers develop<strong>ed</strong> stout sepals<br />
with overlapping bracts around the ovary. This is apparent<br />
in the arum family (see 127).<br />
Stamen. Plants produc<strong>ed</strong> pollen grains with a sticky<br />
coating and also the capacity to produce excessive<br />
pollen as food to lure pollinating insects. Some flowers<br />
develop<strong>ed</strong> fertile and sterile pollen on separate anthers<br />
to prevent wasteful expenditure <strong>of</strong> resources.<br />
Pistil. As plants diversifi<strong>ed</strong>, there was a change in<br />
ovary position from an expos<strong>ed</strong> superior position to one<br />
lower or below other floral parts (inferior ovary) (see 28).<br />
Pistils with inferior ovaries may have long styles, which<br />
elevate the stigma (see 113, sage flower).<br />
Butterfly-pollinat<strong>ed</strong> Flowers<br />
Butterflies are attract<strong>ed</strong> to flowers aggregat<strong>ed</strong> in a head<br />
<strong>of</strong> many small flowers. The butterfly tongue is a long<br />
coil<strong>ed</strong> tube adapt<strong>ed</strong> to sucking nectar from long-tub<strong>ed</strong><br />
flowers. Pollen is dust<strong>ed</strong> on the tongue and head <strong>of</strong> the<br />
butterfly. The flickering appearance <strong>of</strong> flowers shaken<br />
by the wind is associat<strong>ed</strong> with the presence <strong>of</strong> nectar to<br />
butterflies. Flowers attractive to butterflies have sweet<br />
scents and are usually blue, dark pink, yellow-r<strong>ed</strong>,<br />
and purple. The illustrat<strong>ed</strong> example is r<strong>ed</strong> clover (Trifolium<br />
pratense) with a female black swallowtail butterfly<br />
(Papilio polyxenes asterius).<br />
COLOR CODE<br />
white: sepal ribs (a), petal tube (f)<br />
pale green: leaflet center (b)<br />
green: p<strong>ed</strong>uncle (c), leaflets (d), sepals (e)<br />
pink-purple: petal lobes (g)<br />
yellow: spots on abdomen (h), rows <strong>of</strong> outer<br />
forewing spots (i), row <strong>of</strong> outer hindwing<br />
cresents (j)<br />
orange: row <strong>of</strong> inner forewing spots (k), row <strong>of</strong><br />
inner hindwing spots (l), single spot (m),<br />
row <strong>of</strong> spots between j and m<br />
blue: row <strong>of</strong> mut<strong>ed</strong> areas across hindwing (n)
Flower Pollination by Insects<br />
(continu<strong>ed</strong>)<br />
Bee-pollinat<strong>ed</strong> Flowers<br />
Bees perceive flowers that reflect yellow-green, bluegreen,<br />
blue-violet, and ultraviolet light. Petals <strong>of</strong> flowers<br />
with color<strong>ed</strong> lines or dark marks guide bees toward<br />
nectaries. Rows <strong>of</strong> dots, stripes, crosses, and checks<br />
on flowers attract bees.<br />
The most common type <strong>of</strong> bee-pollinat<strong>ed</strong> flower has<br />
a “landing platform” such as the two-lipp<strong>ed</strong> (bilabiate)<br />
petals found in the flowers <strong>of</strong> the mint family (see 113,<br />
Lamiaceae), or falsely two-lipp<strong>ed</strong> petals such as the<br />
fus<strong>ed</strong> petals <strong>of</strong> banners and keel found in the pea family<br />
(see 100, Fabaceae).<br />
Bee-pollinat<strong>ed</strong> flowers have light, sweet, pleasant<br />
scents. Bees collect pollen (as a protein source to fe<strong>ed</strong><br />
larvae) as well as sugar-rich nectar, which is convert<strong>ed</strong><br />
to the honey on which they fe<strong>ed</strong>. Honeybees have a<br />
so-call<strong>ed</strong> pollen basket. Their bristly hairs attract pollen<br />
grains that they then brush with their legs into the basket<br />
on either side <strong>of</strong> their bodies. When baskets are tightly<br />
pack<strong>ed</strong> with pollen, they return to the hive. Of course,<br />
not all <strong>of</strong> the pollen is collect<strong>ed</strong>; much is brush<strong>ed</strong> <strong>of</strong>f on<br />
the next flower visit<strong>ed</strong> insuring pollination.<br />
Bees are the most efficient insect pollinators, as they<br />
will visit every flower in a mass <strong>of</strong> plants until the nectar<br />
is exhaust<strong>ed</strong>. Some flowers secrete nectar only at a<br />
specific time <strong>of</strong> day when fertilization is to take place;<br />
consequently, bees visit these flowers only at that time.<br />
Some flowers contain nectar in long spurs and are visit<strong>ed</strong><br />
by long-tongu<strong>ed</strong> bees (see 115, Linaria).<br />
For an illustrat<strong>ed</strong> example, see iris family (120, Iridaceae),<br />
flag (Iris) with a bumblebee (Bombus affinis).<br />
34<br />
Moth-pollinat<strong>ed</strong> Flowers<br />
Highly scent<strong>ed</strong> and white, green, or yellow flowers are<br />
attractive to moths. Night-flying (nocturnal) moths pollinate<br />
night-blooming flowers. Nectar at the base <strong>of</strong><br />
long petal tubes (a) is available only to insects such<br />
as moths with very long tubular mouth parts (f). Many<br />
moth-pollinat<strong>ed</strong> flowers are star-shap<strong>ed</strong> with a central<br />
funnel to the nectary.<br />
The illustrat<strong>ed</strong> example is a tobacco flower (Nicotiana)<br />
with a Carolina sphinx moth (Protoparce sexta).<br />
(Moth adapt<strong>ed</strong> with permission from the National Geographic).<br />
Fly-pollinat<strong>ed</strong> Flowers<br />
Many flowers pollinat<strong>ed</strong> by flies have expos<strong>ed</strong> nectar.<br />
Some have sweet odors, and other flowers have odor<br />
and color (pink, purple, green) <strong>of</strong> decomposing organic<br />
matter, which attracts flies. Usually flies are attract<strong>ed</strong> to<br />
white, yellow, and yellow-green flowers.<br />
In the arum family (see 127, Araceae), the odor and<br />
color <strong>of</strong> the flower cluster (spadix), with its bract<br />
(spathe, n) attract flies. In some species, a fly visitor<br />
slides down the spadix, is trapp<strong>ed</strong> in the spathe, and is<br />
releas<strong>ed</strong> within a day, carrying mature pollen.<br />
The illustrat<strong>ed</strong> example is a skunk cabbage (Symplocarpus<br />
foetidus) inflorescence with two syrphid carrion<br />
flies (Allograpta obliqua).<br />
COLOR CODE<br />
white: petal tube (a), fly wings (i), spadix<br />
flowers (p)<br />
yellow: stamens (b, o)<br />
green: calyx (c), p<strong>ed</strong>uncle (d), fly thorax (k),<br />
lines on spathe (m)<br />
light gray: moth eyes (e), moth tongue (f), moth<br />
thorax (g), moth wings (h)<br />
tan: fly eyes (j)<br />
orange: fly abdomen (l)<br />
purple: spathe (n)
Flower Pollination by Wind<br />
Wind Pollination<br />
From the fossil record, we learn that wind pollination<br />
was a later development in flowering plants. To change<br />
from pollination by insects to pollen transferr<strong>ed</strong> by wind<br />
currents, loss <strong>of</strong> color, petals, nectaries, scent, and the<br />
sticky covering on pollen grains became apparent. With<br />
the exception <strong>of</strong> sexual structures, flower parts develop<strong>ed</strong><br />
that were much smaller in size.<br />
The stamens increas<strong>ed</strong> in size and number, and some<br />
stamens develop<strong>ed</strong> very long filaments. Huge amounts<br />
<strong>of</strong> tiny, dry pollen grains develop<strong>ed</strong>. Since wind is a<br />
chance pollinator, that is, more is better. The stigma<br />
<strong>of</strong> the pistil increas<strong>ed</strong> in size and <strong>of</strong>ten became feathery<br />
(plumose) or divid<strong>ed</strong>. The number <strong>of</strong> carpels in the<br />
ovary also increas<strong>ed</strong> in some flowers.<br />
Bisexual flowers chang<strong>ed</strong> to separate staminate (male)<br />
and pistillate (female) unisexual flowers and increas<strong>ed</strong><br />
in number. Unisexual flowers tend<strong>ed</strong> to aggregate in<br />
clusters or to form catkins (aments). In some dicots,<br />
staminate and pistillate flowers form<strong>ed</strong> on separate<br />
plants (dioecious) (see 106, staghorn sumac).<br />
Wind-pollinat<strong>ed</strong> Flowers<br />
Some <strong>of</strong> the monocot herbs that are wind-pollinat<strong>ed</strong><br />
are members <strong>of</strong> the grass (Poaceae, see 123), cattail<br />
(Typhaceae), and rush (Juncaceae) families. Bisexual<br />
or staminate unisexual flowers are elevat<strong>ed</strong> on slender<br />
stalks above the vegetative parts <strong>of</strong> the plant.<br />
35<br />
Wind pollination is also found in trees, such as elms,<br />
ashes, and hackberries <strong>of</strong> the elm family (see 82, Ulmaceae).<br />
Birches, ironwoods, alders, and hazelnuts <strong>of</strong><br />
the birch family (see 84, Betulaceae), beeches, oaks,<br />
and chestnuts <strong>of</strong> the beech family (see 83, Fagaceae)<br />
and poplars <strong>of</strong> the willow family (see 95, Salicaceae)<br />
are also trees with wind pollination.<br />
The notorious ragwe<strong>ed</strong> (Ambrosia) in the aster family<br />
(Asteraceae, see 119) is an obvious herbaceous dicot<br />
example. Hayfever sufferers are familiar with its windblown<br />
pollen.<br />
Willows (Salix spp.) have unisexual r<strong>ed</strong>uc<strong>ed</strong> flowers<br />
in catkins but have nectar glands and are insectpollinat<strong>ed</strong>.<br />
Staminate flowers, which form in clusters,<br />
swing loosely on an axis and open during the windy<br />
spring period before the leaves expand. Vestiges <strong>of</strong> bisexual<br />
flowers remain in some wind-pollinat<strong>ed</strong> flowers<br />
that have r<strong>ed</strong>uc<strong>ed</strong>, sterile structures <strong>of</strong> the opposite sex<br />
(see 105, maple family, Aceraceae).<br />
The illustrat<strong>ed</strong> example is a box elder (Acer negundo),<br />
which is dioecious. The flower in a cluster <strong>of</strong> staminate<br />
(male) flowers has pendant anthers (b) on a long p<strong>ed</strong>icel<br />
(c). On a tree with pistillate (female) flowers, the<br />
compound leaves (I) begin to expand as the flower develop.<br />
The pistillate flowers has fus<strong>ed</strong>, lob<strong>ed</strong> sepals (j),<br />
a double ovary (k) and divid<strong>ed</strong> stigmas(l).<br />
COLOR CODE<br />
tan: leaf scars (a, f)<br />
yellow: anthers (b)<br />
yellow-green: p<strong>ed</strong>icel (c), shoots (d, g), bud scales<br />
(e, h), leaflet (i), sepals (j)<br />
tan-green: ovaries (k)<br />
white: stigmas (l)
Flower Pollination by Birds and Bats<br />
Bird and Bat Pollination<br />
A flower pollinat<strong>ed</strong> by birds or bats usually possesses<br />
both staminate (male) and pistillate (female) reproductive<br />
structures (bisexual). Some have sweet, fleshy<br />
bracts surrounding the flower as well as pollen and nectar.<br />
Others may have imitation pollen made <strong>of</strong> proteins<br />
and/or starch.<br />
While some flowers attract birds or bats, animals such<br />
as slugs, snails, earthworms, mice, rats, squirrels and<br />
opossums pollinate other flowers. Gerbils, mice and<br />
shrews pollinate various South African Protea species.<br />
These plants produce low-lying flowers <strong>of</strong> dull colors.<br />
The attraction for animals is food, i. e., copious amounts<br />
<strong>of</strong> nectar that contains not only sugar, but vitamins,<br />
amino acids and other nutrients. While an animal<br />
is gathering nectar, pollen grains with hooks and<br />
spines and sticky coatings adhere to the animal’s<br />
coat to be transferr<strong>ed</strong> to another flower resulting in<br />
pollination.<br />
Bird-pollinat<strong>ed</strong> Flowers<br />
Birds pollinate many tropical and subtropical plants.<br />
Flowers attractive to birds are usually bright r<strong>ed</strong><br />
or orange. Some have striking color contrasts.<br />
Hummingbird-pollinat<strong>ed</strong> flowers are mainly r<strong>ed</strong>, a color<br />
not usually perceiv<strong>ed</strong> by insects. Bird-pollinat<strong>ed</strong> flowers<br />
have abundant nectar and are without scent. Some are<br />
tube flowers with a basal swelling fill<strong>ed</strong> with nectar. The<br />
ovaries may be inferior or separat<strong>ed</strong> from the nectaries,<br />
36<br />
as in spur flowers, so that damage does not incur while<br />
the pollinator is visiting.<br />
Some bird visitors fe<strong>ed</strong> on small insects attract<strong>ed</strong><br />
by the nectar. Some bird-pollinat<strong>ed</strong> flowers are very<br />
large, while others are small. Some plants have sturdy<br />
perches near flowers, while others have freely swinging<br />
flowers, which attract hovering birds.<br />
Generally, bird-pollinat<strong>ed</strong> flower forms are <strong>of</strong> the twolipp<strong>ed</strong><br />
(bilabiate) type, tubular flowers, flowers with a<br />
protruding bottlebrush stamen arrangement, or flowers<br />
with nectar in spurs.<br />
The illustration example is fuchsia (Fuchsia magellanica)<br />
with a Brazilian hermit hummingbird (Phaethornis<br />
eurynoma).<br />
Bat-pollinat<strong>ed</strong> Flowers<br />
Bats pollinate many large tropical herbs and trees.<br />
These flowers are usually arrang<strong>ed</strong> in a manner easily<br />
accessible to flying bats. Flowers attractive to bats<br />
bloom at night, have large amounts <strong>of</strong> nectar and pollen,<br />
are usually pale in color, may have a musky or fruity<br />
odor, and are strong enough to support a bat. Batpollinat<strong>ed</strong><br />
flowers are bell-shap<strong>ed</strong>, open saucer-shap<strong>ed</strong><br />
with many stamens, or possess suspend<strong>ed</strong> flowers with<br />
stamens bunch<strong>ed</strong> in a protruding brush.<br />
The illustration example is a saguaro cactus (Carnegiea<br />
gigantea) flower with a long-nos<strong>ed</strong> bat (Leptonycteris<br />
sanborni).<br />
COLOR CODE<br />
green: p<strong>ed</strong>uncle (a), ovary (b)<br />
r<strong>ed</strong>: sepals (c ), filaments (f), style (h), bat<br />
tongue<br />
r<strong>ed</strong>-purple: petals (d)<br />
yellow: anthers (e), stigma (g), pollen(l),<br />
spines (p)<br />
yellow-green: bracts (o)<br />
light orange: area below bird’s eye (i), breast<br />
feathers (j), tips <strong>of</strong> bracts (n)<br />
white: unshad<strong>ed</strong> areas <strong>of</strong> tail, near tail (k),<br />
tepals (m)<br />
light brown: remaining bird feathers, not color<strong>ed</strong><br />
above<br />
brown-orange: entire bat, except tongue and pollen
Flower—Fertilization and Embryo Development<br />
Fertilization<br />
Pistil. During pollination, pollen (a) from a stamen is<br />
transferr<strong>ed</strong> to a stigma (b). The stigmatic surface is usually<br />
cover<strong>ed</strong> with secretory cells (c) possessing copious<br />
amounts <strong>of</strong> sugars ne<strong>ed</strong><strong>ed</strong> for growth <strong>of</strong> the pollen<br />
tube (d). The pollen tube grows within the style (e) to<br />
the ovule (f) in the ovary (g). There, it enters the embryo<br />
sac (h) at the opening (micropyle) between the<br />
integuments (i). Within the pollen tube are the 1n (haploid)<br />
tube nucleus (j) and two 1n (haploid) sperm nuclei<br />
(k, l). After entry into the embryo sac, the pollen tube tip<br />
bursts and discharges the 2 sperm nuclei. Simultaneously,<br />
one or both synergid cells (m) disintegrate (see<br />
32).<br />
Embryo Sac. Within the embryo sac double fertilization<br />
occurs. The egg (n) nucleus (o) fuses with one<br />
sperm nucleus (k) to form a 2n (diploid) zygote (q). The<br />
other sperm nucleus (l) unites with the 2 polar nuclei (p)<br />
to form a 3n (triploid) primary endosperm nucleus (r).<br />
Embryo Development<br />
Globular Stage Embryo. The primary endosperm nucleus<br />
divides repeat<strong>ed</strong>ly to form many 3n free, floating<br />
nuclei (s). Meanwhile, the zygote starts to divide, forming<br />
a basal cell (t), which develops into a suspensor<br />
(u) to elevate the developing embryo in the sac and<br />
to transport nutrients. An apical cell divides to form a<br />
globular mass <strong>of</strong> cells (v).<br />
Heart Stage Embryo. Walls develop around the free<br />
endosperm nuclei, forming the cellular endosperm (w).<br />
The endosperm cells contain stor<strong>ed</strong> food reserves such<br />
as hormones, starch, proteins, oils, and fats. In dicots,<br />
the embryo becomes heart-shap<strong>ed</strong> with the formation<br />
<strong>of</strong> cotyl<strong>ed</strong>on primordia (x).<br />
Torp<strong>ed</strong>o Stage Embryo. As the young embryo elongates,<br />
the vascular systems for the young root (y) and<br />
shoot (z) are form<strong>ed</strong>.<br />
Mature Se<strong>ed</strong><br />
In the mature se<strong>ed</strong>, the integuments (i) <strong>of</strong> the embryo<br />
sac have develop<strong>ed</strong> into the protective se<strong>ed</strong><br />
coat (testa). The embryo illustrat<strong>ed</strong> has 2 se<strong>ed</strong> leaves<br />
(cotyl<strong>ed</strong>ons, x) <strong>of</strong> a dicot. (Monocots usually have 1<br />
se<strong>ed</strong> leaf or cotyl<strong>ed</strong>on, see 40, corn se<strong>ed</strong>)<br />
37<br />
COLOR CODE<br />
yellow: pollen (a), pollen tube (d), tube nucleus<br />
(j)<br />
light green: stigma (b), secretory cells (c), style (e),<br />
ovule (f), ovary (g), integuments (i)<br />
gray: embyo sac (h)<br />
white: synergids (m), polar nuclei (p), zygote<br />
(q), embryo (t, u, v, x, y, z)<br />
tan: egg (n)<br />
r<strong>ed</strong>: sperm nuclei (k, l), egg nucleus (o)<br />
orange: endosperm (r, s, w)
Fruit—Dry Types<br />
A fruit is the se<strong>ed</strong>-bearing structure in flowering plants<br />
(conifer se<strong>ed</strong>s are borne in a cone).<br />
Indehiscent, Dry Fruit Types<br />
An indehiscent, dry fruit does not open at maturity.<br />
The tissues are compos<strong>ed</strong> <strong>of</strong> parenchyma and/or sclerenchyma<br />
(see 8) at maturity.<br />
Achene. An achene (a) is a type <strong>of</strong> one-se<strong>ed</strong><strong>ed</strong> fruit<br />
with a thin wall (pericarp).<br />
Grain (Caryopsis). A grain (c) is a type <strong>of</strong> achene found<br />
in grasses (see 123, grass family, Poaceae), which originates<br />
from a superior ovary (see 28).<br />
Cypsela. An achene that originates from an inferior<br />
ovary, and commonly has a hairy pappus (d) present,<br />
is a cypsela (e).<br />
Nut. An achene-type fruit, the nut (f) is hard and “bony,”<br />
and may result from a compound ovary.<br />
Samara. The samara is a type <strong>of</strong> wing<strong>ed</strong> achene,<br />
which may be single, as in elm (Ulmus, h), or double,<br />
as in maple (Acer, i).<br />
Schizocarp. Carpels <strong>of</strong> a compound ovary break apart<br />
into mericarps (j), which function as achenes in the<br />
schizocarp type fruit.<br />
38<br />
Nutlet. A small nut is call<strong>ed</strong> a nutlet (k).<br />
Dehiscent, Dry Fruit Types<br />
A dehiscent, dry fruit opens to release se<strong>ed</strong>s at maturity.<br />
The fruit splits under tension along definite lines or<br />
breakage points.<br />
Follicle. Compos<strong>ed</strong> <strong>of</strong> a single pistil, the follicle (l) splits<br />
along one line (see 77, Magnolia grandiflora).<br />
Legume. A legume (m) originates from one carpel,<br />
which splits along two lines, and is the fruit type <strong>of</strong> the<br />
pea family (see 100, Fabaceae). A type <strong>of</strong> legume,<br />
the se<strong>ed</strong>s <strong>of</strong> a loment (n) are partition<strong>ed</strong> into sections.<br />
The carpel <strong>of</strong> a spiral legume (o) coils.<br />
Capsule. Capsules have more than one carpel and<br />
are classifi<strong>ed</strong> by the mode <strong>of</strong> opening (dehiscence).<br />
The septicidal capsule (p) opens in the plane <strong>of</strong> carpel<br />
union. A loculicidal capsule (r) opens around a horizontal<br />
line. A poricidal capsule (t) releases se<strong>ed</strong>s<br />
through pores at the top.<br />
Silique. A silique has 2 narrow pieces (valves,u) separat<strong>ed</strong><br />
by a partition (replum, v). A round<strong>ed</strong> form is<br />
call<strong>ed</strong> a silicle (w, x). These are fruits <strong>of</strong> the mustard<br />
family (see 96, Brassicaceae).<br />
COLOR CODE<br />
tan: achene (a), cypsela (e), nut (f),<br />
schizocarp mericarps (j), nutlets (k),<br />
spiral (o), septicidal capsule (p), se<strong>ed</strong>s<br />
(s), valve (x)<br />
white: grain (c), pappus (d), replum (v, w)<br />
r<strong>ed</strong>-brown: bracts (b)<br />
brown: cup (g), legume (m), loculicidal capsule<br />
(q), se<strong>ed</strong>s (y)<br />
yellow-tan: single samara (h)<br />
green: double samara (i), circumscissile<br />
capsule (r), valve (u)<br />
yellow: follicle (l), loment (n), poricidal capsule (t)
Fruit—Fleshy Types, Compound<br />
Fleshy Fruit Types<br />
The ovary or fruit wall (pericarp) consists <strong>of</strong> an outer<br />
layer (exocarp), middle layers <strong>of</strong> parenchyma (mesocarp),<br />
and an inner layer (endocarp). The parenchyma<br />
tissues are fill<strong>ed</strong> with sugars, starch, and/or fats at maturity.<br />
Berry. The entire pericarp (b, c) <strong>of</strong> a berry is fleshy.<br />
There may be one or more carpels and se<strong>ed</strong>s (d).<br />
Pepo. This berry with a hard-rind pericarp compos<strong>ed</strong><br />
<strong>of</strong> exocarp (e) and endocarp is a pepo fruit. It is deriv<strong>ed</strong><br />
from an inferior ovary (see gourd family, Cucurbitaceae,<br />
94).<br />
Hesperidium. A leathery-rind<strong>ed</strong> berry, the hesperidium<br />
exocarp (h) <strong>of</strong> compact collenchyma contains oil<br />
glands. There is a spongy mesocarp (i) and an endocarp<br />
(j), which produces juice sacs. This type, commonly<br />
call<strong>ed</strong> citrus, is found in the rue family, Rutaceae<br />
(see 107).<br />
Drupe. The drupe fruit ovary wall develops into a fleshy<br />
mesocarp (n) and a stony endocarp (o) over usually one<br />
se<strong>ed</strong>.<br />
Pome. A pome has a pericarp <strong>of</strong> cartilaginous endocarp<br />
(r) lining the se<strong>ed</strong> (q) cavities (locules), which are<br />
surround<strong>ed</strong> by fleshy parenchyma exocarp (s). Outside<br />
the inferior ovary wall is an expand<strong>ed</strong> floral tube (t) <strong>of</strong><br />
fleshy parenchyma. (For flower to fruit development,<br />
see rose family, Rosaeae, 99).<br />
Compound Fruit<br />
Aggregate Fruits. The separate carpel <strong>of</strong> one flower<br />
stays together as a unit in an aggregate fruit. Examples<br />
are an aggregate <strong>of</strong> drupelets (x), as in black raspberry<br />
fruits, an aggregate <strong>of</strong> achenes, as in strawberry fruits,<br />
and an aggregate <strong>of</strong> follicles (see 77, Magnolia grandiflora).<br />
Multiple Fruits. The carpels <strong>of</strong> separate flowers in a<br />
cluster stay together as a unit in multiple fruits as in a<br />
multiple <strong>of</strong> achenes in osage-orange and pineapple.<br />
39<br />
COLOR CODE<br />
tan: p<strong>ed</strong>icel (a), p<strong>ed</strong>uncle (l, p), se<strong>ed</strong> (d, k,<br />
y), endocarp (o)<br />
purple: exocarp (b)<br />
white: mesocarp (c, f, i, z), se<strong>ed</strong> (g), exocarp<br />
(s), floral tube (t)<br />
green: exocarp (e), p<strong>ed</strong>uncle (v), sepal (w)<br />
yellow: exocarp (h)<br />
pale yellow: endocarp (j, r)<br />
r<strong>ed</strong>: exocarp (m), mesocarp (n), epidermis<br />
(u)<br />
brown: se<strong>ed</strong> (q)<br />
dark blue: drupelet exocarp (x)<br />
yellow-green: epidermis (y)
Se<strong>ed</strong> Structure and Germination<br />
A se<strong>ed</strong>, which develops from an ovule, consists <strong>of</strong> a partially<br />
develop<strong>ed</strong> sporophyte plant (embryo) and none or<br />
various amounts <strong>of</strong> food storage tissue (endosperm)<br />
cover<strong>ed</strong> by a protective se<strong>ed</strong> coat (testa).<br />
Dicot Se<strong>ed</strong><br />
The embryo usually has two se<strong>ed</strong> leaves (cotyl<strong>ed</strong>ons).<br />
As the bean se<strong>ed</strong> is split in half, only one cotyl<strong>ed</strong>on<br />
(a) is shown. In the bean and pea se<strong>ed</strong>lings, two cotyl<strong>ed</strong>ons<br />
(a, b) can be seen. Between the cotyl<strong>ed</strong>ons is the<br />
hypocotyl axis (c) with the shoot meristem (epicotyl) at<br />
one end, the root meristem at the other end. An undevelop<strong>ed</strong><br />
root (radicle, d) may be present. The plumule<br />
(e) <strong>of</strong> the bean se<strong>ed</strong> will develop into stem (f) and leaves<br />
(g) in the se<strong>ed</strong>ling.<br />
Nutritive/food storage tissue (endosperm) sustains the<br />
germinating embryo until roots and leaves are functionally<br />
develop<strong>ed</strong>. Endosperm cells contain mostly starch<br />
with lesser amounts <strong>of</strong> proteins, oils, and/or fats. In bean<br />
se<strong>ed</strong>s, the cotyl<strong>ed</strong>ons, which occupy most <strong>of</strong> the space,<br />
store the food reserves, with the scant endosperm consisting<br />
mostly <strong>of</strong> protein.<br />
The se<strong>ed</strong> coat (h) is made up <strong>of</strong> the ovules’ fus<strong>ed</strong> integuments.<br />
An opening (micropyle) between the integuments<br />
sometimes leaves a pore (i). Where the ovule<br />
was attach<strong>ed</strong> to the placenta, by a stalk (funiculus),<br />
there is sometimes a scar (hilium, j). Usually the se<strong>ed</strong><br />
coat is very thick and may be color<strong>ed</strong>.<br />
Monocot Se<strong>ed</strong><br />
Usually monocot se<strong>ed</strong>s have one cotyl<strong>ed</strong>on. A grain<br />
fruit (caryopsis) is us<strong>ed</strong> as a monocot example. The<br />
embryo includes one cotyl<strong>ed</strong>on call<strong>ed</strong> the scutellum<br />
(k), an outer protective cylindrical leaf (coleoptile, l),<br />
which encloses young leaves (m) over the shoot apical<br />
meristem (n), and a protective cap (coleorhiza,o)over<br />
the root apex (p).<br />
40<br />
The outermost layer <strong>of</strong> the endosperm, the aleurone<br />
(q), contains most <strong>of</strong> the protein <strong>of</strong> the se<strong>ed</strong>, while the<br />
remaining endosperm (r) is mostly starch. In grains, the<br />
fruit coat (s) is made up <strong>of</strong> fus<strong>ed</strong> integuments and pericarp.<br />
In the monocot grain <strong>of</strong> rice (Oryza sativa), white rice<br />
(polish<strong>ed</strong> rice) is devoid <strong>of</strong> aleurone (“protein jacket”)<br />
and consists <strong>of</strong> embryo and starchy endosperm only.<br />
In contrast, brown rice (not polish<strong>ed</strong>) has the aleurone<br />
present and is thus much better nutritionally because<br />
the aleurone layer contains the bulk <strong>of</strong> the se<strong>ed</strong> storage<br />
proteins (6 to 12 % <strong>of</strong> dry weight). White rice is primarily<br />
starch.<br />
Conifer Se<strong>ed</strong><br />
The embryo axis (t) consists <strong>of</strong> cotyl<strong>ed</strong>ons (u) enclosing<br />
the shoot apical meristem at the tip, the hypocotyl,<br />
and the root apex (v) at the base. Conifer se<strong>ed</strong>s have<br />
no endosperm; the embryo is surround<strong>ed</strong> by megagametophyte<br />
tissue (w) and enclos<strong>ed</strong> by a se<strong>ed</strong> coat (x).<br />
Germination<br />
Se<strong>ed</strong> germination is the growth <strong>of</strong> the embryo, resulting<br />
in emergence <strong>of</strong> a shoot (epicotyl) and root<br />
(radicle). To germinate, the se<strong>ed</strong> must be alive, not dormant,<br />
have a suitable temperature, adequate moisture,<br />
an oxygen supply, and for some species, light.<br />
Once the radicle has emerg<strong>ed</strong> from the se<strong>ed</strong> coat,<br />
the se<strong>ed</strong>ling either develops with its cotyl<strong>ed</strong>ons above<br />
ground (epigeous), as in bean (a) and pine (u), or below<br />
ground (hypogeous), as in pea (b) and corn (s).<br />
The cotyl<strong>ed</strong>ons <strong>of</strong> epigeous se<strong>ed</strong>lings produce chloroplasts<br />
and function photosynthetically until true leaves<br />
develop. Cotyl<strong>ed</strong>ons <strong>of</strong> hypogeous se<strong>ed</strong>lings provide<br />
food for the developing plants.<br />
COLOR CODE<br />
Se<strong>ed</strong>s: white<br />
Se<strong>ed</strong>lings:<br />
green: cotyl<strong>ed</strong>ons (a, b, u), leaves and stipules<br />
(g), leaf (m), embryo axis (c, t), stem (f),<br />
coleoptile (l)<br />
tan: se<strong>ed</strong> coat (h, x)<br />
white: roots<br />
yellow: fruit coat (s)
Major Groups; Geologic Time Scale<br />
Learning about the relationships <strong>of</strong> plants to each other<br />
involves the study <strong>of</strong> plant fossils (paleobotany), physical<br />
characteristics (anatomy), form (morphology), inheritance<br />
(genetics), chemical characteristics (physiology<br />
and plant biochemistry), and plant communities<br />
(ecology).<br />
Carolus Linnaeus (1707–1778) organiz<strong>ed</strong> a system,<br />
that has since been expand<strong>ed</strong>, for the classification <strong>of</strong><br />
plants on the basis <strong>of</strong> their evolutionary relationships.<br />
Some groups <strong>of</strong> organisms studi<strong>ed</strong> by botanists are now<br />
no longer recogniz<strong>ed</strong> as plants, as for example, bacteria,<br />
blue-green algae, fungi, and lichens. They are studi<strong>ed</strong><br />
by specialists on bacteria and blue-greens (microbiologists),<br />
green, r<strong>ed</strong>, and brown algae (algologists),<br />
fungi (mycologists), and lichens (lichenologists).<br />
The Bacterial Group consists <strong>of</strong> bacteria, blue-greens<br />
and other microorganisms. In the past, blue-greens<br />
were group<strong>ed</strong> with algae. Now it is known that they are<br />
genetically more like bacteria. The cells <strong>of</strong> bacteria and<br />
blue-greens do not have organelles; instead, the cell<br />
membranes carry on many <strong>of</strong> the biological functions.<br />
There is no membrane-bound nucleus in the cell. This<br />
is term<strong>ed</strong> prokaryotic (pro = before, karyon = nucleus).<br />
Nuclear material consists <strong>of</strong> strands <strong>of</strong> DNA<br />
(deoxyribonucleic acid, a molecule that constitutes the<br />
genetic information <strong>of</strong> a cell). Fibrils <strong>of</strong> DNA in the central<br />
region <strong>of</strong> a bacterial cell are designat<strong>ed</strong> by the<br />
term nucleoid. Asexual reproduction occurs by cell division<br />
or budding. Sexual reproduction is a recombination<br />
<strong>of</strong> genetic material. Most are microorganisms, smaller<br />
than the eukaryotic cells (eu = true, karyon = cell) <strong>of</strong><br />
the other three kingdoms.<br />
Revision Group. Classification and relationships <strong>of</strong><br />
molds, mildews, rusts, chytrids and allies, din<strong>of</strong>lagellates,<br />
algal groups, and stoneworts and others are currently<br />
under revision.<br />
A characteristic in common in this group is the presence<br />
<strong>of</strong> nuclei (eukaryotic) in the cells. Many obtain food<br />
41<br />
(organic carbon metabolites) by photosynthesis within<br />
cell organelles call<strong>ed</strong> plastids. A flagellum (whip) for locomotion<br />
or fe<strong>ed</strong>ing is present in many members. Most<br />
require oxygen (aerobic). They are aquatic.<br />
Fungi are organisms with nucleat<strong>ed</strong> cells (eukaryotic),<br />
that form resistant fungal spores, have cell walls<br />
compos<strong>ed</strong> <strong>of</strong> chitin, and do not have mobile cells at any<br />
stage. Fungi are found from the fossil record 450–500<br />
million years ago (the Ordovician period).<br />
Representative divisions in this book are black bread<br />
mold and allies, sac fungi, and club fungi. Lichen classification<br />
is a problem because lichens are an association<br />
<strong>of</strong> either a blue-green or a green alga with either a<br />
sac fungus or a club fungus. Lichens are includ<strong>ed</strong> here<br />
with the fungi.<br />
Plants represent<strong>ed</strong> here include liverworts, hornworts,<br />
mosses, whisk ferns, clubmosses, spikemosses<br />
and quillworts, horsetails, ferns, and plants bearing<br />
se<strong>ed</strong>s. Se<strong>ed</strong>-bearing plants include the gymnosperms<br />
(= nak<strong>ed</strong> se<strong>ed</strong>s) and the angiosperms (= enclos<strong>ed</strong><br />
se<strong>ed</strong>s).<br />
Living gymnosperm groups are cycads, ginkgo,<br />
conifers, and gnetes. The angiosperm group consists<br />
<strong>of</strong> flowering plants. Characteristics <strong>of</strong> plants are cover<strong>ed</strong><br />
in all three sections <strong>of</strong> the book.<br />
Geologic Time Scale<br />
Eras. The largest units <strong>of</strong> geologic time are known as<br />
eras; each encompasses millions <strong>of</strong> years. They are<br />
basically defin<strong>ed</strong> by biological events – the appearance<br />
or disappearance <strong>of</strong> major groups <strong>of</strong> organisms. These<br />
changes in biology are relat<strong>ed</strong> to major geologic events.<br />
However, only the biologic changes are seen worldwide<br />
in the fossil record.<br />
Periods. Each era is subdivid<strong>ed</strong> into periods, and the<br />
periods are broken down into epochs; again their separations<br />
are most commonly bas<strong>ed</strong> on fossils.
Geologic Time Scale<br />
Era Period Life<br />
Precambrian<br />
Precambrian The first fossil organisms <strong>of</strong> bacteria and blue-greens are found in rocks<br />
over 3,000 million years old,<br />
The earliest eukaryotic cells (true nucleat<strong>ed</strong> cells) are found in rocks<br />
about 1,000 million years old. These fossils are rare.<br />
600 million years ago -----------------------------------------------------------------------<br />
Fossils <strong>of</strong> invertebrate marine animals are present.<br />
Paleozoic (Old Life)<br />
Cambrian<br />
500------------------------------------------------------------------------------------<br />
The oldest fossils <strong>of</strong> fungi are from 450 million years ago and algae fossils<br />
Ordovician<br />
are common. Din<strong>of</strong>lagellates are present.<br />
430------------------------------------------------------------------------------------<br />
Silurian Oldest fossils <strong>of</strong> land plants are present.<br />
400------------------------------------------------------------------------------------<br />
Land plants became abundant during the Devonian. Fossils <strong>of</strong><br />
Devonian clubmosses, spikemosses, quillworts, giant horsetails, scouring rushes<br />
and ferns are found in this period.<br />
345------------------------------------------------------------------------------------<br />
Mississippian<br />
During the Carboniferous (Mississippian and Pennsylvanian periods),<br />
310--------------------------there<br />
were vast forests <strong>of</strong> trees and swamps preserv<strong>ed</strong> now as coal.<br />
Pennsylvanian<br />
280------------------------------------------------------------------------------------<br />
During the Permian, gnetes were present and true conifers emerg<strong>ed</strong>.<br />
Permian<br />
Ginkgos also originat<strong>ed</strong> during this period.<br />
225------------------------------------------------------------------------------------<br />
Mesozoic (Middle Life)<br />
Triassic The Triassic was the time <strong>of</strong> reptiles and dinosaurs and the first mammals.<br />
There were forests <strong>of</strong> gymnosperms and ferns. Cycads were also present.<br />
180------------------------------------------------------------------------------------<br />
The Jurassic was the “age <strong>of</strong> cycads” and it was a time when conifers<br />
Jurassic were distribut<strong>ed</strong> worldwide. Birds originat<strong>ed</strong> during this period. Reptiles<br />
were also dominant.<br />
136------------------------------------------------------------------------------------<br />
Cretaceous Primitive flowering plants evolv<strong>ed</strong> during the Cretaceous.<br />
65------------------------------------------------------------------------------------<br />
Cenozoic (New Life)<br />
During the Tertiary, flowering plants dominat<strong>ed</strong> the land. Later, grasslands<br />
Tertiary were apparent. The landscape has been dominat<strong>ed</strong> by herbaceous<br />
flowering plants ever since.<br />
2.5------------------------------------------------------------------------------------<br />
Quaternary Humans are present.
Fossils<br />
Fossil Record and Appearance <strong>of</strong> Vascular Plants<br />
About 85% <strong>of</strong> earth’s geologic time is within the Precambrian.<br />
In the Precambrian, in rocks over 3,000 million<br />
years old, the first fossil organisms <strong>of</strong> bacteria and bluegreens<br />
are found. The earliest eukaryotic cells are from<br />
rocks about 1,000 million years old. These fossils are<br />
rare, and the early evolutionary history <strong>of</strong> non-vascular<br />
plants is obscure.<br />
The division that marks the end <strong>of</strong> Precambrian time<br />
and the beginning <strong>of</strong> the Paleozoic, about 600 million<br />
years ago, is recogniz<strong>ed</strong> by the worldwide appearance<br />
<strong>of</strong> fossils <strong>of</strong> invertebrate marine animals. In the late<br />
Silurian period, the first vascular plants appear. Vascular<br />
plants are so designat<strong>ed</strong> because they possess<br />
specializ<strong>ed</strong> conducting tissues <strong>of</strong> xylem and phloem<br />
(see 9).<br />
Land plants became abundant during the Devonian.<br />
During the Carboniferous (Mississippian and Pennsylvanian),<br />
there were vast forests <strong>of</strong> trees and swamps<br />
preserv<strong>ed</strong> as what we know as coal.<br />
The Jurassic time <strong>of</strong> the Mesozoic was the “age <strong>of</strong> cycads”<br />
and it was a time when conifers became distribut<strong>ed</strong><br />
worldwide.<br />
Primitive flowering plants evolv<strong>ed</strong> during the Cretaceous,<br />
and by the Tertiary time <strong>of</strong> the Cenozoic, they<br />
dominat<strong>ed</strong> the land. Later, grasslands were apparent<br />
and the landscape has been dominat<strong>ed</strong> by herbaceous<br />
flowering plants ever since.<br />
Fossil Evidence. A fossil represents evidence <strong>of</strong> past<br />
life. Fossils are usually found in nature as preserv<strong>ed</strong><br />
remains or they may be just an imprint <strong>of</strong> an organism<br />
or part <strong>of</strong> an organism. Usually, vascular plant fossils<br />
occur as fragments. They <strong>of</strong>ten show alteration <strong>of</strong> original<br />
structures through damage by transport away from<br />
where they liv<strong>ed</strong> and when rock deposits were form<strong>ed</strong>.<br />
During the process <strong>of</strong> fossil formation, plant parts commonly<br />
were compress<strong>ed</strong> in s<strong>of</strong>t s<strong>ed</strong>iment, which later<br />
harden<strong>ed</strong> into rock, leaving an imprint such as a fern<br />
leaf. Or the plant was emb<strong>ed</strong>d<strong>ed</strong> in a s<strong>of</strong>t matrix and<br />
later decay<strong>ed</strong> as the rock form<strong>ed</strong>, leaving a mold <strong>of</strong> its<br />
exterior. Or later, a hollow mold may have been fill<strong>ed</strong> in<br />
with mineral deposits forming a natural cast <strong>of</strong> the plant<br />
structure.<br />
42<br />
Emb<strong>ed</strong>d<strong>ed</strong>, “petrifi<strong>ed</strong>” plant fossils are a result <strong>of</strong> cell<br />
contents being replac<strong>ed</strong> by minerals while the cell walls<br />
are preserv<strong>ed</strong>. Thus, thinly cut sections reveal the microstructure<br />
<strong>of</strong> the fossiliz<strong>ed</strong> plant parts.<br />
Paleobotany. This is the study <strong>of</strong> fossiliz<strong>ed</strong> plants. As<br />
parts <strong>of</strong> plants are found, they are given “form genus”<br />
names. For example, a stem section, a leaf, a root, or<br />
a reproductive part such as a se<strong>ed</strong> may all have different<br />
names, even after it is assum<strong>ed</strong> that all belong to<br />
one extinct plant. An illustration <strong>of</strong> an entire fossil plant<br />
is a graphic reconstruction bas<strong>ed</strong> on fossiliz<strong>ed</strong> parts<br />
found.<br />
Of interest...organic evolution: origins and relationships<br />
or past and present life forms are better understood<br />
from their fossil record. By determining the ages<br />
<strong>of</strong> rock formations, it can be determin<strong>ed</strong> when plants<br />
first appear<strong>ed</strong> and when they became extinct or yet<br />
survive.<br />
Economic: Coal deposits result from peat b<strong>ed</strong>s <strong>of</strong> decaying<br />
plants; an example is coal form<strong>ed</strong> during the<br />
Carboniferous (Mississippian and Pennsylvanian). The<br />
term “carboniferous” is <strong>of</strong>ten us<strong>ed</strong> to refer to the two<br />
Paleozoic periods because <strong>of</strong> the extensive coal b<strong>ed</strong>s<br />
form<strong>ed</strong> then. Pressure and heat from overlying rock<br />
s<strong>ed</strong>imentation over millions <strong>of</strong> years compress<strong>ed</strong> and<br />
convert<strong>ed</strong> the peat into coal. One <strong>of</strong> the methods for<br />
finding oil is the study <strong>of</strong> samples, obtain<strong>ed</strong> from drill<br />
holes, <strong>of</strong> micr<strong>of</strong>ossils <strong>of</strong> specific plants, pollen grains,<br />
and animals.<br />
Paleogeography. By studying the distribution <strong>of</strong> certain<br />
fossils over the earth’s crust, it is possible to determine<br />
ancient relationships <strong>of</strong> lands and seas.<br />
Paleoecology. Fossil organisms found together indicate<br />
ancient relationships, environment and climate.
Cordaites<br />
This conifer-like tree, which reach<strong>ed</strong> about<br />
30 meters in height, was prominent during the<br />
Carboniferous. Its trunk (a) was woody; the strapshap<strong>ed</strong>,<br />
or sometimes fan-shap<strong>ed</strong>, leaves (b)<br />
had parallel veins that branch<strong>ed</strong> dichotomously<br />
from the base. The leaves were up to a meter<br />
long. Reproductive structures (c) that resembl<strong>ed</strong><br />
cones on an axis, bore male pollen sacs or<br />
female cone scales with ovules that develop<strong>ed</strong><br />
into wing<strong>ed</strong> se<strong>ed</strong>s after fertilization. (drawing after<br />
Grand ‘Eury, M. F. Cyrille, 1877)<br />
Williamsonia<br />
Cycadoid plants evolv<strong>ed</strong> in the late Carboniferous<br />
and became extinct during the late Cretaceous.<br />
One <strong>of</strong> these, Williamsonia, reach<strong>ed</strong> a height <strong>of</strong><br />
2 meters. The plant had a columnar trunk (d)<br />
mark<strong>ed</strong> with old leaf base scars (e) and whorls<br />
<strong>of</strong> leafy fronds (f) similar to living cycads, although<br />
not relat<strong>ed</strong>. Male pollen sacs and a female se<strong>ed</strong>bearing<br />
organ were borne in a flower-like structure<br />
(g). (drawing after Sahni, 1932, Geologic Survey<br />
<strong>of</strong> India)<br />
COLOR CODE<br />
tan: trunk (a, d)<br />
green: leaves (b, f)<br />
yellow: reproductive structures (c, g)<br />
brown: leaf base scars (e)
Fossils (continu<strong>ed</strong>)<br />
Rhynia<br />
This plant liv<strong>ed</strong> only during the Devonian. Psilotum<br />
(see 64) and Tmesipteris are living plants that resemble<br />
Rhynia but are not known in the fossil record.<br />
Rhynia had simple hair-like rhizoids (a), a creeping underground<br />
stem (rhizome, b) that gave rise to upright,<br />
branching shoots (c) that reach<strong>ed</strong> 50 cm in height. As<br />
there were no leaves, it is assum<strong>ed</strong> photosynthesis took<br />
place in the green stems. Spore cases (sporangia, d)<br />
containing spores were borne at the shoot tips. (drawing<br />
after Hirmer, 1927, R. Oldenbourg)<br />
Lepidodendron<br />
This tree reach<strong>ed</strong> 30 meters in height and was abundant<br />
during the Carboniferous. It is relat<strong>ed</strong> to living lycopods<br />
(see 65). The stem bases (e) and stems (f) were dichotomously<br />
branch<strong>ed</strong> (fork <strong>of</strong> two branches <strong>of</strong> equal<br />
length). Diamond-shape leaf scars cover<strong>ed</strong> the outer<br />
surface <strong>of</strong> the upright stem (g) and upper branch<strong>ed</strong><br />
stems. Extending beyond the leaves (h), cones (i) <strong>of</strong><br />
sporangia with two kinds <strong>of</strong> spores (heterosporous condition)<br />
grew at the tips <strong>of</strong> stems. (drawing after Hirmer,<br />
1927, R. Oldenbourg)<br />
Calamites<br />
A tree that had secondary growth and thick bark,<br />
Calamites reach<strong>ed</strong> 10 meters in height. Although much<br />
smaller and herbaceous, living Equisetum (see 66)<br />
plants greatly resemble this ancient relative that liv<strong>ed</strong><br />
during the Devonian and Mississipian periods. The upright<br />
stem (j) arose from an underground rhizome (k)<br />
and possess<strong>ed</strong> roots (l) at the nodes. Stem nodes<br />
(m) bore whorls <strong>of</strong> stems (n). Stem ends had whorls<br />
<strong>of</strong> ne<strong>ed</strong>le-like leaves (o). (drawing after Hirmer, 1927,<br />
R. Oldenbourg)<br />
43<br />
COLOR CODE<br />
white: rhizoids (a), rhizome (b, k)<br />
green: shoots (c), leaves (h, o), stem (j),<br />
whorls <strong>of</strong> stems (n)<br />
brown: sporangium (d)<br />
tan: stem bases (e), branch<strong>ed</strong> stems (f),<br />
upright stem (g), cones (i)
Blue-greens<br />
Fossil history <strong>of</strong> the blue-greens extends back to the<br />
Precambrian. They are found in water, in and on soil,<br />
on rocks, and in the atmosphere. Habitat temperatures<br />
range from 0 ◦ to 85 ◦ C. Some species occur in lichens,<br />
liverworts, water ferns, cycads, and flowering plants as<br />
symbionts (dissimilar organisms that live together and<br />
may, or may not, be beneficial to each other).<br />
Characteristics. The microscopic blue-greens have<br />
no membrane-bound<strong>ed</strong> nucleus (prokaryotic, pro = before).<br />
[All plants and animals have membrane-bound<br />
cell organelles including nuclei (eukaryotic, eu = true).]<br />
The cell has a mucilaginous sheath <strong>of</strong> pectin that surrounds<br />
the cell wall and an inner cellulose wall.<br />
Cell contents (protoplasm) include nuclear material with<br />
DNA fibrils, chlorophyll a, and accessory pigments<br />
<strong>of</strong> blue (phycocyanins), r<strong>ed</strong> (phycoerythrin), orange<br />
(carotenes), and xanthophylls (yellow) colors. These<br />
pigments are involv<strong>ed</strong> in capture <strong>of</strong> light and subsequent<br />
formation <strong>of</strong> carbohydrates (photosynthesis).<br />
Cyanophycean starch is the storage product.<br />
Blue-green forms may be one cell (unicellular), colonial<br />
(cells held together by a gelatinous sheath), or filamentous<br />
(chains <strong>of</strong> cells call<strong>ed</strong> trichomes). They have no<br />
thread-like structures (flagella) for movement.<br />
Reproduction. Blue-greens have no known sexual reproduction.<br />
Reproduction <strong>of</strong> unicellular forms is by cell<br />
division in which the cell wall folds in and “pinches”<br />
the cell into two cells. Colonial and filamentous forms<br />
fragment into separate pieces. Filamentous forms have<br />
various specializ<strong>ed</strong> cells: an akinete is a resistant cell<br />
fill<strong>ed</strong> with food reserves, which can germinate to form<br />
a new filament; a transparent heterocyst functions in<br />
nitrogen-fixation, and frequently is locat<strong>ed</strong> where the filament<br />
breaks. Some genera have exospores. These<br />
are cells that pinch <strong>of</strong>f the filament.<br />
Of interest...ecosystem: blue-greens are primary colonizers<br />
on bare soil and rock; by forming mats that<br />
bind to the soil surface, they r<strong>ed</strong>uce soil erosion. As<br />
44<br />
nitrogen-fixers, they contribute to soil fertility (e.g.,<br />
growing in rice paddies, Anabaena, in association with<br />
the floating water fern, Azolla, see 70, increases rice<br />
production). Blue-greens contribute to the water plankton<br />
food chain; reef building, in tropical waters bluegreens<br />
precipitate calcium carbonate (limestone) out<br />
<strong>of</strong> water and build up rock layers; toxins: “blooms” <strong>of</strong><br />
dense concentrations in the sea kill marine fish, and in<br />
reservoirs, they may cause gastrointestinal diseases in<br />
cattle and humans.<br />
Synechococcus<br />
Structures <strong>of</strong> this unicellular spherical (coccoid) bluegreen<br />
include a mucilaginous sheath (a), cell wall (b),<br />
plasma membrane (c) and protoplasm (d). Reproduction<br />
is by binary fission (splitting into two).<br />
Cylindrospermum<br />
This filamentous blue-green has an akinete (resistant<br />
cell, e) and a heterocyst (spore-like cell, f) at the end <strong>of</strong><br />
the trichome.<br />
Anabaena<br />
A heterocyst (g) is locat<strong>ed</strong> near the center <strong>of</strong> the trichome.<br />
This filamentous genus is a frequent part <strong>of</strong><br />
water “blooms.” In resevoirs it can cause bad odor and<br />
taste to water, killing birds and animals with endotoxin<br />
(releas<strong>ed</strong> on decomposition).<br />
Gloeotrichia<br />
Colonies <strong>of</strong> trichomes are form<strong>ed</strong>. The taper<strong>ed</strong> trichome<br />
has a heterocyst (h) and an adjacent akinete<br />
(i).<br />
Hapalosiphon<br />
The trichome is branch<strong>ed</strong>, with a heterocyst (j) present.<br />
Branches form as the cells divide on a perpendicular<br />
plane.<br />
COLOR CODE<br />
white: sheath (a), heterocyst (f, g, h, j)<br />
tan: wall (b)<br />
blue-green: protoplasm (d)<br />
dark blue-green: akinete (e, i)
Slime Molds<br />
Even when organisms were group<strong>ed</strong> as either plants or<br />
animals, no one knew what to do with the slime molds.<br />
The creeping acellular phase is animal-like, while the<br />
reproductive structures that produce spores are plantlike.<br />
Now, true slime molds are recogniz<strong>ed</strong> as a separate<br />
taxonomic group.<br />
Characteristics. There are about 450 species <strong>of</strong> slime<br />
molds distribut<strong>ed</strong> worldwide. Most live in shady moist<br />
woods on decaying wood, leaves, or moss. Some occur<br />
in open, but moist areas, such as lawn grass. They can<br />
be found, also, on damp bark mulch us<strong>ed</strong> in gardens.<br />
Their diet is bacteria, protozoa, fungal spores, and other<br />
minute organisms. The body <strong>of</strong> a slime mold is call<strong>ed</strong><br />
a plasmodium (a), consisting <strong>of</strong> a membrane covering<br />
without cell walls, and containing many nuclei. Some<br />
plasmodia move in an amoeba-like fashion, flowing over<br />
surfaces, engulfing nutrients and other food sources.<br />
When temperature or moisture conditions are unfavorable,<br />
the plasmodium may convert to a harden<strong>ed</strong> mass<br />
in a resting dormant condition call<strong>ed</strong> a sclerotium (b).<br />
Or with a temporarily dry environment, the plasmodium<br />
may mature to the fruiting stage.<br />
In the spring in north temperate regions slime molds can<br />
be found on wet rotting logs and examin<strong>ed</strong> with a hand<br />
lens. Throughout the summer, various forms <strong>of</strong> fruiting<br />
bodies can be discover<strong>ed</strong>, such as those shown here.<br />
Reproduction. The life cycle consists <strong>of</strong> the plasmodium<br />
fusing with other plasmodia, increasing the number<br />
<strong>of</strong> nuclei, which divide simultaneously; engulfing<br />
food; and eventually, converting into fruiting bodies<br />
call<strong>ed</strong> fructifications. The three types <strong>of</strong> fructifications<br />
form<strong>ed</strong> by various species are sporangia, aethalia, and<br />
plasmodiocarps.<br />
45<br />
A sporangium may have a stalk (h) or not, with a base<br />
call<strong>ed</strong> a hypothallus (i), and a wall <strong>of</strong> varying lime content,<br />
the peridium (g), that encloses the spores. Inside<br />
the peridium may be a non-living network <strong>of</strong> hairs, capillitium<br />
(f), that aid in spore dispersal.<br />
An aethalium is cushion-shap<strong>ed</strong> with a peridium (o)<br />
enclosing the spores, such as Lycogala shown here.<br />
The third type <strong>of</strong> fructification is a plasmodiocarp,<br />
which retains the net-shape <strong>of</strong> the plasmodium.<br />
By r<strong>ed</strong>uction division (meiosis), 1n spores are produc<strong>ed</strong>.<br />
With favorable environmental conditions, the<br />
spore germinates into a myxamoeba without flagella<br />
(flagella, pl.; flagellum, sing. = whip-like structure for<br />
movement) or a swarm cell with flagella. These cells<br />
function as sex cells (gametes). Two cells fuse to form a<br />
2n zygote nucleus, which divides mitotically to develop<br />
into a plasmodium.<br />
Of interest...blue lawn infestation: Physarum<br />
cinereum; research material: slime molds provide<br />
pure, cell-less protoplasm for genetic, developmental,<br />
and cancer studies; ecosystem: primary decomposers<br />
in the forest food chain.<br />
COLOR CODE<br />
yellow: plasmodium (a), sclerotia (b)<br />
yellow-brown: dri<strong>ed</strong> plasmodium (c), capillitium (f)<br />
gray: stalk(d), peridium (e)<br />
tan: peridium (g), wood (y)<br />
dark brown: stalk (h), hypothallus (i)<br />
brown: spores (j)<br />
black: stalk (k)<br />
white: lime dots on peridium (l),<br />
hypothallus (v), stalk (w)<br />
dark brown: peridium (z, p), stalk (m, q)<br />
green: moss (n)<br />
pink: peridium (o)<br />
orange-brown: hypothallus (r), stalk (s),<br />
peridium(t),capillitium(u)<br />
iridescent (dots<br />
<strong>of</strong> green,<br />
r<strong>ed</strong>, yellow): peridium (x)<br />
orange: plasmodiocarp
Water Molds, Downy Mildews,<br />
White Rusts<br />
In this Oomycete group, organisms are microscopic<br />
and found in water and moist soil. The most advanc<strong>ed</strong><br />
forms live entirely within a plant or animal host. They<br />
range from one cell to copious amounts <strong>of</strong> threadlike<br />
strands. Each strand <strong>of</strong> a threadlike tubular filament<br />
is call<strong>ed</strong> a hypha (pl. hyphae). A mass <strong>of</strong><br />
hyphae is call<strong>ed</strong> mycelium. The cell wall contains<br />
cellulose.<br />
Reproduction is by oospores, sexually produc<strong>ed</strong>, nonmotile<br />
cells; and, asexually, by zoospores with two unlike<br />
flagella that are us<strong>ed</strong> for motility.<br />
Of interest...Albugo spp. (causes white rust <strong>of</strong> horseradish,<br />
cabbage, sweet potato, morning glory, spinach),<br />
Aphanomyces (causes root disease <strong>of</strong> sugar beets,<br />
peas), Phytophthora infestans (causes late blight <strong>of</strong><br />
potato), Phytophthora ramorum (causes sudden oak<br />
death), Plasmopara viticola (causes downy mildew <strong>of</strong><br />
grapes). Pythium debaryanum (causes damping-<strong>of</strong>f <strong>of</strong><br />
se<strong>ed</strong>lings), Saprolegnia (causes disease <strong>of</strong> fish eggs<br />
and fish).<br />
Achyla<br />
The water mold illustrat<strong>ed</strong> here has separate male<br />
and female individuals. Eggs (a) are produc<strong>ed</strong> in an<br />
egg chamber (oogonium, b) on the hypha (c). From<br />
a male individual, antheridia (d) with male gametes<br />
branch from a hypha (e). After fertilization by a male<br />
gamete from the antheridium, an egg develops into a<br />
2n oospore (f). The oospore germinates to form a new<br />
body <strong>of</strong> hyphal stands (g) that produces biflagellat<strong>ed</strong><br />
zoospores (h).<br />
46<br />
Chytrids and Allies<br />
The Chytridiomycetes are simple, microscopic organisms<br />
that live in both water and soil. They may be a<br />
single cell living within the cell <strong>of</strong> a host alga or higher<br />
plant or have true mycelia and live on the surface <strong>of</strong> a<br />
host. The motile cells have one whiplash flagellum. The<br />
cell walls <strong>of</strong> chytrids are made up <strong>of</strong> chitin, a tough resistant<br />
carbohydrate. Some have cellulose in their cell<br />
walls also.<br />
Of interest...Some chytrid parasites destroy algae.<br />
Some are parasitic on economic plants that include<br />
Physoderma (causes brown spot <strong>of</strong> corn), Synchytrium<br />
(causes black wart disease <strong>of</strong> potato tubers), and<br />
Urophlyctis (causes crown wart <strong>of</strong> alfalfa).<br />
Allomyces<br />
The 2n mycelium <strong>of</strong> this chytrid produces thin-wall<strong>ed</strong><br />
spore-bearing structures call<strong>ed</strong> sporangia on hyphal<br />
strands (i). From a sporangium (j), 2n spores (k)<br />
emerge. Other, thick-wall<strong>ed</strong> sporangia (l) produce 1n<br />
spores (m) by meiosis (nuclear divisions that r<strong>ed</strong>uce<br />
the number <strong>of</strong> chromosomes by half). A 1n spore germinates<br />
into a 1n hypha (n), which produces 1n sex<br />
cells (gametes, o, p) in gametangia (q). Fusion <strong>of</strong> unlike<br />
gametes into a zygote (r) results in the germination<br />
<strong>of</strong> spore-bearing hyphae (i).<br />
COLOR CODE<br />
optional: egg (a) gamete (o, p), antheridia (d),<br />
oospore (f), zygote (r)<br />
gray: oogonium (b), hypha (c, e, g, i, n)<br />
yellow: zoospores (h, k, m)<br />
colorless: sporangium (j, l), gametangia(q)
Fungi<br />
Characteristics: Fungi are organisms without<br />
chlorophyll, and therefore, are dependent on other<br />
organisms for nutrition. A saprophytic fungus obtains<br />
food from dead organic matter. A parasitic fungus<br />
fe<strong>ed</strong>s upon a living organism, the host. Symbiotic<br />
fungi live in a mutually beneficial relationship with a<br />
host. A fungus associat<strong>ed</strong> with roots <strong>of</strong> a higher plant,<br />
call<strong>ed</strong> a mycorrhizal association, may be parasitic or<br />
symbiotic. In a symbiotic relationship both the plant and<br />
the fungus benefit. The fungal associate on plant roots<br />
produces digestive enzymes (proteases/peptidases)<br />
that release amino acids from proteins and absorb<br />
extra amounts <strong>of</strong> phosphorus from the soil, thence to<br />
the plant. The fungus benefits by using carbon—basal<br />
metabolites (e.g., sugars, amino acids, vitamins) from<br />
the plant roots.<br />
Carl Zimmer report<strong>ed</strong> in 1997 that Suzanne Simard,<br />
a forest ecologist, discover<strong>ed</strong> a fungal mycelium connect<strong>ed</strong><br />
to several trees and even trees <strong>of</strong> different<br />
species. A forest community <strong>of</strong> plants can be ecologically<br />
interconnect<strong>ed</strong> to the point where removal <strong>of</strong> socall<strong>ed</strong><br />
we<strong>ed</strong> trees disrupts the survival <strong>of</strong> the entire<br />
group <strong>of</strong> plants. She conclud<strong>ed</strong> that the fungus extract<strong>ed</strong><br />
carbon from healthy trees and shar<strong>ed</strong> it with<br />
trees growing under unfavorable light conditions. It is<br />
thus important to maintain diversity in forests for the<br />
health <strong>of</strong> all the plants.<br />
Fungi range in size from one-cell<strong>ed</strong>, microscopic organisms<br />
to masses <strong>of</strong> cells strung together in long filamentous<br />
strands. Each strand is call<strong>ed</strong> a hypha. The<br />
mass <strong>of</strong> hyphae that make up a fungal body is call<strong>ed</strong><br />
mycelium. Cell walls are made up <strong>of</strong> chitin, which is<br />
hard and resists water loss.<br />
Reproduction. All fungi bear spores that germinate<br />
into strands <strong>of</strong> hyphae. The microscopic lower fungi<br />
mainly live within a host and reproduce mostly by asexual<br />
spores. Higher fungi have elaborate fruiting bodies,<br />
compos<strong>ed</strong> <strong>of</strong> hyphae, in which spores are produc<strong>ed</strong>.<br />
Sexual reproduction, us<strong>ed</strong> as the basis <strong>of</strong> fungal classification,<br />
commonly occurs once a year.<br />
Black Bread Mold and Allies<br />
Their sexual resting spores (zygospores) define zygomycete<br />
fungi. Another characteristic is the asexual,<br />
non-motile, reproductive spore. Of interest...Rhizopus<br />
stolonifer (causes black bread mold, strawberry leak,<br />
47<br />
and sweet rot <strong>of</strong> potatoes), Choanephora cucurbitarium<br />
(causes squash flower and fruit mold); Absidia sp.,<br />
Mucor spp., Rhizopus sp. (can be fatal to the human<br />
nervous system).<br />
Mucor<br />
Hyphae (a) <strong>of</strong> compatible mating types develop side<br />
branches (b) that meet. A swelling or progametangium<br />
(c) is produc<strong>ed</strong> at each side. The walls (d) between the<br />
two break down. The nuclei from each progametangium<br />
fuse together and form a zygospore (e) that is held by<br />
suspensors (f).<br />
Sac Fungi<br />
Ascomycete fungi sexually produce usually 4 or 8 ascospores<br />
(g) within a sac sporangium call<strong>ed</strong> an ascus<br />
(h). Asexual reproduction occurs by breaking <strong>of</strong>f<br />
(fragmentation) <strong>of</strong> mycelium, by splitting <strong>of</strong> one cell into<br />
two cells (fission), by budding <strong>of</strong> cells, and by formation<br />
<strong>of</strong> conidia. Fungi in the Hemiascomycetidae have<br />
little or no mycelia and the asci are not produc<strong>ed</strong> in<br />
a spore-bearing structure or fruiting body. Yeasts have<br />
evolv<strong>ed</strong> from several evolutionary lines, but are group<strong>ed</strong><br />
together for convenience. They are found in sugary substances<br />
such as flower nectar and on the surface <strong>of</strong><br />
fruits, in soil, in animal wastes, in milk, and in other substances.<br />
They have the ability to ferment carbohydrates,<br />
producing alcohol and carbon dioxide, as in wine and<br />
beer making. The leaf curl disease-causing fungi are<br />
classifi<strong>ed</strong> with the yeasts, as both may form buds on the<br />
ascospores. Of interest...Saccharomyces cerevisiae<br />
(baker’s and brewer’s yeast), Taphrina spp. (causes leaf<br />
curl or peach, chokecherry, oak, witch’s broom <strong>of</strong> cherries).<br />
Saccharomyces cerevisiae Yeast<br />
Yeasts are microscopic, unicellular organisms (i). Asexual<br />
reproduction occurs by cell division and budding (j).<br />
Sexual reproduction, while rare, is by fusion <strong>of</strong> two cells<br />
to form an ascus (k) with 4 ascospores (l).<br />
Taphrina deformans Peach Leaf Curl<br />
Budding spores infect the peach leaf (m) producing<br />
more buds or mycelia, which penetrate the leaf tissue.<br />
The host tissue reacts to this infection by forming<br />
swollen, tumor-like masses (n) and by tortuous curling<br />
<strong>of</strong> the leaves.
COLOR CODE<br />
gray: hypha (a), tips (b), progametangium<br />
(c), zygospore (e), suspensors (f)<br />
yellow: ascospore (g, l)<br />
beige: cell (i, j)<br />
colorless: ascus (h, k)<br />
brown: masses (n)<br />
green: leaf (m)
Molds, Mildews, Morels (Sac Fungi)<br />
Usually members <strong>of</strong> this Euascomycetidae group have<br />
asci (sac sporangia) enclos<strong>ed</strong> in a fruiting body call<strong>ed</strong><br />
an ascocarp. A cleistothecium, a perithecium, and<br />
an apothecium are types <strong>of</strong> ascocarps. A cleistothecium<br />
(c) is an enclos<strong>ed</strong> ascocarp compos<strong>ed</strong> <strong>of</strong> loose<br />
masses <strong>of</strong> hyphae with asci irregularly arrang<strong>ed</strong> within.<br />
A perithecium (h) is a vase-shap<strong>ed</strong> ascocarp with a<br />
pore (ostiole, i) at the top. It may be emb<strong>ed</strong>d<strong>ed</strong> in a compact<strong>ed</strong><br />
mycelial structure (stroma, j). An apothecium<br />
is a cup-shap<strong>ed</strong> ascocarp with asci lining the open surface<br />
(see 54, Xanthora, j).<br />
Of interest...molds: Aspergillus spp. (mold on<br />
bread, leather; causes human skin and respiratory<br />
disease), Aspergillus oryzae is us<strong>ed</strong> to make sake<br />
from rice in Japan, Claviceps purpurea (ergot <strong>of</strong> rye),<br />
Neurospora (pink bread mold), Penicillium italicum<br />
(blue mold on citrus fruits and preserves), P. digitatum<br />
(green mold on citrus fruits), P. camemberti (flavoring<br />
in Camembert cheese), P. roqueforti (for flavor in<br />
production <strong>of</strong> Roquefort cheese), P. notatum and P.<br />
chrysogenum (source <strong>of</strong> the antibiotic, penicillin);<br />
Rhizopus nigricans (black bread mold); wilts: Ceratocystis<br />
spp. (oak wilt, Dutch elm disease); blight:<br />
Endothia parasitica (chestnut blight); powdery<br />
mildews: Chaetomium (<strong>of</strong> clothes), Podosphaera<br />
leucotricha (<strong>of</strong> apple), Sphaerotheca pannosa<br />
(<strong>of</strong> roses); rot: Monilinia fructicola (brown rot <strong>of</strong><br />
stone fruits such as peach, plum, cherry, apricot);<br />
wild: Helvella and Gyromitra (false morels),<br />
Morchella (morel), Tuber maganatum (white truffle),<br />
T. melanosporum (black Perigord truffle), Verpa (bell<br />
morel).<br />
Truffles form a mycorrhizal association with roots <strong>of</strong><br />
oak, hazel, poplar and many other trees. Of the 200<br />
species, two <strong>ed</strong>ible species are found in France and<br />
Italy. Hunters using train<strong>ed</strong> pigs and dogs gather them.<br />
Small mammals (chipmunks, voles and squirrels) fe<strong>ed</strong><br />
on truffles and disperse fungal spores in their fecal<br />
matter.<br />
Penicillium<br />
Asexual reproduction occurs by microscopic spores<br />
call<strong>ed</strong> conidia (a) form<strong>ed</strong> on the side <strong>of</strong> a hyphal strand<br />
(b). By subjecting conidia <strong>of</strong> Penicillium chrysogenum<br />
to ultra-violet irradiation, surviving colonies have a high<br />
yield for penicillin production. It is a naturally occurring<br />
antibiotic. Discovery came when it was observ<strong>ed</strong> that<br />
48<br />
in Petri dishes, bacterial colonies di<strong>ed</strong> when “contaminat<strong>ed</strong>”<br />
with Penicillium.<br />
Microsphaera alni Powdery Mildew <strong>of</strong> Lilac<br />
The microscopic fruiting body is a cleistothecium. The<br />
wall (c) has been broken to reveal 2 asci (d) with ascospores<br />
(e). Appendages (f) aid in spore dispersal.<br />
Diatrypella<br />
In this fruiting body, asci (g) line perithecia (h) with terminal<br />
pores (i). They are emb<strong>ed</strong>d<strong>ed</strong> in a hyphal stroma<br />
(j).<br />
Morchella Morel<br />
Easily recogniz<strong>ed</strong>, this <strong>ed</strong>ible mushroom is priz<strong>ed</strong> for its<br />
distinctive flavor. Apothecia with asci line the cavities (k)<br />
<strong>of</strong> the spongy-looking fruiting body. In spring, morels are<br />
a mushroom hunter’s favorite find in northern deciduous<br />
wood<strong>ed</strong> areas.<br />
Claviceps purpurea Ergot <strong>of</strong> Rye<br />
An ascospore germinates to form a mat <strong>of</strong> mycelium<br />
on a rye flower (see 123). Instead <strong>of</strong> a rye grain (m)<br />
developing, the fungal mycelium forms an overwintering<br />
asexual mass—a dark, harden<strong>ed</strong> sclerotium (n).<br />
This sclerotium contains ergot alkaloids that poison cattle<br />
when grazing and humans when eating contaminat<strong>ed</strong><br />
rye flour products. Also in humans, ergot causes<br />
gangrene.<br />
Xylaria Dead Man’ Finger<br />
Perithecia are emb<strong>ed</strong>d<strong>ed</strong> in the outer wall <strong>of</strong> the stroma<br />
(o) or “finger,” which develops on rotten, burn<strong>ed</strong> wood.<br />
Mycelial filaments (p) are shown.<br />
Daldinia concentrica<br />
A vertical section reveals perithecia (q) lining the outer<br />
stromatic surface (r) <strong>of</strong> this cushion-shap<strong>ed</strong> fruiting<br />
body.<br />
Geoglossum difforme, Microglossum rufum<br />
Earth Tongues<br />
Apothecia <strong>of</strong> asci form on the surface <strong>of</strong> the club-shap<strong>ed</strong><br />
fruiting bodies (s, t).
COLOR CODE<br />
yellow: conidia (a), ascospore (e), ascus (g)<br />
colorless: ascus (d), pores (i), filaments (p),<br />
perithecium (q)<br />
gray: hypha (b), perithecium (h), stroma (o)<br />
black: wall (c), stroma (j), fruiting body (s)<br />
white: appendages (f)<br />
beige: fruiting body (k, l)<br />
gold: grain (m)<br />
dark brown: sclerotium (n), stalk (u)<br />
purple: stroma (r)<br />
orange-r<strong>ed</strong>: fruiting body t)<br />
green: moss (v)
Rusts, Smuts, Jelly Fungi<br />
(Club Fungi)<br />
For club fungi sexual reproduction results in usually 4<br />
basidiospores (a) produc<strong>ed</strong> on the outside <strong>of</strong> a microscopic<br />
club-shap<strong>ed</strong> sporangium call<strong>ed</strong> a basidium (b).<br />
When basidia are borne in a fruiting body, it is call<strong>ed</strong><br />
a basidiocarp. Familiar forms are mushrooms, shelf<br />
fungi and puffballs. Also includ<strong>ed</strong> are rusts, smuts, jellies,<br />
stickhorns, bird’s-nest fungi, coral fungi and earth<br />
stars. There are many <strong>ed</strong>ible species; however, there<br />
are no rules, only myths, for distinguishing poisonous<br />
from <strong>ed</strong>ible fungi. There are about 22,000 species <strong>of</strong><br />
basidiomycetes.<br />
Rusts (Ur<strong>ed</strong>inales). Fungi in this order are obligate<br />
parasites (require living hosts) on plants. No fruiting<br />
bodies are produc<strong>ed</strong>. Classification is bas<strong>ed</strong> on<br />
the presence <strong>of</strong> teleutospores, representing the overwintering,<br />
resting stage. Many rusts attack only specific<br />
plants. Some require two hosts to complete their<br />
life cycles. For example, wheat rust alternates between<br />
wheat (Triticum) and barberry (Berberis)—unrelat<strong>ed</strong><br />
hosts. This is call<strong>ed</strong> heteroecism (different homes).<br />
Of interest...Cronarium ribicola (white pine blister<br />
rust with currants and gooseberries as the alternate<br />
hosts), Gymnosporangium spp. (rusts <strong>of</strong> juniper, apple,<br />
hawthorn, and pear), Piccinia spp. (rusts <strong>of</strong> wheat, barley,<br />
oats, rye, and hollyhock), Ur<strong>ed</strong>inopsis osmundae<br />
on alternate hosts <strong>of</strong> balsam fir (Abies balsamea) and<br />
cinnamon fern (Osmunda cinnamomea).<br />
Gymnosporangium juniperi-virginianae<br />
The life cycle <strong>of</strong> this fungus is complet<strong>ed</strong> by alternation<br />
<strong>of</strong> the fungus between apple (Malus) and r<strong>ed</strong> c<strong>ed</strong>ar (Juniperus<br />
virginiana) host plants. The c<strong>ed</strong>ar apple gall (c)<br />
is a mass <strong>of</strong> mycelium on c<strong>ed</strong>ars (d). During spring,<br />
gelatinous structures, telia (e), expand with water uptake<br />
(e.g., from rainfall) and protrude from the surface.<br />
Inside a telium are hundr<strong>ed</strong>s <strong>of</strong> teleutospores, basidial<br />
structures that produce basidiospores after germination<br />
on apple trees.<br />
Smuts (Ustilaginales). Smuts form masses <strong>of</strong> black,<br />
sooty-looking teleutospores. Smuts are similar to rusts<br />
but do not ne<strong>ed</strong> living host material and can be grown in<br />
the laboratory. Of interest...Tilletia foetia (bunt or stinking<br />
smut <strong>of</strong> wheat), Ustilago spp. (smut <strong>of</strong> corn, oats),<br />
Urocystis cepulae (onion smut). Ustilago maydis (corn<br />
49<br />
smut) is sold as a gourmet food call<strong>ed</strong> “corn mushroom.”<br />
Economically, smuts cause extensive damage to crops<br />
and consequent r<strong>ed</strong>uctions in yields.<br />
Urocystis cepulae Onion Smut<br />
Black teleutospores (f) form an infestation on bulbs <strong>of</strong><br />
onions (g). This is commonly seen on commercially sold<br />
onions.<br />
Jelly Fungi (Auriculariales). Fruiting bodies <strong>of</strong> gelatinous<br />
material are produc<strong>ed</strong>. When wet, basidia are<br />
form<strong>ed</strong>. Most genera are saprobic, living on dead organic<br />
matter. A few genera are parasitic on mosses<br />
and flowering plants. Of interest...Herpobasidium deformans<br />
(blight <strong>of</strong> honeysuckle).<br />
Auricularia auricula Ear Fungus<br />
The gelatinous fruiting body (h) resembles a human ear.<br />
Jelly Fungi (Tremellales). Fruiting bodies are gelatinous<br />
with leaf-like folds that vary in color with species<br />
from white, pink, yellow, and orange to r<strong>ed</strong>.<br />
Tremella mesenterica<br />
This jelly fungus (i) is found on hardwood tree bark (j).<br />
Some species are <strong>ed</strong>ible.<br />
Jelly Fungi (Dacrymycetales). Waxy, bright-color<strong>ed</strong><br />
gelatinous fruiting bodies are produc<strong>ed</strong>. The yellow coloring<br />
is due to β-carotene pigment. They grow on living<br />
or dead trees.<br />
Dacryopinax spathularia<br />
This jelly fungus (k) is found on rotting wood (l).<br />
COLOR CODE<br />
yellow: basidiospore (a), onion (g)<br />
tan: basidium (b), fruiting body (h)<br />
orange: telium (e), fruiting body (k)<br />
brown: gall (c), wood (l)<br />
green: c<strong>ed</strong>ar (d)<br />
pale yellow: fruiting body (i)<br />
gray: bark (j)
Gill Fungi<br />
Gill, Pore, Coral, and Tooth<strong>ed</strong> Fungi (Agaricales).<br />
In this order, a basidium usually produces 4 basidiospores,<br />
which are forcibly discharg<strong>ed</strong> from the fruiting<br />
body. Fruiting bodies may occur in forms commonly<br />
known as mushrooms, toadstools, shelves, corals, and<br />
tooth<strong>ed</strong> fungi.<br />
A “spore print” (basidiospore collection) can be made<br />
by placing a fruiting body cap with gills or pores half on<br />
white paper, half on black paper. If dark spores are discover<strong>ed</strong>,<br />
use an entire cap on white paper and if light<br />
spores use black paper. Spore color is useful for identification.<br />
If can be white, pink, yellow, brown, purple, or<br />
black.<br />
Of interest...food: Agaricus campestris (commercial<br />
mushroom), Calvatia gigantea (giant puffball),<br />
Cantharellus cibarius (chanterelle), Lentinus <strong>ed</strong>odes<br />
(shiitake, high in vitamin B12, cobalamin; grown commercially<br />
on white oak logs to produce fruiting bodies<br />
for up to 10 years after inoculating the mycelium<br />
in holes drill<strong>ed</strong> in the logs. Logs are stack<strong>ed</strong> crisscross<strong>ed</strong><br />
like Lincoln logs in the shade <strong>of</strong> deciduous<br />
forests and water<strong>ed</strong> frequently with sprinklers. This<br />
technique is widely us<strong>ed</strong> in Korea and now in the U.S.<br />
by Korean entrepreneurs.), Pleurotus ostreatus (oyster<br />
mushroom, this mushroom is grown commercially<br />
on vertically stack<strong>ed</strong> sections <strong>of</strong> American elm, Ulmus<br />
americana, trunks cover<strong>ed</strong> with black plastic film.);<br />
wild: Amanita verna (destroying angel, contains a<br />
deadly poison that destroys liver and kidney cells),<br />
Armillaria mellea (honey mushroom, causes root rot <strong>of</strong><br />
trees, exhibits bioluminescence or “fox-fire” in myceliapenetrat<strong>ed</strong><br />
organic matter), Boletus <strong>ed</strong>ulis (porous<br />
mushroom), Ganoderma applanatum (shelf or bracket<br />
fungus, a type <strong>of</strong> artist’s fungus, so call<strong>ed</strong> because<br />
marks made on the smooth white underside will remain<br />
when the mushroom dries), Marasmius oreades<br />
50<br />
(fairy ring mushroom), Polyporus sulphureus (sulfur<br />
mushroom, causes wood rot <strong>of</strong> trees), P. squamosus<br />
(heart rot <strong>of</strong> trees), Psilocybe spp. (hallucinogenic<br />
mushrooms). Psilocybe mushrooms in Mexico are collect<strong>ed</strong>,<br />
dri<strong>ed</strong>, and serv<strong>ed</strong> in pairs by women in all-night<br />
religious ceremonies <strong>of</strong> Amerinds, as document<strong>ed</strong> by<br />
the famous Harvard University botanist, Charles Evans<br />
Schultes.<br />
Amanita muscaria Fly Amanita, Fly Agaric<br />
The fruiting body <strong>of</strong> a gill mushroom begins as a mass <strong>of</strong><br />
hyphal cells and enlarges into a “button.” At this stage,<br />
the fruiting body is surround<strong>ed</strong> by a universal veil (d).<br />
As expansion <strong>of</strong> the gills (lamellae) takes place, the veil<br />
is broken. The veil may remain as patches or scales (b)<br />
on the cap (pileus) and as veil remnants (c) or as a cup<br />
(volva) at the base <strong>of</strong> the stalk (stipe).<br />
Some species <strong>of</strong> agarics also have an inner or partial<br />
veil (d) between the developing stalk (e) and gills (f).<br />
When the partial veil is broken upon expansion <strong>of</strong> the<br />
gills, it may remain attach<strong>ed</strong> to the stalk as a ring (annulus,<br />
g) or remain attach<strong>ed</strong> to the margin <strong>of</strong> the cap,<br />
hanging down as a curtain, as in Cortinarius.<br />
The microscopic basidia are borne on the inner surface<br />
<strong>of</strong> the gill. Individual cap (h) color in this species<br />
varies from white, yellow, and orange to r<strong>ed</strong>. This is<br />
a poisonous mushroom, found mostly in mycorrhizal<br />
association (see 12) with roots <strong>of</strong> aspen and conifer<br />
trees.<br />
Cortinarius<br />
Remains <strong>of</strong> the partial veil, which hangs down from the<br />
cap as a curtain (cortina), form web-like lines (i) on the<br />
stalk (j). As the cap expands, gills (k) are expos<strong>ed</strong>. This<br />
fruiting body was found in a beech-maple forest.<br />
COLOR CODE<br />
white: scales (b), veil remnants (c), partial<br />
veil (d), stalk (e), gills (f), annulus (g)<br />
orange-r<strong>ed</strong>: cap (h)<br />
light tan: stalk (j), gills (k)<br />
yellow: cap margin (l)<br />
yellow-brown: cap center (m)
Gill and Pore Fungi<br />
Agaricales (continu<strong>ed</strong>)<br />
Coprinus comatus Shaggy Mane<br />
As the white fruiting body matures, the gills undergo<br />
self-digestion with black basidiospores releas<strong>ed</strong> in an<br />
inky black fluid. This mushroom is found in lawns, golf<br />
courses and fields and is <strong>ed</strong>ible and preferr<strong>ed</strong> in the<br />
button stage before dripping black fluid. Remnant <strong>of</strong> a<br />
veil (a) remains on top. Caution: when eating this mushroom,<br />
alcoholic drinks should not be taken; otherwise,<br />
you can become quite ill!<br />
Chantharellus cinnabarinus Cinnabar<br />
Chanterelle<br />
Basidiospores are produc<strong>ed</strong> on blunt gills (b). With age,<br />
the cap (c) becomes funnel-shap<strong>ed</strong> on the fruiting body<br />
stalk (d). This mushroom is <strong>ed</strong>ible and found in forests<br />
throughout the Unit<strong>ed</strong> States and Canada. It is consider<strong>ed</strong><br />
a gourmet treat, sold in grocery markets and us<strong>ed</strong><br />
in restaurant <strong>of</strong>ferings.<br />
Russula emetica Emetic Russula<br />
The fruiting body has a stout stalk (e) supporting a bright<br />
r<strong>ed</strong> cap (f) with white, brittle gills (g). This fragile fruiting<br />
body is probably poisonous.<br />
Suillus americanus<br />
Instead <strong>of</strong> gills, this mushroom has fleshy pores (h) and<br />
is therefore designat<strong>ed</strong> as a bolete. Basidia line the<br />
inner surfaces <strong>of</strong> layers <strong>of</strong> tubes with pore openings.<br />
The fruiting body is fleshy and decays quickly. Brown<br />
scales (i) dot the yellow cap (j). It is <strong>ed</strong>ible, but little<br />
flesh remains after the tubes have been remov<strong>ed</strong>.<br />
51<br />
COLOR CODE<br />
light tan: veil remnant (a)<br />
dark orange: gills (b), cap (c), stalk (d)<br />
pale pink: stalk (e)<br />
r<strong>ed</strong>: cap (f)<br />
white: gills (g)<br />
yellow: pores (h), cap (j), stalk (k)<br />
brown: scales (i)<br />
green: moss (l)
Pore, Coral, and Tooth<strong>ed</strong> Fungi<br />
Agaricales (continu<strong>ed</strong>)<br />
Coriolus (Polyporus, Trametes) versicolor<br />
Turkey-tail Fungus<br />
In polypore ( = many pores) fungi, basidia are form<strong>ed</strong> on<br />
the inner surface <strong>of</strong> leathery pores (a) on the lower portion<br />
<strong>of</strong> the fruiting body (b). This fan-shap<strong>ed</strong> bracket fungus<br />
is found on rotting wood. The bands <strong>of</strong> tan, brown,<br />
white are like the colors <strong>of</strong> a turkey’s tail feathers, and<br />
thus account for the common name.<br />
Fomes formentarius Rusty-ho<strong>of</strong> Fungus<br />
This perennial polypore adds new growth (c) yearly to<br />
the woody bracket-type fruiting body (d). It is parasitic<br />
on birch (Betula) and beech (Fagus, e) and some other<br />
hardwood deciduous trees. It is shap<strong>ed</strong> like a horse’s<br />
ho<strong>of</strong> and is common in northern temperate zones.<br />
Irpex lacteus Crust Polypore<br />
A crust-like fruiting body (f) <strong>of</strong> this polypore grows on<br />
the lower surface <strong>of</strong> dead tree limbs (g).<br />
Clavulinopsis fusiformis Coral Fungus<br />
The fruiting body (h) in this coral fungus is simple and<br />
unbranch<strong>ed</strong>.<br />
Ramaria stricta Straight Coral Fungus<br />
This coral fungus has a more complexly branch<strong>ed</strong> fruiting<br />
body (i). It is usually found on rotting beech (Fagus)<br />
wood.<br />
Hericium Tooth<strong>ed</strong> Fungus<br />
Basidia are produc<strong>ed</strong> on downward-point<strong>ed</strong>, tooth-like<br />
projections on the fruiting body (j). It is found on dead<br />
deciduous hardwood trees.<br />
52<br />
COLOR CODE<br />
tan-brown-white bands: fruiting body (a, b)<br />
rust (yellow-brown-r<strong>ed</strong>): new growth (c)<br />
dark and light gray bands: fruiting body (d)<br />
brown: bark (e)<br />
yellow-tan: fruiting body (f, i)<br />
gray: bark (g)<br />
orange: fruiting body (h)<br />
white: fruiting body (j)
Puffballs, Stinkhorns,<br />
Bird’s-nest Fungi<br />
Puffball Fungi (Lycoperdales). Spores are dispers<strong>ed</strong><br />
by wind from puffball fruiting bodies. An inner fertile portion,<br />
call<strong>ed</strong> the gleba, is compos<strong>ed</strong> <strong>of</strong> basidiospores<br />
and sterile thread-like structures (capillitia). Powdery<br />
masses <strong>of</strong> spores are expos<strong>ed</strong> when the puffball wall<br />
(peridium) disintegrates, or emerge in a cloud from<br />
an opening (ostiole) when the flexible peridium is disturb<strong>ed</strong>.<br />
Of interest . . . Calvatia gigantea (giant puffball) found<br />
in mostly open or sometimes wood<strong>ed</strong> areas and after<br />
rains in late summer or early autumn and is <strong>ed</strong>ible when<br />
pure white inside, Geastrum and Astraeus (earthstars),<br />
Lycoperdon (stalk<strong>ed</strong> puffball).<br />
Geastrum Earthstar<br />
This type <strong>of</strong> puffball has a star shape when the rigid<br />
outer wall or peridium (a) becomes wet and splits<br />
open. An inner flexible peridium (b) is expos<strong>ed</strong>. A single<br />
pore (ostiole, c) for spore dispersal occurs at the<br />
center.<br />
Lycoperdon Stalk<strong>ed</strong> Puffball<br />
At maturity, a powdery gleba <strong>of</strong> spores (d) puffs out <strong>of</strong><br />
an ostiole (e) in the peridium (f) due to rain drops or<br />
other physical disturbances.<br />
Stinkhorn Fungi (Phallales). Basidiospores are<br />
form<strong>ed</strong> within a gleba. A receptacle, bearing the gleba,<br />
emerges from a protective enclosure, the peridium. As<br />
the gleba breaks down, the basidiospores are expos<strong>ed</strong><br />
in a gelatinous mass at the top <strong>of</strong> the stinkhorn. The<br />
foul smell <strong>of</strong> the mass attracts flies, which disperse the<br />
spores.<br />
Of interest...Dictyophora (collar<strong>ed</strong> stinkhorn), Clathrus<br />
(net stinkhorn), Mutinus (dog stinkhorn), Phallus<br />
(common stinkhorn)<br />
53<br />
Dictyophora duplicata Collar<strong>ed</strong> Stinkhorn<br />
At the egg stage, the peridium (g) encloses the gleba<br />
(h) where basidia and basiospores are form<strong>ed</strong>. The receptacle<br />
(i) and stalk (k) will enlarge and emerge from<br />
the peridium, which remains at the base.<br />
Mutinus caninus Dog Stinkhorn<br />
From the broken peridium (k), a pink stalk (l) emerges.<br />
The dark pink receptacle (m) at the top <strong>of</strong> the fruiting<br />
body is cover<strong>ed</strong> by a green, slimy mass (gleba, n) <strong>of</strong><br />
spores.<br />
Bird’s-nest Fungi (Nidulariales). The fruiting body<br />
appears as a hollow nest fill<strong>ed</strong> with egg-like peridioles,<br />
which contain basidiospores. The nest acts as a<br />
splashcup. Raindrops cause the periodioles to bounce<br />
out <strong>of</strong> the fruiting body. The periodiole’s sticky covering<br />
adheres to nearby surfaces where the spores are then<br />
releas<strong>ed</strong>. This type <strong>of</strong> fungus is <strong>of</strong>ten found on rotting<br />
bark mulch us<strong>ed</strong> in gardening and on deciduous forest<br />
duff litter.<br />
Of interest . . . Nidularia (white bird’s-nest fungus), Crucibulum<br />
(common bird’s nest fungus), Cyathus (striate<br />
bird’s-nest fungus).<br />
Crucibulum vulgare Common Bird’s-nest<br />
Fungus<br />
This genus is <strong>of</strong>ten found on wood chip (o) paths and<br />
on the forest “floor.” Small peridioles (p) are form<strong>ed</strong> in<br />
the nest-like fruiting body (q).<br />
Of interest . . . many <strong>of</strong> these fungi are important in<br />
forest tree communities in causing the breakdown <strong>of</strong><br />
leaf/twig litter and dead tree branches to form organic<br />
humus (like compost) over the forest floor. This forms a<br />
great substratum for forest tree se<strong>ed</strong> germination and<br />
subsequent development <strong>of</strong> se<strong>ed</strong>lings.<br />
COLOR CODE<br />
tan: peridium (a, b, f, g, q)<br />
green-brown: gleba (h, n)<br />
white: receptacle (i), stalk (j), peridium (k),<br />
periodiole (p)<br />
light pink: stalk (l)<br />
dark pink: receptacle (m)<br />
brown: wood chips (o)
Lichens<br />
A lichen is an association <strong>of</strong> a fungus (mycobiont,<br />
mykes = fungus + bios = life) and an alga (phycobiont,<br />
phykos = alga + bios = life). The fungus is an<br />
ascomycete or a basidiomycete. The algal partner is either<br />
a blue-green or a green alga. The association can<br />
be parasitic, in which the fungus eventually kills the algal<br />
cells; or it can be mutualistic, in which both fungus<br />
and algal cells benefit. Mutual benefits include algal nutrition<br />
that benefits the fungus because <strong>of</strong> the presence<br />
<strong>of</strong> chlorophyll for photosynthesis in the alga. And protection<br />
for the smaller alga is provid<strong>ed</strong> by the fungus.<br />
Lichens can tolerate harsh conditions such as dryness,<br />
arctic cold, and bare rock habitats. They possibly live<br />
for thousands <strong>of</strong> years.<br />
Characteristics. The upper cortex (a) is the outer<br />
protective layer with fungal hyphae gelatiniz<strong>ed</strong> and<br />
cement<strong>ed</strong> together. Next is the algal layer (b). Most lichens<br />
are associat<strong>ed</strong> with the unicellular green alga, Trebouxia.<br />
So far, over 30 genera <strong>of</strong> algae have been found<br />
associat<strong>ed</strong> with lichens. Most <strong>of</strong> the lichen body (thallus)<br />
is made up <strong>of</strong> m<strong>ed</strong>ulla (c) with hyphae loosely interwoven.<br />
The m<strong>ed</strong>ulla retains moisture and stores food.<br />
The thallus may take different forms. Crustose lichens<br />
are extremely flat and only ascocarps (fruiting bodies<br />
<strong>of</strong> the fungus, see 48) may be visible. (See drawing<br />
opposite <strong>of</strong> Graphis scripta). They are found on<br />
rocks and trees. The m<strong>ed</strong>ulla may be emb<strong>ed</strong>d<strong>ed</strong> in<br />
rock surfaces. Foliose lichens have a leafy thallus<br />
and may have a compact<strong>ed</strong> lower cortex (d) and rootlike<br />
anchoring devices call<strong>ed</strong> rhizines (e). (See drawings<br />
opposite <strong>of</strong> Xanthoria and Physcia aipolia.) Fruticose<br />
lichens with three-dimensional projections, call<strong>ed</strong><br />
podetia, arise from a scale-like, loosely-attach<strong>ed</strong> (squamulose)<br />
base. (See drawings opposite <strong>of</strong> Cladonia<br />
cristatella and Cladonia pyxidata.)<br />
Reproduction. Various vegetative structures may be<br />
found on lichens, such as sor<strong>ed</strong>ia and isidia. Sor<strong>ed</strong>ia<br />
originate in the algal layer as masses <strong>of</strong> algae cells with<br />
a few gelatiniz<strong>ed</strong> hyphae erupting through cracks in the<br />
surface cortex. By a process <strong>of</strong> breaking <strong>of</strong>f, new lichen<br />
thalli are form<strong>ed</strong>. An isidium is a projection on a foliose<br />
or fruticose lichen that serves as a vegetative propagule<br />
when broken <strong>of</strong>f. Depending on the type <strong>of</strong> fungus,<br />
fruiting bodies with ascospores or basidiospores are<br />
produc<strong>ed</strong>.<br />
Lichens also have asexual structures call<strong>ed</strong> pycnidia,<br />
flask-shap<strong>ed</strong> structures that produce microconidia. The<br />
54<br />
fungal spore or microconidium must form an association<br />
with an appropriate alga in order to live.<br />
Of interest . . . arctic animal food: Cetrarias, Cladonia<br />
spp. (reindeer mosses), Usneas; human skin rash: Evernias,<br />
Usneas; dye: Letharia, Ochrolechia, Parmelia,<br />
Roccella; ecosystem succession role: lichens are<br />
<strong>of</strong>ten the first colonizers <strong>of</strong> bare substrate, breaking up<br />
rocks, due to their secretions <strong>of</strong> lichen acids; thalli form<br />
an anchor base for later colonizing plants.<br />
Sac Fungi: Euascomycetidae (Lecanorales)<br />
Graphis scripta Script Lichen<br />
Found on hardwood trees, this crustose lichen thallus<br />
(f) has dark eruptions <strong>of</strong> apothecia (g).<br />
Xanthoria<br />
Found on rotten wood, the thallus (h) <strong>of</strong> this foliose<br />
lichen has apothecia compos<strong>ed</strong> <strong>of</strong> gray-green<br />
receptables (i) with brightly color<strong>ed</strong> ascopsore layers<br />
(hymenia, j).<br />
Physcia aipolia Blister Lichen<br />
This foliose lichen has a white-spott<strong>ed</strong> thallus (k) with<br />
apothecia emerging from the surface cortex. The fertile<br />
layer <strong>of</strong> asci (hymenium, l) is gray with a gray-green<br />
receptacle (m).<br />
Cladonia cristatella British Soldiers<br />
The fruticose podetium (n) arises from a squamulose<br />
thallus (o). R<strong>ed</strong> apothecia (p) dot the top <strong>of</strong> the podetia.<br />
Cladonia pyxidata Pyxie Cup<br />
The fruiticose podetia (q) resemble pyxie cups arising<br />
from a squamulose thallus (r). Brown apothecia (s) dot<br />
the cup rims.<br />
COLOR CODE<br />
gray: cortex (a, d), thallus (f), hymenium (l)<br />
green: algae (b)<br />
white: m<strong>ed</strong>ulla (c)<br />
black: rhizines (e), apothecia (g)<br />
gray-green: thallus (h, k, o, r), receptacle (i, m),<br />
podetium (n, q)<br />
yellow-orange: hymenium (j)<br />
r<strong>ed</strong>: apothecium (p)<br />
brown: apothecium (s)
Din<strong>of</strong>lagellates<br />
Fossils <strong>of</strong> din<strong>of</strong>lagellates extend back to the Ordovician<br />
time <strong>of</strong> the Paleozoic. Most are marine.<br />
Characteristics. These microscopic organisms are<br />
unicellular and are usually motile due to the presence<br />
<strong>of</strong> a pair <strong>of</strong> unequal flagella. There are diverse forms.<br />
Nutrition varies from self-fe<strong>ed</strong>ing (autotrophic) tomutually<br />
beneficial (mutualistic) to dependency upon a<br />
host (parasitic). Pigments are chlorophylls a and c,<br />
carotene, and the xanthophyll, peridinin, which gives<br />
a gold-brown color to the organisms. Starch is the primary<br />
stor<strong>ed</strong> food.<br />
The nucleus is large and the chromosomes remain visible<br />
at all stages (see 6), while the nuclear membrane remains<br />
intact. Some din<strong>of</strong>lagellates have light-sensitive<br />
eyespots. Other marine species are bioluminescent:<br />
when cells are vigorously agitat<strong>ed</strong>, they give <strong>of</strong>f flashes<br />
<strong>of</strong> light.<br />
Reproduction. Asexual reproduction occurs by cell division<br />
and cyst formation. Sexual reproduction is by<br />
sex cells (gametes) that look alike (isogamy) or unlike<br />
(anisogamy).<br />
Of interest . . . “blooms” or “r<strong>ed</strong> tides:” under optimal<br />
conditions rapid reproduction produces heavy concentrations<br />
<strong>of</strong> din<strong>of</strong>lagellates that color the ocean r<strong>ed</strong>, r<strong>ed</strong>brown,<br />
or yellow; toxins: these “blooms” can be toxic<br />
55<br />
to other organisms in different ways: killing only fish,<br />
killing mainly invertebrates, or not killing but concentrating<br />
their toxins in bivalve mollusks. The toxins produc<strong>ed</strong><br />
by species <strong>of</strong> Gonyaulax are thousands <strong>of</strong> times<br />
more potent than cocaine, and may cause human death<br />
within 12 hours after consumption <strong>of</strong> affect<strong>ed</strong> bivalves,<br />
but in low concentrations, their toxin usually produce<br />
severe digestive upsets.<br />
Dinophyceae. This class <strong>of</strong> din<strong>of</strong>lagellates is made<br />
up <strong>of</strong> biflagellat<strong>ed</strong> motile cells. One flagellum is coil<strong>ed</strong><br />
around the transverse girdle groove (cingulum), providing<br />
a rotating movement. The other flagellum is locat<strong>ed</strong><br />
in a longitudinal groove (sulcus); it functions as a propellant<br />
from the posterior end.<br />
Gymnodinium<br />
The name means “nak<strong>ed</strong> whorl,” as it is without armor<strong>ed</strong><br />
plates. Structures shown are the girdle groove (a) with<br />
flagellum (b) and the sulcus groove (c) with flagellum<br />
(d). Many chloroplasts (e) are visible.<br />
Ceratium<br />
The name means “horn<strong>ed</strong>.” Armor<strong>ed</strong> plates (f) ornament<strong>ed</strong><br />
with pits cover the organism. Structures shown<br />
are the girdle groove (g) with flagellum (h) and the sulcus<br />
groove (i) with flagellum (j).<br />
COLOR CODE<br />
gold-brown: chloroplasts (e), plates (f)
Golden Algae, Yellow-green<br />
Algae, Diatoms<br />
This diverse group <strong>of</strong> algae has several common features:<br />
a complex carbohydrate food reserve call<strong>ed</strong><br />
chrysolaminaran (leucosin); more carotene pigments<br />
than chlorophylls, thus the gold and yellow-green colors;<br />
and chlorophylls a and c. The pigment, fucoxanthin,<br />
occurs in some <strong>of</strong> the divisions. Forms range from<br />
amoeboid cells, flagellat<strong>ed</strong> cells, filaments, to parenchymatous<br />
thalloid types.<br />
Golden Algae (Chrysophyceae). Members in this<br />
group live mainly in fresh water. There are a few marine<br />
forms. Some have cell coverings that may contain<br />
silica. Two-part resting spores (statocysts) are form<strong>ed</strong><br />
when unfavorable conditions occur. Asexual reproduction<br />
is by fragmentation and production <strong>of</strong> an asexual<br />
reproductive cell (zoospore). Sexual reproduction is not<br />
well-known.<br />
Dinobryon<br />
This fresh water alga forms free-swimming colonies <strong>of</strong><br />
biflagellat<strong>ed</strong> cells. The protoplast (a) is connect<strong>ed</strong> by<br />
a thin strand to its protective covering: a transparent,<br />
open-end<strong>ed</strong>, vase-shap<strong>ed</strong> lorica (b). The protoplast has<br />
2 flagella (c) <strong>of</strong> unequal length, an eyespot (d) and a<br />
chloroplast (e).<br />
Yellow-green Algae (Xanthophyceae). Fresh water<br />
habitats are typical for this group. They form a scum<br />
in standing water, and some occur on the surface <strong>of</strong><br />
moist mud and on tree trunks. There are less than 100<br />
known species.<br />
Vaucheria<br />
This alga is a branching filament (f) containing many<br />
chloroplasts (g). It may form mats under moist, greenhouse<br />
clay pots. The filament has no cross-walls except<br />
where reproductive chambers are form<strong>ed</strong>. Reproduction<br />
is by asexual zoospores and by the sexual union<br />
<strong>of</strong> a small motile sperm with a large non-motile egg<br />
(oogamy). An antheridial branch (h) containing sperm<br />
cells (i) forms laterally on a filament. A biflagellat<strong>ed</strong><br />
sperm cell swims to a pore (j) in the oogonium (k) to<br />
fertilize the egg (l). The fertiliz<strong>ed</strong> egg develops into an<br />
oospore (m), which remains in the oogonium as a resting<br />
spore until germination occurs.<br />
56<br />
Diatoms (Bacillariophyceae). Two hundr<strong>ed</strong> surviving<br />
genera <strong>of</strong> unicellular diatoms are known, with as many<br />
as 100,000 species. Diatom walls (frustules) have the<br />
structure <strong>of</strong> a narrow box with a lid. The lid, call<strong>ed</strong> the<br />
epivalve, fits over the box or hypovalve. The overlapping<br />
area is the girdle region. Reproduction is by cell division.<br />
It involves separation <strong>of</strong> the epivalve and hypovalve,<br />
with new, smaller container walls being form<strong>ed</strong>. When<br />
an ultimate, minimum size r<strong>ed</strong>uction is reach<strong>ed</strong>, new<br />
cells are form<strong>ed</strong> by the fusion <strong>of</strong> the protoplasm <strong>of</strong> two<br />
cells. Diatoms also have sexual reproduction.<br />
Of interest . . . ecosystem: diatoms, the major component<br />
<strong>of</strong> plankton—which form the base <strong>of</strong> aquatic food<br />
chains, are the single most important group <strong>of</strong> algae.<br />
In relation to other families, diatoms also supply the<br />
major percentage <strong>of</strong> the world’s oxygen supply. They<br />
are affect<strong>ed</strong> by temperature, pollution, and light. Some<br />
characteristic species <strong>of</strong> diatoms and other algae are<br />
indicators <strong>of</strong> pollut<strong>ed</strong> water, while other species are indicative<br />
<strong>of</strong> clean, non-pollut<strong>ed</strong> water; fossils: diatomaceous<br />
earth is represent<strong>ed</strong> by the silica remains <strong>of</strong> diatoms;<br />
it is us<strong>ed</strong> for filters, abrasives, insulation, in pavement<br />
paints, and as an indicator <strong>of</strong> oil- and gas-bearing<br />
formations.<br />
Pinnularia<br />
The epivaluve (n) portion fits over the hypovalve (o) as<br />
shown in this diatom diagram.<br />
Asterionella<br />
This diatom forms a star-shap<strong>ed</strong> colony <strong>of</strong> cells (p).<br />
Coscinodiscus<br />
Surface striations (q) <strong>of</strong> puncture holes mark the wall<br />
(r).<br />
COLOR CODE<br />
r<strong>ed</strong>: eyespot (d)<br />
yellow: protoplast (a), diatoms (n, o, p, q, r)<br />
yellow-brown: chloroplast (e)<br />
yellow-green: filament (f), oospore (m)<br />
tan: sperm cells (i), egg (l)
R<strong>ed</strong> Algae<br />
The r<strong>ed</strong> algae, with about 400 genera, are mostly marine<br />
with only a few known freshwater genera. Most are<br />
found in tropical areas where they occur at great depths<br />
or along intertidal regions.<br />
Characteristics. Their color varies greatly depending<br />
on the amount <strong>of</strong> pigments and can range from shades<br />
<strong>of</strong> green, r<strong>ed</strong>-brown, bright r<strong>ed</strong>, blue, and purple-blue to<br />
black. Usually, the green pigments, chlorophylls a and<br />
d, are mask<strong>ed</strong> by the phycobilin pigment (r<strong>ed</strong> phycoerthyrin<br />
and blue phycocyanin). Other pigments include<br />
carotenes and xanthophylls (see 4).<br />
R<strong>ed</strong> algae are relatively simple vegetative organisms<br />
but have complex reproductive systems. The primary<br />
food reserve is floridean starch (a polysaccharide =<br />
carbohydrate made up <strong>of</strong> many glucose units). There<br />
are a few microscopic unicellular forms, but most have<br />
branch<strong>ed</strong> filaments or flat leaf-like forms.<br />
Reproduction. Asexual reproduction occurs by fragmentation<br />
and production <strong>of</strong> vegetative spores. R<strong>ed</strong> algae<br />
are divid<strong>ed</strong> into two subclasses. In the more primitive<br />
Bangiophycidae, sexual reproduction is mostly absent.<br />
In the more advanc<strong>ed</strong> Florideophycidae, sexual<br />
reproduction is oogamous: non-flagellat<strong>ed</strong> male gametes<br />
(spermatia) are carri<strong>ed</strong> by water to a stationary<br />
female gamete-bearing structure call<strong>ed</strong> the carpogonium.<br />
Of interest . . . colloids: Chondrus crispus (carrageenan,<br />
us<strong>ed</strong> as a stabilizing agent in milk products,<br />
jelli<strong>ed</strong> foods, cosmetics, insect sprays, and water-bas<strong>ed</strong><br />
paints), Gloiopeltis (funori, us<strong>ed</strong> as a water-soluble<br />
sizing in water-bas<strong>ed</strong> paints and as a flexible starch in<br />
laundering); agar: Gelidium (agar, us<strong>ed</strong> as a culture<br />
m<strong>ed</strong>ium in microbiology, as non-irritant bulk in human<br />
intestinal disorders, and to make pill capsules); coral<br />
57<br />
reefs: Corallinna, Lithothamnium, and Galaxaura<br />
accumulate calcium carbonate, which contributes to<br />
reef-building; ecosystem: r<strong>ed</strong> algae provide food for<br />
marine animals; human food: Chrondrus crispus (Irish<br />
moss), Porphyra (nori), Palmaria (dulse).<br />
Porphyra Nori<br />
This genus, in the subclass Bangiophycidae, has a leafy<br />
thallus (a) with rhizoidal cells at the base for attachment<br />
to rocks.<br />
Polysiphonia<br />
Plac<strong>ed</strong> in the subclass Florideophycidae, this genus<br />
has a filamentous thallus (b) construct<strong>ed</strong> <strong>of</strong> many (poly)<br />
tubes (siphons, c); hence its name. Male gametophyte<br />
individuals produce special branchlets call<strong>ed</strong> trichoblasts<br />
(d), that bear spermatia (e). Female gametophyte<br />
individuals produce urn-shap<strong>ed</strong> structures call<strong>ed</strong><br />
cystocarps (f), which contain egg cases (carpogonia).<br />
After fertilization and maturation, carpospores (g) are<br />
releas<strong>ed</strong>. Carpospores develop into a tetrasporophyte<br />
generation, producing tetraspores that germinate into<br />
male or female gametophytes (gamete-bearing). Both<br />
the tetrasporophyte and the gametophyte generations<br />
have the same external filamentous appearance.<br />
Of interest ...to preserve filamentous marine plant<br />
specimens, place the plant in a large shallow pan <strong>of</strong><br />
water and allow it to float naturally. Then slide art paper,<br />
bond paper, or, ideally, rag paper under the specimen.<br />
Slowly lift the paper with the plant on top and drain excess<br />
water <strong>of</strong>f one end. Blot the bottom <strong>of</strong> the paper on<br />
newsprint, then place plant-on-paper in a single fold<strong>ed</strong><br />
sheet <strong>of</strong> newspaper. Stack with blotters and newspaper<br />
and press with weights or place in a plant press<br />
until dry.<br />
COLOR CODE<br />
r<strong>ed</strong>-purple: thallus (a)<br />
r<strong>ed</strong>: thallus (b), tubes (c), trichoblast (d, e),<br />
cystocarp (f), carpospores (g)
Green Algae<br />
Green algae constitute a very ancient group <strong>of</strong> plants<br />
with fossils occurring back to early periods <strong>of</strong> the Paleozoic<br />
era. They are mainly freshwater plants, but<br />
also occur in saltwater, in soil, on tree bark, and on<br />
snow.<br />
Characteristics. Green algae forms are unicellular,<br />
colonial, filamentous, membranous (resembling)<br />
leaves), and tubular. The cells have many <strong>of</strong> the<br />
organelles found in cells <strong>of</strong> higher plants, including<br />
a rigid cell wall; a nucleus with one or more nucleoli;<br />
a large vacuole; well-organiz<strong>ed</strong> chloroplasts;<br />
pigments <strong>of</strong> chlorophylls a and b, carotenes, and<br />
xanthophylls; self-fe<strong>ed</strong>ing nutrition (autotropic); and<br />
pyrenoids associat<strong>ed</strong> with starch formation. Motile<br />
forms usually have two whiplash flagella <strong>of</strong> equal length.<br />
There are many varying types <strong>of</strong> asexual and sexual<br />
reproduction.<br />
Of interest . . . phylogeny: green algae are consider<strong>ed</strong><br />
to be on the direct evolutionary line to higher vascular<br />
plants; ecosystem: they contribute to the freshwater<br />
plankton <strong>of</strong> the food chain.<br />
Note: Of the 450 genera, the few illustrat<strong>ed</strong> here are<br />
microscopic, with the exception <strong>of</strong> Acetabularia, which<br />
is macroscopic.<br />
Chlamydomonas<br />
This unicellular alga is motile by means <strong>of</strong> two flagella<br />
(a). The cup-shape chloroplast (b), that contains a r<strong>ed</strong><br />
eyespot (c) and a pyrenoid (d), surrounds the nucleus<br />
(e).<br />
Eudorina<br />
Sixteen cells make up this coenobium (a colony<br />
<strong>of</strong> a fix<strong>ed</strong> number <strong>of</strong> cells). A gelatinous sheath (f)<br />
58<br />
surrounds the flagellat<strong>ed</strong> (g) cells. The chloroplast (h)<br />
contains an eyespot (i).<br />
Cladophora<br />
This alga has branch<strong>ed</strong> filaments whose cells contain<br />
numerous pyrenoids (j) in reticulate chloroplasts (k).<br />
Acetabularia<br />
This marine alga, known as “mermaid’s wineglass,” is<br />
one immense cell with a giant nucleus (l) in the basal<br />
rhizoid (m). The nucleus migrates to the cap (n) where<br />
reproductive cysts are form<strong>ed</strong>.<br />
Scen<strong>ed</strong>esmus<br />
This is a coenobium compos<strong>ed</strong> <strong>of</strong> four cells that are<br />
join<strong>ed</strong> laterally. The laminate chloroplast (o) contains a<br />
pyrenoid (p). There is one nucleus (q) per cell.<br />
Micrasterias<br />
The cell wall, enclos<strong>ed</strong> by a gelatinous sheath (r), is divid<strong>ed</strong><br />
into two halves. Each half <strong>of</strong> this unicellular alga<br />
has a chloroplast (s) with pyrenoids (t). The nucleus is<br />
locat<strong>ed</strong> at the contraction (isthmus, u) between the cell<br />
halves. For asexual propagation, the nucleus divides in<br />
half, the cell splits into two halves and separates. Then<br />
each half grows a new partner to form a cell as illustrat<strong>ed</strong>.<br />
This plant occurs in freshwater ponds and lakes.<br />
Spirogyra<br />
Spirogyra is an unbranch<strong>ed</strong> filamentous freshwater<br />
alga. One cell in a filament is shown. It has two spiral<br />
chloroplasts (v) with numerous pyrenoids (w). The<br />
nucleus (x) is suspend<strong>ed</strong> in the center by threads <strong>of</strong><br />
cytoplasm.<br />
COLOR CODE<br />
colorless: flagellum (a, g), sheath (f, r), rhizoid (m)<br />
white: pyrenoid (d, j, p, t, w)<br />
gray: nucleus (e, l, q, u, x)<br />
r<strong>ed</strong>: eyespot (c, e, i)<br />
green: chloroplast (b, h, k, o, s, v), cap (n)
Brown Algae<br />
The algae in this division are mainly marine. They<br />
live along cooler coastal, intertidal areas, forming large<br />
b<strong>ed</strong>s <strong>of</strong> brown seawe<strong>ed</strong>. Common features among the<br />
different genera are the pigments <strong>of</strong> chlorophylls a and<br />
c, β-carotene, violaxanthin and fucoxanthin, source <strong>of</strong><br />
the brown color; a sugar food reserve (laminarin); and<br />
cell walls made up <strong>of</strong> an inner cellulose layer and an<br />
outer mucilaginous layer. Diverse size ranges from microscopic<br />
to enormous kelps up to 60 meters in length.<br />
Of the 250 known genera there are more than 900<br />
species.<br />
Asexual reproduction occurs by fragmentation and production<br />
<strong>of</strong> sporangia with zoospores. When a section<br />
<strong>of</strong> a living filament breaks <strong>of</strong>f, the fragment becomes a<br />
new individual. A sporophyte individual produces sporangia<br />
with zoospores, that when releas<strong>ed</strong>, develop into<br />
more sporophyte individuals.<br />
Sexual reproduction is by sex cells (gametes) that<br />
look alike (isogamy), or are unlike (anisogamy),<br />
or by formation <strong>of</strong> motile sperm with a stationary<br />
egg (oogamy).<br />
Of interest . . . ecosystem: dense b<strong>ed</strong>s <strong>of</strong> kelp along<br />
sea coasts provide a substrate for small animals, protection,<br />
and foods for swimming animals and fish, and<br />
they contribute to phytoplankton communities; industry:<br />
algin (a cell wall constituent) contains sodium, ammonium<br />
and potassium salts (these salt compounds<br />
are us<strong>ed</strong> in firepro<strong>of</strong>ing fabrics, as laundry starch substitutes,<br />
as ice cream stabilizers, as binders in printer’s<br />
ink, in soaps and shampoos, in photographic film coatings,<br />
in paints and varnishes, and in leather finishes;<br />
insecticides; toothpaste, shaving cream, and lipstick);<br />
fertilizer: brown algal organisms contain more potassium,<br />
less phosphorus, and about the same proportion<br />
59<br />
<strong>of</strong> nitrogen as animal manure; food: species <strong>of</strong> kelps<br />
are us<strong>ed</strong> as food (lombu) in Japan.<br />
Ectocarpales. Of the 13 orders, the most primitive<br />
brown algae are found in this order. The body (thallus)<br />
consists <strong>of</strong> erect filaments <strong>of</strong> a single row <strong>of</strong> cells (uniseriate)<br />
with basal branching systems (heterotrichy).<br />
Their size ranges from microscopic to forms up to<br />
25 cm. long.<br />
Ectocarpus<br />
This alga is found on most seashores growing upon<br />
other plants (epiphytic). The filaments (a, b) <strong>of</strong> the alga<br />
have a filmy appearance. The cells have net-like (reticulate)<br />
chlorophasts (c). Alternate generations are represent<strong>ed</strong><br />
by sporophytes and male and female gametophytes.<br />
A sporophyte is an individual that produces<br />
sporangia with 2n spores, while a gametophyte produces<br />
1n gametes (sex cells).<br />
The sporophyte produces two types <strong>of</strong> reproductive<br />
structures: (1) a muticellular (plurilocular) sporangium<br />
(d) produces 2n zoospores that germinate into another<br />
sporophyte plant; (2) a unicellular (unilocular) sporangium<br />
(e) produces 1n zoospores that germinate into<br />
gametophytes. Gametophytes develop plurilocular gametangia<br />
(f) that produce motile gametes <strong>of</strong> the same<br />
sex as that <strong>of</strong> the parent. Fusion <strong>of</strong> male and female<br />
gametes results in development <strong>of</strong> a 2n (diploid) sporophyte.<br />
If a gamete does not fuse with another gamete, it may be<br />
by parthenogenic germination produce a 1n (haploid)<br />
sporophyte. Parthenogenesis is the development <strong>of</strong> a<br />
new individual from an unfertiliz<strong>ed</strong> egg. There are also<br />
other more complicat<strong>ed</strong> variations in the life cycle <strong>of</strong><br />
Ectocarpus.<br />
COLOR CODE<br />
tan-green: sporophyte (a), filament (b), chloroplasts<br />
(c)<br />
tan: sporangium (d, e), gametangium (f)
Brown Algae (continu<strong>ed</strong>)<br />
Laminariales (Kelps). This order consists <strong>of</strong> the kelps,<br />
the largest <strong>of</strong> all algae. Some reach 100 meters or more<br />
in length. The microscopic gametophytes have male<br />
and female gametes on separate individuals. The characteristic<br />
tissue <strong>of</strong> the sporophyte is compos<strong>ed</strong> <strong>of</strong> randomly<br />
arrang<strong>ed</strong> cells (parenchyma, for photosynthesis<br />
and food storage), rather than a continuous filament <strong>of</strong><br />
cells.<br />
Well-develop<strong>ed</strong> meristems generate new cells that contribute<br />
to growth <strong>of</strong> the sporophyte thallus in length and<br />
width. (Meristems are areas <strong>of</strong> undifferentiat<strong>ed</strong> cells<br />
that can develop into specializ<strong>ed</strong> tissues and organs.)<br />
The macroscopic sporophyte structure consists <strong>of</strong> a<br />
blade, stalk (stipe), and holdfast part that is attach<strong>ed</strong><br />
to the rocky substrate.<br />
Laminaria<br />
Most species in this genus have perennial basal structures<br />
consisting <strong>of</strong> a stipe (a) and a root-like holdfast (b).<br />
There is a loss, but later replacement, <strong>of</strong> the sporopyte<br />
blade (c) from the stipe’s meristematic region.<br />
The reproductive structures <strong>of</strong> the sporophyte are<br />
asexual unilocular sporangia (d) containing zoospores<br />
(e). Between the sporangia are thread-like structures<br />
term<strong>ed</strong> paraphyses (f), with distend<strong>ed</strong> tips that provide<br />
protection for the zoospores.<br />
Nereocystis leutkeana Ribbon Kelp<br />
This annual kelp has blades that develop in the same<br />
manner as Laminaria. Due to progressive splitting, the<br />
blade (g) appears ribbon-like. The top <strong>of</strong> the stipe (h)<br />
bloats into a gas-fill<strong>ed</strong> pneumatocyst (i), which serves<br />
as a float to maintain the buoyancy <strong>of</strong> the blades at the<br />
water’s surface as the stipe elongates.<br />
Sexual reproduction is oogamous as follows: the microscopic<br />
male gametophyte produces clusters <strong>of</strong> antheridia<br />
(k) containing biflagellat<strong>ed</strong> sperm at the filament<br />
tips. The microscopic female gametophyte produces<br />
a non-motile egg in the oogonium (l). After fertilization,<br />
a zygote is form<strong>ed</strong> which emerges from the<br />
oogonium and begins sporophyte development (m). (A<br />
zygote is the product <strong>of</strong> fertilization and is potentially a<br />
new individual.)<br />
60<br />
COLOR CODE<br />
tan-green: stipe (a), blade (c)<br />
tan: holdfast (b), sporangium (d),<br />
zoospores (e), antheridium (k)<br />
white: paraphysis (f)<br />
yellow-brown: blade (g), stipe (h), pneumatocyst (i),<br />
sporophyte (m)<br />
brown: holdfast (j)<br />
transparent: empty oogonium (l)
Brown Algae (continu<strong>ed</strong>)<br />
Fucales. The algae in this order are unique in that the<br />
gametophyte generation has been suppress<strong>ed</strong>. Thus,<br />
there is only a 2n (diploid) organism. It has oogamous<br />
sexual reproduction by 1n (haploid) gametes (see below),<br />
which arise by meiosis. Meiosis is a process <strong>of</strong><br />
sexual reproduction in which a 2n (diploid) organism<br />
produces 1n (haploid) sex cells (gametes) by r<strong>ed</strong>uction<br />
division from one 2n cell to form four 1n cells.<br />
Fucus vesiculosus<br />
The thallus <strong>of</strong> this alga consists <strong>of</strong> a holdfast, stipe (a),<br />
and flat, bilaterally branch<strong>ed</strong> blades (b) with midrib (c)<br />
and pair<strong>ed</strong> air bladders (pneumatocysts, d). The separate<br />
male and female plants have swollen fertile areas<br />
on the blade tips call<strong>ed</strong> receptacles (e). They produce<br />
either male or female conceptacles (f).<br />
A conceptacle has a pore (g) that opens from the<br />
surface <strong>of</strong> the receptacle to surrounding water. Also<br />
present in the conceptacle are sterile, hair-like threads<br />
call<strong>ed</strong> paraphyses (h), and either oogonia (i) that produce<br />
eggs, or antheridia (j), that produce biflagellat<strong>ed</strong><br />
sperm. When eggs are releas<strong>ed</strong> from the oogonium<br />
into the water, they produce fucoserraten, asexattractant<br />
(pheromone), that causes the sperm to swarm<br />
around them. Fertiliz<strong>ed</strong> eggs develop into 2n (diploid)<br />
individuals.<br />
61<br />
COLOR CODE<br />
brown-r<strong>ed</strong>: stipe (a), blade (b, c)<br />
tan: air bladders (d)<br />
brown: receptacle (e), oogonium (i),<br />
antheridium (j)<br />
colorless: conceptacle wall (f), paraphysis (h)
Stoneworts<br />
According to the fossil record, this ancient group <strong>of</strong> 6<br />
living genera lies developmentally between the green<br />
algae and the liverworts and mosses (bryophytes). Fossils<br />
<strong>of</strong> stoneworts are found from the late Silurian period,<br />
over 400 million years ago. Stoneworts grow submerg<strong>ed</strong><br />
in fresh water or sometimes in brackish (salty)<br />
water with rhizoidal attachment to the substrate <strong>of</strong> either<br />
soil or rock. With a preference for hard water (high pH),<br />
stoneworts have incrustations <strong>of</strong> calcium carbonate that<br />
account for the “stonewort” name. An obnoxious odor<br />
is characteristic <strong>of</strong> the plants.<br />
Stoneworts grow continuously by means <strong>of</strong> a single<br />
dome-shap<strong>ed</strong> apical cell that cuts <strong>of</strong>f by mitotic divisions<br />
new node and internodal cells.<br />
Their pigments are chlorophylls a and b, carotenes, and<br />
xanthophylls. Sexual reproduction is oogamous, which<br />
means a motile sperm unites with a larger, stationary<br />
egg.<br />
Chara Stonewort<br />
The base <strong>of</strong> this plant, the protonema (a), has<br />
substrate-anchoring rhizoids (b), while the upper portion<br />
<strong>of</strong> the stem (c) has whorls <strong>of</strong> branches (d) at the<br />
nodes. The stem is a long axis <strong>of</strong> cells divid<strong>ed</strong> into<br />
small regions (nodes and internodes). The node divides<br />
producing whorls <strong>of</strong> branches. The internode is made<br />
up <strong>of</strong> one cell containing a single nucleus. The repro-<br />
62<br />
ductive structures, male globules and female nucules<br />
(e), arise at nodes on the branches.<br />
The male globule (antheridium) has an outer layer <strong>of</strong><br />
sterile shield cells (f). Small cells (g) arise on the inner<br />
surface which produce antheridial filaments (h). Each<br />
cell in the filament produces a single sperm with two<br />
flagella for motility. The shield cells break open, permitting<br />
sperm cells to swim free.<br />
The female nucule (oogonium) is attach<strong>ed</strong> to a node<br />
by a short stalk-like cell (i). Sterile sheath cells (j) spiral<br />
around the single egg (k). At the top are small coronal<br />
cells (l). At maturity, slits that form under the coronal<br />
cells allow the sperm to enter the oogonium.<br />
After fertilization, the sheath cells thicken around the zygote<br />
(oospore), which overwinters as a dormant structure.<br />
After germination in the spring, the zygote wall<br />
splits and the primary protonema (m) emerges to form<br />
a new sporophyte plant.<br />
Of interest . . . gravisensors: barium sulfate crystals in<br />
the tips <strong>of</strong> the rhizoids s<strong>ed</strong>iment in the gravitational field,<br />
thus enabling the rhizoids to respond to gravity and<br />
bend downward towards the substratum (starch-fill<strong>ed</strong><br />
amyloplasts in root caps <strong>of</strong> higher plants serve the same<br />
function). The large cells <strong>of</strong> stoneworts have proven to<br />
be highly suitable for experimental study <strong>of</strong> patterns<br />
<strong>of</strong> cell growth, orientation <strong>of</strong> cell wall micr<strong>of</strong>ibrils, transport<br />
<strong>of</strong> ions into and out <strong>of</strong> the cells, and cytoplasmic<br />
streaming (cyclosis).<br />
COLOR CODE<br />
gray-green: protonema (a, m), stem internode (c),<br />
branches (d)<br />
white: rhizoid (b)<br />
r<strong>ed</strong>: nucules (e), sheath cells (j)<br />
tan: egg (k), coronal cells (l)<br />
colorless: shield cells (f), filaments (h)<br />
r<strong>ed</strong>-brown: cells (g)<br />
green: stalk cell (i)
Liverworts, Hornworts, Mosses<br />
This most primitive group <strong>of</strong> green land plants are call<strong>ed</strong><br />
bryophytes. Mostly perennials, the plants are small in<br />
size and have no vascular tissues. Humid habitats provide<br />
a water m<strong>ed</strong>ium for the motile (flagellat<strong>ed</strong>) sperm<br />
to reach the egg. Bryophytes cannot tolerate salt water,<br />
excessive heat, or pollution. Mosses can dry down<br />
during drought, then recover with rainfall. They are also<br />
tolerant <strong>of</strong> freezing. Liverworts, on the other hand, cannot<br />
tolerate dryness, but can survive freezing.<br />
Bryophytes have two generations. The dominant plant<br />
(gametophyte generation) develops from a 1n (haploid)<br />
spore and produces sperms and eggs. A fertiliz<strong>ed</strong> egg<br />
forms a 2n zygote, which develops into the sporophyte.<br />
The smaller sporophyte generation produces 1n spores<br />
by meiosis that are dispers<strong>ed</strong> and develop into gametophytes.<br />
In some bryophytes, asexual structures call<strong>ed</strong><br />
gemmae cups (a) contain gemmae (b) that develop<br />
into gametophytes.<br />
Liverworts (Hepaticae). The liverworts are primitive<br />
bryophytes. The gametophyte is flat and strap-shap<strong>ed</strong>,<br />
as in Marchantia, or leafy as in Bazzania. The gametophyte<br />
body (thallus, c) branches equally (dichotomously).<br />
Marchantia polymorpha<br />
This species has unisexual thalli (dioecious). The male<br />
gametophyte develops antheridia-bearing stalks (antheridiophores,<br />
d), which produce motile sperm in<br />
its disc-shap<strong>ed</strong> top. The female gametophyte develops<br />
an archegoniophore (e), which produces archegonia,<br />
flask-shap<strong>ed</strong> structures containing eggs, under its<br />
umbrella-shap<strong>ed</strong> top. After fertilization, a 2n zygote develops<br />
into a sporophyte, which in turn produces spores<br />
that develop into gametophytes.<br />
Hornworts (Anthocerotae)<br />
Anthoceros punctata Common Hornwort<br />
The gametophyte thallus (f) forms a flat rosette. Male<br />
and female structures occur in the upper layers <strong>of</strong> the<br />
thallus. The union <strong>of</strong> sperm and egg produces the<br />
sporophyte. A foot (g) secures the sporophyte (h), to<br />
the gametophyte thallus. The sporophyte splits at the<br />
top into 2 valves to expose the spores.<br />
Mosses (Musci). All moss gametophytes have 3- to<br />
5-rank<strong>ed</strong> leaves. Most mosses develop from a spore<br />
63<br />
into a thread-like structure (protenema) with rhizoids,<br />
then into a leafy gametophyte. The young sporophyte<br />
is green and photosynthetic. Its firm tissue eventually<br />
turns brown and may persist on the gametophyte for<br />
years. Unlike the liverworts and hornworts, mosses<br />
show a great deal <strong>of</strong> variation in gametophytes and<br />
sporophytes. Mosses form large colonies by fragmentation<br />
and gemmae.<br />
Sphagnum centrale Peat Moss<br />
The peat mosses (Sphagnum, i) grow in acid bogs. They<br />
secrete hydrogen ions, contributing to the acidity. This<br />
acid environment delays the vegetation decay process.<br />
Thus, sphagnum mosses contribute to mat formation<br />
at the open water margin <strong>of</strong> the bog. This provides a<br />
habitat for other types <strong>of</strong> plants. Undisturb<strong>ed</strong>, a bog<br />
can eventually develop into a forest through the process<br />
<strong>of</strong> succession. Due to its great water-holding capacity<br />
Sphagnum peat, deriv<strong>ed</strong> from old bogs, is add<strong>ed</strong> to<br />
garden soil to acidify it and hold moisture.<br />
Andrea rupestris Rock-loving Moss<br />
This plant is found mainly on rocky outcroppings. The<br />
leafy gametophyte (j) is branch<strong>ed</strong>. The sporophyte is<br />
rais<strong>ed</strong> on a stalk (pseudopodium, k). When the capsule<br />
(l) dries the inner walls contract into 4 slits, releasing<br />
the spores.<br />
Tetraphis pellucida Four-tooth Moss<br />
Moist rotting logs in coniferous forests provide the<br />
main habitat for this plant. Leafy gametophytes (m),<br />
attach<strong>ed</strong> by rhizoids (n), produce gemmae cups (o).<br />
The sporophyte is borne on a long stalk (seta, p),<br />
that twists near the capsule (q). A pleat<strong>ed</strong> covering<br />
(calyptra, r) protects the capsule; it falls <strong>of</strong>f at maturity.<br />
A lid (operculum) opens to expose 4 teeth (peristome,<br />
s). When wind or animals shake the capsules, spores<br />
are releas<strong>ed</strong>.<br />
COLOR CODE<br />
green: gemma cups (a, o), gemmae (b), thallus<br />
(c,j,m)<br />
tan: antheridiophore (d), archegoniophore<br />
(e), foot (g), pseudopodium (k), capsule<br />
(l, q), seta (p), calptra (r), teeth (s)<br />
black: sporophyte (h)<br />
gray-green: thallus (i)<br />
white: rhizoids (n)
Whisk Ferns<br />
The whisk ferns are believ<strong>ed</strong> to be among the most<br />
ancient <strong>of</strong> living vascular plants. There is no known<br />
fossil record to determine relationships with extinct<br />
forms. There are two psilophyte genera: Psilotum and<br />
Tmesipteris.<br />
Characteristics. These are rootless, simple plants<br />
with rhizoids, as anchoring structures, and hairless<br />
(glabrous) upright stems with simple sterile appendages<br />
(enations). The large spore cases (sporangia)<br />
are fus<strong>ed</strong> into two’s or three’s.<br />
Reproduction. In whisk ferns, an alternation <strong>of</strong> generations<br />
results in a dominant sporophyte plant producing<br />
alike spores (homosporous), which germinate to form<br />
1n (haploid) gametophytes. The underground gametophyte,<br />
which forms mycorrhizal associations with fungi<br />
for nutrition, develops archegonia, each with 1 egg, and<br />
antheridia with flagellat<strong>ed</strong> sperm.<br />
After fertilization, a 2n (dipoid) zygote forms, which<br />
eventually develops into a sporophyte plant. Asexual reproductive<br />
bodies (gemmae) may be produc<strong>ed</strong> on the<br />
sporophyte.<br />
Of interest . . . Whisk ferns are dominant components <strong>of</strong><br />
the tropical ecosystems <strong>of</strong> Hawaii’s island archipelago.<br />
In fact, they are consider<strong>ed</strong> to be we<strong>ed</strong>s in Hawaii due<br />
to their propensity to colonize disturb<strong>ed</strong> areas, (W. H.<br />
Wagner, Jr., personal communication).<br />
Psilotum nudum Whisk Fern<br />
This plant may be terrestrial or grow upon other plants<br />
(epiphytic) in the tropics and subtropics. The shoot is<br />
upright with stems (a) that branch into two equal parts<br />
(dichotomous branching). Simple leaf-like appendages,<br />
call<strong>ed</strong> enations (b), emerge from the stem. The threelob<strong>ed</strong><br />
spore case (c) has a small, fork<strong>ed</strong>, leaf-like scale<br />
(d) below.<br />
Tmsipteris tannensis var. lanceolata<br />
This plant is found only in the southwestern Pacific<br />
Ocean area. It has a simple stem (e) with flat, singlevein<strong>ed</strong>,<br />
leaf-like appendages (f). The sporangium (g) is<br />
two-lob<strong>ed</strong>.<br />
64<br />
COLOR CODE<br />
light green: stem (a), enations (b), scale (d)<br />
yellow: sporangium (c)<br />
green: stem (e), enations (f)<br />
tan: sporangium (g)
Clubmosses, Spikemosses,<br />
Quillworts<br />
This distinct group <strong>of</strong> ancient plants has five living<br />
genera. Common features are single-vein<strong>ed</strong> leafy appendages<br />
(microphylls), two-part branching which<br />
may be equal or unequal, axillary sporecases (sporangia),<br />
and flagellat<strong>ed</strong> sperm.<br />
Clubmosses (Lycopodiales). Lycopodium, with 700<br />
species, is found worldwide, with most species occuring<br />
in the tropics. Plants are herbaceous, perennial,<br />
and usually evergreen. No leaf outgrowths (liguIes)<br />
are present. Some species bear sporangia in terminal<br />
spikes (strobili).<br />
Lycopodium annotinum Stiff Clubmoss<br />
The creeping horizontal stem (rhizome) <strong>of</strong> this plant has<br />
upright shoots with annual constrictions (a). The spirally<br />
arrang<strong>ed</strong> leaves (b) are narrow and spread in different<br />
directions. In the alternation <strong>of</strong> generations, the<br />
spore germinates into a plant (gametophyte) bearing<br />
male and female sex cells (gametes). Then, after fertilization,<br />
an embryo develops into a sporophyte, the<br />
dominant plant.<br />
A “cone” (strobilus, c) <strong>of</strong> specializ<strong>ed</strong> leaves (sporophylls),<br />
bearing sporangia in the axils, terminates an<br />
upright shoot. The sporangia contain one type <strong>of</strong> spore<br />
(homosporous).<br />
Spikemosses (Selaginellales). Selaginella, the single<br />
genus, has about 600 species. Differing from<br />
Lycopodium, there are ligules, root-like organs<br />
(rhizophores) occurring at dichotomies, and sporangia<br />
always in a “cone,” bearing spores <strong>of</strong> two sizes<br />
(heterosporous). Reproduction is the same as shown<br />
below for Isoetes.<br />
While most species prefer moist conditions, there is<br />
an unusual species, Selaginella lepidophylla which is<br />
call<strong>ed</strong> resurrection plant. It is native to dry regions <strong>of</strong><br />
the southwestern Unit<strong>ed</strong> States and Mexico. Dry specimens<br />
<strong>of</strong> this plant are occasionally found in plant stores<br />
as a curiousity because it appears as a dri<strong>ed</strong> leafy mass<br />
until “reviv<strong>ed</strong>” with water that causes it to turn green<br />
and flatten into a rosette. It can be dri<strong>ed</strong> and reviv<strong>ed</strong><br />
repeat<strong>ed</strong>ly.<br />
65<br />
Selaginella rupestris Rock Spikemoss<br />
The creeping stem has spirally arrang<strong>ed</strong> leaves (d),<br />
root-like appendages (rhizophores, e), and 4-sid<strong>ed</strong> fertile<br />
spikes (f).<br />
Quillworts (Isoetales). These plants are consider<strong>ed</strong><br />
by some botanists to be the last remnant <strong>of</strong> the fossil<br />
tree lycopods due to their peculiar secondary growth,<br />
heterospory and presence <strong>of</strong> ligules. Isoetes, with 60<br />
species, grows mostly submerg<strong>ed</strong> in lakes, ponds, and<br />
streams.<br />
Isoetes echinospora Braun’s Quillwort<br />
The sporophyte has an enlarg<strong>ed</strong> perennial underground<br />
stem, the corm (g). The roots (h) branch dichotomously,<br />
and annual strap-shap<strong>ed</strong> leaves (i) grow<br />
in a spiral cluster (rosette). The leaf has a ligule (j), 4<br />
vertical air chambers (k), and an expand<strong>ed</strong> fertile base<br />
cover<strong>ed</strong> by a flap (velum, l).<br />
At the bases heterosporous leaves (mega- and microsporophylls)<br />
bear megasporangia (m) containing<br />
large spores (megaspores, n) or microsporangia (o)<br />
with small spores (microspores). The megaspore wall<br />
is variously ornament<strong>ed</strong> according to species. The<br />
megaspores develop into female gametophytes, while<br />
the microspores produce male gametophytes.<br />
Stylites andicola Andes Quillwort<br />
This plant, forming cushions in marshes, was discover<strong>ed</strong><br />
in the Andes Mountains <strong>of</strong> Peru in 1957. The stem<br />
(p) branches dichotomously with the leaves (q) atop<br />
each section. The roots (r) develop on the sides <strong>of</strong> the<br />
stem.<br />
COLOR CODE<br />
dark green: leaves (b)<br />
green: spike (c), leaves (d, q), ligule (j)<br />
white: rhizophores (e), roots (h, r),<br />
megasporangium (m),<br />
microsporangium (o)<br />
tan: velum (l), stem (p)<br />
light green: spike (f), leaves (i)<br />
brown: corm (g)<br />
yellow: megaspore (n)
Horsetails<br />
The single genus, Equisetum, with 15 species, is the<br />
only present-day member <strong>of</strong> plants in this family, Equisetaceae.<br />
It is relat<strong>ed</strong> to the fossil plant, Calamites (see<br />
43). Species <strong>of</strong> Equisetum are found worldwide except<br />
in Australia and New Zealand.<br />
Characteristics. These annual or perennial terrestrial<br />
plants are less than 1 meter in height, with the exception<br />
<strong>of</strong> the Costa Rican tropical E. giganteum, which grows<br />
to 8 meters in height. The plant consists <strong>of</strong> a joint<strong>ed</strong> underground<br />
perennial rhizome and annual upright joint<strong>ed</strong><br />
shoots.<br />
Species with branch<strong>ed</strong> shoots are commonly call<strong>ed</strong><br />
“horsetails” and unbranch<strong>ed</strong> species are known as<br />
“scouring rushes” because <strong>of</strong> their earlier use as pot<br />
scrubbers (effective because <strong>of</strong> the presence <strong>of</strong> amorphous<br />
silica, SiO2·nH2O, in the stem surface).<br />
The photosynthetic stem is round and groov<strong>ed</strong> on the<br />
outside and hollow in the center. At the stem node is<br />
a sheath <strong>of</strong> greatly r<strong>ed</strong>uc<strong>ed</strong> leaves <strong>of</strong> various teethlike<br />
shapes, depending on the species. In branch<strong>ed</strong><br />
species, whorls <strong>of</strong> branches develop at the base <strong>of</strong><br />
the leaf sheath. Internodes <strong>of</strong> the rhizomes and aerial<br />
shoots elongate by means <strong>of</strong> basally localiz<strong>ed</strong> intercalary<br />
meristems (see 15).<br />
Reproduction. The plant has an alternation <strong>of</strong> a sporophyte<br />
generation with an either male or bisexual gametophyte<br />
generation as follows: The sporophyte produces<br />
a terminal “cone” (strobilus) with whorls <strong>of</strong><br />
hexagonal scales (sporophylls) on stalks. Attach<strong>ed</strong> to<br />
each scale are 5 to 10 spore-bearing sacs (sporangia)<br />
containing alike spores (homosporous). The spores<br />
contain chlorophyll. They germinate within a few days,<br />
developing into tiny green thalloid gametophytes that<br />
produce antheridia with sperm or both antheridia and<br />
archegonia. Fertilization <strong>of</strong> the egg in an archegonium<br />
66<br />
by a sperm results in a zygote that develops into a new<br />
sporophyte plant.<br />
Equisetum variegatum Variegat<strong>ed</strong> Scouring<br />
Rush<br />
Equisetum stems (a) are groov<strong>ed</strong> and possess hollow<br />
air channels within. The air channels include a central<br />
canal (b), carinal canals (c), and vallecular canals (d)<br />
at the bottom <strong>of</strong> each groove. Size and shape <strong>of</strong> the air<br />
canals vary with species.<br />
Equisetum arvense Field Horsetail<br />
This species has two forms (dimorphic). In the spring,<br />
an unbranch<strong>ed</strong> fertile shoot (e) emerges from the rhizome<br />
(f). It is short-liv<strong>ed</strong> and dies back when the spores<br />
are sh<strong>ed</strong> from the strobilus (g). The other form <strong>of</strong><br />
stem (h) is smooth and branch<strong>ed</strong> (i). By summer, the<br />
branches have elongat<strong>ed</strong>. The leaf sheaths (j) in this<br />
species have dark, lance-shap<strong>ed</strong> teeth (k).<br />
Equisetum laevigatum Smooth Scouring Rush<br />
The scouring rush stem (l) is unbranch<strong>ed</strong>. The leaf<br />
sheath (m) is flar<strong>ed</strong> and has deciduous teeth (n). The<br />
strobilus (o) shows the hexagonal surface <strong>of</strong> the sporophylls<br />
(p).<br />
Equisetum hyemale Common Scouring Rush<br />
A sporophyll remov<strong>ed</strong> from the stobilus exposes the<br />
sporangia (q) containing the spores.<br />
Equisetum scirpoides Dwarf Scouring Rush<br />
A spore (r) surface splits into 4 strips <strong>of</strong> water-absorbing<br />
(hydroscopic) elators (s). When dry, the elators (t) expand<br />
and aid in spore dispersal.<br />
COLOR CODE<br />
green: stem (a, h), branches (i), sheath (j),<br />
sporangium (q)<br />
colorless: canals (b, c, d)<br />
tan: shoot (e), strobilus (g)<br />
dark brown: rhizome (f)<br />
yellow-green: stem (l), sheath (m), surface <strong>of</strong><br />
sporophylls (p), spores (r), elators (s, t)
Ferns<br />
Characteristics. Although fern origins are uncertain,<br />
fossils have been found dating back to the Devonian.<br />
Most fern species have leafy fronds that unroll as the<br />
leaf expands (circinate development, see 69). Stems<br />
lack secondary growth, have roots that are usually<br />
creeping or below ground, and may have protective<br />
hairs or scales. The leaves may be simple, feather-like<br />
(pinnate), lob<strong>ed</strong>, with veins arising from one point (palmate),<br />
or with veins which appear to branch. Plant size<br />
ranges from a few millimeters to 15 meters.<br />
Ferns are perennials and may take the form <strong>of</strong> twining<br />
vines, floating plants, trees, epiphytes, or, most commonly,<br />
terrestrial herbs. While most species <strong>of</strong> ferns<br />
are found in the moist tropics, some grow in bare rocky<br />
habitats, or temperate swamps, fields and forests.<br />
Reproduction. Asexual reproduction occurs by <strong>of</strong>fshoots<br />
from a rhizome and by spores. The sporophyte<br />
generation is dominant and produces 1n spores<br />
in spore cases (sporangia), usually on the lower leaf<br />
surface. The spore cases are massive in the primitive<br />
orders, Ophioglossales (Adder’s-tongue Ferns) and<br />
Marattiales.<br />
In the more advanc<strong>ed</strong> orders, the spore cases are<br />
minute, nearly microscopic, stalk<strong>ed</strong>, and in a “fruit dot”<br />
cluster call<strong>ed</strong> a sorus. The sculptur<strong>ed</strong>, thick-wall<strong>ed</strong><br />
spores are dispers<strong>ed</strong> by wind and germinate into the<br />
sexual gametophyte generation. The tiny, rarely seen<br />
gametophyte produces sperm in antheridia and eggs<br />
in archegonia. For fertilization to take place, the sperm<br />
must swim in water to the archegonium, a vase-shap<strong>ed</strong><br />
structure with one egg. After fertilization, a 2n zygote is<br />
form<strong>ed</strong> and develops into a sporophyte on the gametophyte.<br />
The gametophyte then dries up and dies.<br />
Of interest . . . ornamentals: Adiantum p<strong>ed</strong>atum (maidenhair<br />
fern), Athyrium filix-femina (lady fern), A. nipponicum<br />
‘Pictum’ (Japanese paint<strong>ed</strong> fern), Asplenium<br />
nidus (bird’s-nest fern), Camptosorus (walking fern),<br />
67<br />
Cyrtomium (holly fern), Dryopteris erythosora (autumn<br />
fern), D. filix-mas (robust male fern), D. marginalis<br />
(marginal wood fern) Nephrolepis (Boston fern), Onoclea<br />
sensibilis (sensitive fern), Osmunda cinnamonea<br />
(cinnamon fern), O. regalis (royal fern), Platycerium<br />
(staghorn fern), Polystichum acrostichoides (Christmas<br />
fern), P. polyblepharum (tassel fern); poisonous:<br />
Pteridium (bracken fern); horticulture: Osmunda<br />
(dri<strong>ed</strong> roots us<strong>ed</strong> as m<strong>ed</strong>ium for growing orchids); fertilizer:<br />
Azolla (mosquito fern, see 70).<br />
Ophioglossales. Plants in this order are mostly small<br />
and succulent with the leaf divid<strong>ed</strong> into sterile and<br />
fertile, sporangial-bearing parts. There are four genera:<br />
Botrychium (grape ferns), Ophioglossum (adder’stongue<br />
ferns), Cheiroglossa, and Helminthostachys.<br />
Botrychium dissectum Dissect<strong>ed</strong> Grape Fern<br />
The single succulent compound leaf (a) is divid<strong>ed</strong> into<br />
pinnae (b), a primary subdivision <strong>of</strong> the leaf and pinnules<br />
(c), a further subdivision <strong>of</strong> the pinnae. The fertile<br />
stalk (d) is divid<strong>ed</strong> into many branches where sporangia<br />
(e) are borne in grape-like clusters. The roots (f) are<br />
coarse. This terrestrial fern is found on the forest floor<br />
<strong>of</strong> woods and in swamps.<br />
Helminthostachys zeylanica<br />
This fern is found in Southeast Asian and Polynesian<br />
swamps. The compound leaf is divid<strong>ed</strong> into 3 leaflets<br />
(h). The fertile spike (i) has very short branches bearing<br />
sporangia (j).<br />
Ophioglossum vulgatum Adder’s-tongue Fern<br />
The single stalk (k) has one simple blade (l) without a<br />
petiole (sessile), and sunken sporangia (m) borne terminally<br />
in a spike. The roots (n) are smooth and fleshy.<br />
Adder’s-tongue fern grows in damp areas in fields and<br />
woods in the temperate region.<br />
COLOR CODE<br />
green: leaf (a, b, c, h), stalk (d, g), spike (i)<br />
orange: sporangia (e, j)<br />
brown: roots (f)<br />
light green: stalk (k), leaf (l)<br />
yellow: sporangia (m)<br />
white: roots (n)
Common Ferns<br />
Common Ferns (Polypodiales). Most common ferns<br />
are in this order. They are usually <strong>of</strong> m<strong>ed</strong>ium size among<br />
the ferns and are found on most parts <strong>of</strong> the earth.<br />
Sporangia are single, or more <strong>of</strong>ten, there are many<br />
in a cluster call<strong>ed</strong> a sorus. In some genera, the sorus<br />
has a protective covering (indusium). Some ferns in<br />
this order produce sporangia on separate, fertile stalks,<br />
but most have the sporangia on the underside <strong>of</strong> the<br />
frond (leaf) in sori, or on the entire surface, or in rows<br />
along the veins, or under the curl<strong>ed</strong> <strong>ed</strong>ge <strong>of</strong> the leaflets.<br />
There are over 8,000 species.<br />
Osmunda regalis Royal Fern<br />
There are three species <strong>of</strong> Osmunda: O. cinnamomea<br />
(cinnamon fern), O. claytonia (interrupt<strong>ed</strong> fern), and<br />
O. regalis (royal fern). O. cinnamomea has two types <strong>of</strong><br />
stalks (dimorphic): a sterile frond (leaf) and a separate<br />
fertile stalk with cinnamon-color<strong>ed</strong> sporangia. It grows<br />
in shady, wet areas with acid soil. The fertile fronds <strong>of</strong><br />
O. claytonia have a fertile central area <strong>of</strong> sporangia<br />
on the stalk with pinnae above and below. It prefers<br />
a dry type <strong>of</strong> soil compar<strong>ed</strong> to the other two species <strong>of</strong><br />
Osmunda.<br />
Osmunda regalis is shown here. The fern leaf (a) is<br />
twice divid<strong>ed</strong> into pinnae (b) and bears sporangial<br />
branches (c) terminally. The round single spore cases<br />
(sporangia, d) open in halves and occur in clusters (e).<br />
The deciduous leaves arise from a perennial rhizome<br />
with black wiry roots. Royal fern grows in very wet habitats<br />
with acid soil.<br />
Dryopteris carthusiana (D. spinulosa)<br />
Tooth<strong>ed</strong> Wood Fern<br />
The usually evergreen leaf <strong>of</strong> this fern is three-times<br />
dissect<strong>ed</strong>, forming delicate pinnules (f) in the pinna<br />
(g). Scales (h) cover the petiole (i). Sori are produc<strong>ed</strong><br />
on the leaf underside. The sorus (j) is cover<strong>ed</strong> by a<br />
kidney-shap<strong>ed</strong> indusium (k) that protects the sporangia<br />
(l). The preferr<strong>ed</strong> habitat is moist shade to partial<br />
sun. There are about 150 species <strong>of</strong> Dryopteris (wood<br />
ferns).<br />
68<br />
COLOR CODE<br />
r<strong>ed</strong>-brown: petiole (a), sporangium (d, l),<br />
sporangial clusters (e)<br />
green: pinnae (b), pinnules (f)<br />
tan: scales (h), petiole (i), indusium (k)
Fern Leaf Development<br />
Common Ferns (continu<strong>ed</strong>)<br />
Rumohra adiantiformis Leatherleaf Fern<br />
Florists frequently use the sturdy fronds <strong>of</strong> this tropical<br />
fern. The young leaf meristem is protect<strong>ed</strong> by scales (a,<br />
b). As in other common ferns, the fiddlehead (crozier,<br />
c, d) expands by unrolling (circinate development).<br />
Ferns are the only plants with this type <strong>of</strong> leaf development.<br />
As the stalk (petiole) elongates, the blade midrib develops<br />
leaflets (pinnae, e). In this genus, the leaflets<br />
(pinnae) are further divid<strong>ed</strong> into smaller leaflet sections<br />
call<strong>ed</strong> pinnules (f, g).<br />
(This illustration was made from a series <strong>of</strong> drawings<br />
from one leaf as it develop<strong>ed</strong>.)<br />
69<br />
COLOR CODE<br />
brown: scales (a, b)<br />
green: crozier (c, d)<br />
dark green: leaf (e, f, g)
Water Ferns<br />
Water Ferns (Marsileales). Water ferns in this order<br />
usually have root<strong>ed</strong> rhizomes. The leaf may have 0, 2,<br />
or 4 leaflets on a long petiole. Spore-bearing receptacles<br />
(sporocarps) are form<strong>ed</strong> along the petiole. A<br />
sporocarp develops both small microspores and larger<br />
megaspores (a heterosporous condition) on one plant<br />
(monoecious).<br />
Marsilea quadrifolia Water Clover<br />
This pond plant is root<strong>ed</strong> (a) in mud with leaves floating<br />
on or near the water surface. The creeping rhizome (b)<br />
develops new leaves (c), which have 2 pairs <strong>of</strong> opposite<br />
leaflets (d).<br />
Salviniales (Floating Ferns). The floating ferns include<br />
Salvinia and Azolla. The plant consists <strong>of</strong> a<br />
branch<strong>ed</strong> stem and leaves. Sporocarps containing two<br />
types <strong>of</strong> spores (heterosporous) are borne on the<br />
leaves.<br />
Salvinia Water Spangles<br />
The leaves occur in whorls <strong>of</strong> 3 with two keel<strong>ed</strong>, green<br />
floating leaves (f) and a colorless, finely divid<strong>ed</strong>, submerg<strong>ed</strong><br />
leaf (g). The upper surface <strong>of</strong> the floating leaves<br />
is cover<strong>ed</strong> with rows <strong>of</strong> 4 rib-topp<strong>ed</strong>, transparent hairs<br />
(h). The hairs cause water droplets to maintain surface<br />
tension and roll <strong>of</strong>f the leaf surface.<br />
The submerg<strong>ed</strong> leaf filaments are cover<strong>ed</strong> with brown<br />
hairs, which function as roots for water and nutrient absorption.<br />
Sporocarps (i) are borne on submerg<strong>ed</strong> leaf<br />
filaments.<br />
Azolla Mosquito Fern<br />
This floating fern has simple roots (j) that hang down<br />
in the water. The leaves are alternate on the stem (k)<br />
and two-lob<strong>ed</strong>, having a green, fleshy lobe (l) above the<br />
water and a colorless flat lobe (m) on the water surface.<br />
Some Azolla species have a symbiotic relationship with<br />
a blue-green, Anabaena (see 44), which lives in cavities<br />
<strong>of</strong> the fern. Anabaena converts nitrogen from the air into<br />
a r<strong>ed</strong>uc<strong>ed</strong> form (ammonia - NH3) that can be us<strong>ed</strong> by the<br />
fern and surrounding water plants such as rice (Oryza<br />
sativa). Because the presence <strong>of</strong> Azolla with Anabaena<br />
increases rice production, this tiny plant is probably the<br />
economically most important fern.<br />
70<br />
COLOR CODE<br />
brown: roots (a), leaf hairs (g)<br />
white: rhizome (b), root (j), stem (k)<br />
green: leaf (c), leaflets (d), petioles (e)<br />
light green: leaf (f), leaf lobe (l)<br />
tan: sporocarps (i)
Cycads<br />
The fossil history <strong>of</strong> the cycads extends back 200 million<br />
years to the Mesozoic era. Cycads are now confin<strong>ed</strong><br />
to the tropics and subtropics as living relics <strong>of</strong> once<br />
worldwide distribution. They are the most primitive living<br />
se<strong>ed</strong> plants.<br />
Characteristics. Cycads look like sturdy ferns or palm<br />
trees. They have thick upright stems with a primary<br />
thickening meristem and not much secondary growth.<br />
The leaves are large, compound fronds with leaflets.<br />
Leaflets are thick and tough, usually with equally<br />
branching (dichotomous) veins.<br />
Typically, cycads reach a maximum height <strong>of</strong> 2 to 3 meters,<br />
but some species grow to 20 meters high. Cycad<br />
plants are slow-growing and long-liv<strong>ed</strong>, some as old as<br />
1,000 years.<br />
Reproduction. Unisexual cones (strobili) are borne<br />
on separate plants (dioecious). The male cone has<br />
spirally arrang<strong>ed</strong> cone scales (microsporophylls) with<br />
spore cases (sporangia) on the lower surface. The<br />
spore case contains microspores that develop into<br />
pollen grains that are dispers<strong>ed</strong> to the female reproductive<br />
cones. There, the pollen grain develops mutiflagellat<strong>ed</strong><br />
sperm. The cycads and Ginkgo are the only<br />
living se<strong>ed</strong> plants having flagellat<strong>ed</strong> sperm.<br />
The female cone scales (megasporophylls) produce<br />
ovules in which eggs develop. After fertilization,<br />
71<br />
brightly-color<strong>ed</strong>, usually r<strong>ed</strong>, se<strong>ed</strong>s are form<strong>ed</strong>. Cycads,<br />
Ginkgo, conifers and gnetes are referr<strong>ed</strong> to as<br />
gymnosperms, meaning “nak<strong>ed</strong> se<strong>ed</strong>, “ because the<br />
se<strong>ed</strong>s are borne in an expos<strong>ed</strong> position on the sporophyll.<br />
Of interest . . . houseplants or landscape plants for<br />
tropical areas include Bowenia serrulata, B. spectabilis,<br />
Ceatozamia latifolia, C. robusta, Cycas circinalis (fern<br />
palm), C. revoluta (sago palm), Dioön <strong>ed</strong>ule, Encephalartos,<br />
and Zamia.<br />
Zamia furfurscea<br />
Leaflets (a) have dichotomous venation but do not have<br />
midribs. They leave prominent leaflet scars (b) when<br />
they are sh<strong>ed</strong> (abscise). The male cone (d) has stalk<strong>ed</strong><br />
cone scales (e) with clusters <strong>of</strong> spore cases (f) on the<br />
under surfaces. The female cone scale (g) has a hexagonal<br />
surface (h), and below, are 2 ovules (j) in which the<br />
eggs develop.<br />
Dioön <strong>ed</strong>ule<br />
The habit illustration <strong>of</strong> this cycad shows the prominent<br />
stem (l) cover<strong>ed</strong> with old leaf bases (m). A spiral pattern<br />
<strong>of</strong> leaves (n) emerges at the apex. Leaflets (o) are<br />
arrang<strong>ed</strong> in two rows.<br />
COLOR CODE<br />
green: leaflets (a, o)<br />
tan: leaf stalk (c), spore case (f), cone stalk<br />
(k), cone scale stalk (i)<br />
brown: cone (d), cone scale stalk, surface (e)<br />
dark green: cone scale (g, h)<br />
white: ovules (j)<br />
r<strong>ed</strong>-brown: stem, leaf (l, m)
Ginkgo<br />
This division has only one living member: Ginkgo biloba<br />
(Maidenhair Tree). Fossil records show it probably originat<strong>ed</strong><br />
in the Permian about 250 million years ago.<br />
Members <strong>of</strong> the division were globally distribut<strong>ed</strong>, but<br />
became extinct except for this single species in southeastern<br />
China. Ginkgo is similar to cycads in reproductive<br />
structures and gametophyte development, but the<br />
leaves are distinctively different. The stem, with extensive<br />
wood, small pith and cortex, and cell wall pitting, is<br />
similar to that <strong>of</strong> the conifers (see 15).<br />
Ginkgo biloba Maidenhair Tree<br />
This plant was cultivat<strong>ed</strong> in temple and monastery gardens<br />
<strong>of</strong> China and Japan for centuries. The Chinese<br />
name was mistransliterat<strong>ed</strong> and should be Ginkyo. The<br />
common name is deriv<strong>ed</strong> from a resemblance <strong>of</strong> the<br />
leaves to the leaflets <strong>of</strong> the maidenhair fern (Adiantum<br />
p<strong>ed</strong>atum).<br />
Characteristics. A hardy tree with a slow maturation<br />
rate, Ginkgo can grow to 30 to 40 meters (60 to 80<br />
feet) in height and over 1 meter (3.3 feet) in diameter. It<br />
can live to 1,000 years. After the first 10 to 20 years <strong>of</strong><br />
vertical growth, laterally spreading branches develop.<br />
The leaf blades (a) are fan-shap<strong>ed</strong>, lob<strong>ed</strong>, and have<br />
dichotomous venation (each vein branches into two<br />
smaller veins). The alternate leaves are mainly twolob<strong>ed</strong><br />
(biloba, b) on long shoots (c) and wavy-margin<strong>ed</strong><br />
on short spur shoots (d) where they appear in a whorl<strong>ed</strong><br />
72<br />
arrangement. In autumn, the deciduous leaves fade to<br />
yellow (chlorophylls disappear) and all are sh<strong>ed</strong> from a<br />
tree within a few hours, especially after a hard frost.<br />
Reproduction. Unisexual structures are borne on separate<br />
trees (dioecious). The male structures are catkinlike<br />
strobili (e) <strong>of</strong> spore cases that develop in leaf axils.<br />
Two male spore cases (f) develop on a stalk (g). The<br />
female strobilus has two terminal, “nak<strong>ed</strong>” ovules (h)<br />
on a stalk (i) and thus, Ginkgo is referr<strong>ed</strong> to as a gymnosperm<br />
(= nak<strong>ed</strong> se<strong>ed</strong>).<br />
In the spring, wind carries pollen to an opening (micropyle)<br />
in the ovule. The se<strong>ed</strong> (j) has a fleshy outer<br />
layer with the odor <strong>of</strong> rancid butter when mature.<br />
An embryo with two primary leaves (cotyl<strong>ed</strong>ons) develops<br />
after the se<strong>ed</strong> has been sh<strong>ed</strong>.<br />
Of interest...this “living fossil” may be the oldest surviving<br />
se<strong>ed</strong> plant. It is cultivat<strong>ed</strong> as an ornamental shade<br />
tree because <strong>of</strong> its resistance to pathogens and pollutants,<br />
and its drought and low-temperature tolerance.<br />
The tree ne<strong>ed</strong>s sun, but grows in almost any soil.<br />
Because <strong>of</strong> the odoriferous se<strong>ed</strong>s from female trees,<br />
male trees are preferr<strong>ed</strong>. There are various cultivars select<strong>ed</strong><br />
for particular shapes. ‘Autumn Gold’ is a broadshap<strong>ed</strong><br />
cultivar. The ‘Fairmount’ cultivars are coneshap<strong>ed</strong>.<br />
‘Sentry’ (Ginkgo biloba cv. fastigata) cultivars<br />
are narrow, column shap<strong>ed</strong>.<br />
COLOR CODE<br />
yellow: long shoot leaf (b), male strobili (e),<br />
spore cases (f)<br />
green: leaves (a), stalks (g, i)<br />
tan: long shoot (c)<br />
brown: spur shoots (d)<br />
light green: ovules (h)<br />
yellow-orange: se<strong>ed</strong> (j)
Conifers<br />
Conifers have been present on the earth since the Carboniferous.<br />
Present-day conifers have fossil records<br />
dating back to the Jurassic time <strong>of</strong> the Mesozoic.<br />
Conifers, as well as cycads, Ginkgo and gnetes, are referr<strong>ed</strong><br />
to as gymnosperms (gymno = nak<strong>ed</strong>, sperm =<br />
se<strong>ed</strong>) because <strong>of</strong> their nak<strong>ed</strong> se<strong>ed</strong>s. There are 550<br />
species <strong>of</strong> 50 genera <strong>of</strong> conifers.<br />
Characteristics. Almost all conifers are woody trees,<br />
having one central trunk from which branches extend.<br />
Most have narrow, evergreen leaves commonly call<strong>ed</strong><br />
ne<strong>ed</strong>les (see 21, 22). Leaves are borne singly or in<br />
fascicles. They may be arrang<strong>ed</strong> in a spiral, opposite,<br />
or whorl<strong>ed</strong> manner, or occur on short spur shoots. Larix<br />
(larch) and Taxodium (bald cypress) have deciduous<br />
leaves that are sh<strong>ed</strong> in autumn.<br />
Conifers prefer cooler climates forming climax forests<br />
at high altitudes, as well as in the temperate regions.<br />
Conifers are the tallest known trees, with giant<br />
sequoia (Sequoiadendron giganteum) and r<strong>ed</strong>wood<br />
(Sequoia sempervirens), which may reach 115 meters<br />
and live thousands <strong>of</strong> years. There are seven families:<br />
pine family (Pinaceae), araucaria family (Araucariaceae),<br />
sequoia family (Taxodiaceae), cypress family<br />
(Cupressaceae), podocarpus family (Podocarpaceae),<br />
plum-yew family (Cephalotaxaceae) and yew family<br />
(Taxaceae).<br />
Reproduction. Conifers bear pollen sacs and ovules<br />
in separate structures (stobili = cones) on the same<br />
plant (monoecious). Wind currents carry pollen to female<br />
strobili, where the nak<strong>ed</strong> se<strong>ed</strong>s are borne. Or the<br />
strobilus may be an open fleshy aril that surrounds a<br />
single se<strong>ed</strong>, as in Taxus (yew).<br />
Of interest . . . timber and paper pulp: Abies (fir),<br />
Chamaecyparis spp. (false-cypress), Picea spp.<br />
(spruces), Pinus spp. (pines), Pseudotsuga menziesii<br />
(Douglas fir), Sequoia (r<strong>ed</strong>wood), Taxodium (bald<br />
cypress); naval stores (turpentine, wood oil, wood<br />
tars, rosin): Picea spp. (spruces), Pinus (pines); food:<br />
Juniperus (juniper “berry” flavoring), Pinus spp. (se<strong>ed</strong>s<br />
<strong>of</strong> pinyon pines); ornamentals: Abies (fir), Araucaria<br />
araucana/A. imbricata (monkey puzzle tree), A.<br />
excelsa (Norfolk Island pine), Cupressus (cypress),<br />
Juniperus spp. (juniper, r<strong>ed</strong> c<strong>ed</strong>ar), Larix decidua<br />
(European larch), L. laricina (tamarack, eastern larch),<br />
L. occidentalis (western larch), Picea spp. (spruces),<br />
Taxus (yew), Thuga (arborvitae, white c<strong>ed</strong>ar), Tsuga<br />
73<br />
spp. (hemlocks); poisonous: Taxus (yew: wood, bark,<br />
leaves, se<strong>ed</strong>s); m<strong>ed</strong>icinal: Taxus brevifolia (Pacific<br />
yew) bark contains taxol, us<strong>ed</strong> to treat breast and ovarian<br />
cancers; Abies balsamina (balsam fir), pitch from<br />
blister/bubbles on trunks was us<strong>ed</strong> to treat burns by<br />
Ojibwa Indians. It prevents infections, hastens healing,<br />
and kills the pain; tallest tree on earth: Sequoia sempervirens<br />
can be up to 25 feet (7.6 meters) in diameter<br />
and up to 350–375 feet (106.2–113.75 meters) high.<br />
It is only found in Northern California where 96% <strong>of</strong><br />
virgin r<strong>ed</strong>wood forests have been cut down.<br />
Picea glauca White Spruce<br />
As a member <strong>of</strong> the pine family (Pinaceae), this tree<br />
has ne<strong>ed</strong>le-like, evergreen leaves (a). The male cone<br />
is compos<strong>ed</strong> <strong>of</strong> spirally arrang<strong>ed</strong> cone scales (b) with<br />
pollen sacs on the sides. In the spring, after clouds <strong>of</strong><br />
yellow pollen (c) are dispers<strong>ed</strong>, the cone disintegrates.<br />
The young female cone has woody, spirally arrang<strong>ed</strong><br />
cone scales (d) with outer bracts (e). On the inner surface<br />
<strong>of</strong> each scale, two ovules (f), that after fertilization,<br />
become embryos that develop into se<strong>ed</strong>s. At maturity,<br />
the cone (g) opens and wing<strong>ed</strong> se<strong>ed</strong>s (h) are releas<strong>ed</strong>.<br />
Taxus Yew<br />
This yew family (Taxaceae) shrub has flat, evergreen<br />
leaves (i) and bears male and female structures on separate<br />
plants (dioecious). The female reproductive structure<br />
has scales (j) at the base, and a band <strong>of</strong> tissue (k)<br />
that matures into a fleshy aril (l) that envelops the se<strong>ed</strong><br />
(m). The r<strong>ed</strong> aril attracts and is eaten by birds that discard<br />
the poisonous se<strong>ed</strong>.<br />
COLOR CODE<br />
green: leaves (a, i)<br />
r<strong>ed</strong>: cone scales (b), aril (l)<br />
yellow: pollen (c), scales (j)<br />
tan: cone scale (d), bract (e), ovule (f),<br />
se<strong>ed</strong> (h)<br />
brown: cone (g)<br />
light green: tissue (k)<br />
brown-green: se<strong>ed</strong> (m)
Gnetes<br />
There are three genera in this division: Eph<strong>ed</strong>ra, Welwitschia,<br />
and Gnetum. Pollen grains <strong>of</strong> Eph<strong>ed</strong>ra have<br />
been found from the Permian. Even though origins and<br />
relationships <strong>of</strong> these plants with others are not known,<br />
they are term<strong>ed</strong> gymnosperms because they bear expos<strong>ed</strong><br />
ovules. Most Gnetes are dioecious (two households)<br />
with male and female cones on separate plants.<br />
Eph<strong>ed</strong>ra<br />
These plants grow in warm, dry temperate areas. They<br />
are perennial shrubs. Oppositely branching stems (a)<br />
bear whorls <strong>of</strong> scale-like evergreen leaves (b) and male<br />
structures (strobili, c) at the nodes. Sporangia (d)<br />
are protect<strong>ed</strong> by bracts (e) and bracteoles (f). Stalk<strong>ed</strong><br />
female structures (strobili, g) are borne at nodes and<br />
protect<strong>ed</strong> by bracts (h). Two se<strong>ed</strong>s (i) develop after<br />
fertilization.<br />
An alkaloid, eph<strong>ed</strong>rine, occurs in these plants. In ancient<br />
China, eph<strong>ed</strong>rine was us<strong>ed</strong> to relieve hay fever<br />
and asthma symptoms. Its action stimulates the heart<br />
and nervous system, by constricting blood vessels and<br />
expanding bronchial tubes. This raises blood pressure<br />
and can cause heart attack, tachycardia, palpitation,<br />
psychosis and death.<br />
74<br />
Welwitschia mirabilis<br />
This unusual plant, discover<strong>ed</strong> in 1859 by Fri<strong>ed</strong>rich<br />
Welwitsch, is native to a small area on the dry, southwest<br />
coast <strong>of</strong> Africa. Plants may live for over 2,000<br />
years. Its woody stem (j) protrudes slightly out <strong>of</strong> the<br />
sandy soil and has only 2 strap-shap<strong>ed</strong> leaves (k) produc<strong>ed</strong><br />
from long-liv<strong>ed</strong> intercalary meristems (l).<br />
Unisexual cones, borne on stalks that arise from the<br />
apical meristemic region (see 15), are produc<strong>ed</strong> on separate<br />
plants (dioecious). The male cone is compos<strong>ed</strong><br />
<strong>of</strong> bracts (cone scales) with bracteoles (m) covering<br />
a smaller strobilus on each bract. With the bracteoles<br />
remov<strong>ed</strong>, six spore cases (sporangia, n), with three<br />
lobes each, may be seen. They surround a central,<br />
sterile ovule (o). Pollen is form<strong>ed</strong> in the sporangia. The<br />
four-sid<strong>ed</strong> female cone has overlapping scales (p). An<br />
integument (q), consisting <strong>of</strong> an outer layer <strong>of</strong> cells that<br />
covers the ovule, protrudes from each scale.<br />
Gnetum<br />
A plant <strong>of</strong> the tropics, most species are vines (lianas)<br />
with a few shrubs and trees. Opposite leaves (r) resemble<br />
those <strong>of</strong> dicot flowering plants. Unisexual strobili are<br />
produc<strong>ed</strong> on separate plants (dioecious).<br />
COLOR CODE<br />
green: stems (a), leaves (b, r), stobilus (c, g),<br />
bracts (e, h), bracteoles (f)<br />
yellow: sporangia (d,)<br />
tan: se<strong>ed</strong>s (i), stem (j), bracteoles (m),<br />
ovule (o), scales (p)<br />
light green: apical meristem (l)<br />
gray-green: leaves (k)
Flowering Plant Classification<br />
The dominant plants <strong>of</strong> the earth today are the flowering<br />
plants. While their fossil record dates from the<br />
Cretaceous when they diversifi<strong>ed</strong> rapidly, their ancestral<br />
origin is not known (see 41). Sizes range from a<br />
one-millimeter duckwe<strong>ed</strong> (Wolffia) to the 100-meter tall<br />
Australian gum tree (Eucalpytus).<br />
Flowering plants are call<strong>ed</strong> angiosperms (angio = cover<strong>ed</strong>,<br />
sperm = se<strong>ed</strong>), plants that have se<strong>ed</strong>s enclos<strong>ed</strong><br />
in a fruit that develops from an ovary. There are two<br />
classes: Magnoliopsida, the dicots (embryos with two<br />
se<strong>ed</strong> leaves—dicotyl<strong>ed</strong>ons), and Liliopsida, the monocots<br />
(embryos with one se<strong>ed</strong> leaf - monocotyl<strong>ed</strong>ons).<br />
There are 354 families in the two classes. Flower characteristics<br />
and differences in chloroplast DNA separate<br />
subclasses and families.<br />
Dicot (Magnoiliopsida) Subclasses<br />
Magnoliidae (36 families). These flowering plants are<br />
among the most primitive. Their flowers usually have an<br />
indefinite number <strong>of</strong> parts with many petals, many stamens,<br />
and many separate carpels. Pollen grains have<br />
one pore (call<strong>ed</strong> unicolpate condition, see 31).<br />
Hamamelidae (23 families). The flowers are small,<br />
usually unisexual, and are adapt<strong>ed</strong> towards wind<br />
pollination.<br />
Caryophyllidae (14 families). This group alone has<br />
the water-soluble betalain pigments (see 4) <strong>of</strong> betacyanins<br />
(beet r<strong>ed</strong>-purple) and betaxanthins (yellow, orange,<br />
orange-r<strong>ed</strong>). The flower ovary usually has freecentral<br />
to basal placentation (see 28) and the ovule integuments<br />
are twist<strong>ed</strong> and bent.<br />
Dilleniidae (69 families). The flower has many stamens,<br />
which mature in a sequence from inside to the<br />
outside. Parietal placentation <strong>of</strong> the ovules is common.<br />
Rosidae (108 families). Structurally, this group has no<br />
one common feature, but developmentally, the plants<br />
are plac<strong>ed</strong> between the primitive Magnoliidae and the<br />
advanc<strong>ed</strong> Asteridae.<br />
Asteridae (43 families). In 70% <strong>of</strong> these plants, the<br />
flower petals are fus<strong>ed</strong>, at least at the base, and the<br />
stamens arise form the petals.<br />
Monocot (Liliopsida) Subclasses<br />
Alismatidae (14 families). These primitive monocots<br />
are mostly aquatic plants. The flower carpels are<br />
75<br />
usually separate and the pollen grains possess three<br />
pores (tricolpate condition, see 31).<br />
Commelinidae (16 families). Plants in this subclass<br />
are mostly terrestrial. The flower carpels are usually<br />
join<strong>ed</strong> and the se<strong>ed</strong> usually has a starchy endosperm<br />
(see 40). The sepals and petals are separate or r<strong>ed</strong>uc<strong>ed</strong><br />
to bristles or absent.<br />
Zingiberidae (9 families). This subclass is separat<strong>ed</strong><br />
from Commelinidae by the presence <strong>of</strong> septal nectaries,<br />
and vessels (see 8) are found only in the roots.<br />
Arecidae (5 families). The flower are usually small<br />
and numerous in a cluster, subtend<strong>ed</strong> by a bract<br />
(spathe), and <strong>of</strong>ten aggregat<strong>ed</strong> into a fleshy spike<br />
(spadix).<br />
Liliidae (17 families). Tepals (sepals and petals that<br />
look alike) and well-develop<strong>ed</strong> nectaries are usually<br />
present in the flower. This subclass includes the most<br />
specializ<strong>ed</strong> monocot flowers.<br />
Evolutionary Floral Trends<br />
Evolutionary changes from primitive to more advanc<strong>ed</strong><br />
forms may include the following. R<strong>ed</strong>uction, where<br />
flower structures are less in size, number, and kinds<br />
<strong>of</strong> parts. Petals are most frequently lost; stamens or<br />
carpels may be lost (bisexual to unisexual flower, see<br />
28), with, usually, sepals the last to be lost because<br />
they protect the young flower. There may be fusion <strong>of</strong><br />
parts, such as petals forming a tube instead <strong>of</strong> being<br />
separate. Instead <strong>of</strong> a superior position, the ovary is in<br />
an inferior position (see 28). The lower, less-expos<strong>ed</strong><br />
position provides more protection <strong>of</strong> the ovules. The<br />
shift from insect to wind pollination is regard<strong>ed</strong> as an<br />
advanc<strong>ed</strong> evolutionary change. A change from radial to<br />
bilateral symmetry is an adaptation for specific insect<br />
pollinators. In radial (actinomorphic) symmetry, similar<br />
parts are regularly arrang<strong>ed</strong> around a central axis.<br />
With bilateral (zygomorphic symmetry), flowers can be<br />
divid<strong>ed</strong> into equal halves in one plane only. Some advanc<strong>ed</strong><br />
flowers are irregular (asymmetrical), incapable<br />
<strong>of</strong> being divid<strong>ed</strong> into equal halves in any plane. False<br />
flowers (pseudanthia) are compos<strong>ed</strong> <strong>of</strong> a head (capitulum)<br />
<strong>of</strong> small flowers that look like one flower. In the<br />
center <strong>of</strong> the head are fertile flowers surround<strong>ed</strong> on the<br />
outside by petaloid structures or large-petall<strong>ed</strong> sterile<br />
flowers.
COLOR CODE<br />
green: bract (a, h, r), leaf (e), female catkin (g),<br />
sepals (i, k, o)<br />
white: perianth (b), spadix <strong>of</strong> flowers (u),<br />
male-female column (w)<br />
yellow: stamens (c, m, q)<br />
light green: pistils (d, n), ovary (t)<br />
pink: petals (p, y), sepals (x)<br />
tan: male catkin (f)<br />
r<strong>ed</strong>: petals (j), bract (v)<br />
purple: petals (I)<br />
orange: petal (s)<br />
dark pink: lip petal (z)
Major Land Plant Communities<br />
Biomes are characteriz<strong>ed</strong> by their natural vegetation <strong>of</strong><br />
dominant plants determin<strong>ed</strong> by climate and position <strong>of</strong><br />
the continents. In earth’s history, biomes chang<strong>ed</strong> as<br />
the climate cycles cool<strong>ed</strong> or warm<strong>ed</strong> and continents<br />
drift<strong>ed</strong>.<br />
Arctic Tundra (a). This biome is wet, arctic grassland<br />
that supports lichens, grasses, s<strong>ed</strong>ges, and dwarf<br />
woody plants and is cold most <strong>of</strong> the year. Below<br />
a few centimeters, the soil is permanently frozen<br />
(permafrost).<br />
Northern Conifer Forests (b). Other names are boreal<br />
forest, spruce-fir forest and taiga. Low temperatures<br />
prevail for at least half the year. The plants include<br />
spruces, firs, and pines.<br />
Temperate Deciduous and Rain Forests (c). In the<br />
Temperate Zone, deciduous plants have an even distribution<br />
<strong>of</strong> 30 to 60 in. (76 to 152 cm) <strong>of</strong> rainfall annually<br />
and moderate seasonal temperatures. R<strong>ed</strong>woods,<br />
Douglas fir, western hemlock and western r<strong>ed</strong> c<strong>ed</strong>ar<br />
(see 73) dominate temperate rain forests along the<br />
West Coast <strong>of</strong> the Unit<strong>ed</strong> States. Rain forests <strong>of</strong> the<br />
subtropics with high moisture and even temperatures<br />
have broad-leav<strong>ed</strong> evergreens.<br />
Temperate Grassland (d). These areas have a low<br />
annual rainfall <strong>of</strong> 10 to 30 in. (25 to 76 cm) which effectively<br />
prevents forest formation. Temperatures range<br />
from very cold winters to very hot summers.<br />
Tropical Savanna (e). Warm regions with 40 to 60 in.<br />
(102 to 152 cm) <strong>of</strong> rainfall and with a prolong<strong>ed</strong> dry<br />
season have drought- and fire-resistant grasses with<br />
scatter<strong>ed</strong> trees.<br />
Desert (f). With less than 10 in. (25 cm) <strong>of</strong> annual rainfall<br />
in desert regions, plants include rain-season annuals,<br />
succulents, and shrubs which can remain dormant<br />
for long periods. Plants have light-reflecting surfaces<br />
creat<strong>ed</strong> by white hairs or waxy cuticle. Small stomata<br />
(see 10) are sunken or clos<strong>ed</strong> much <strong>of</strong> the time, opening<br />
at night. They also have extensive root systems.<br />
Chaparral (g). A mild climate with abundant winter<br />
rains and dry summers supports a community <strong>of</strong> trees<br />
or shrubs with thick evergreen leaves. Fire is an important<br />
maintenance factor. Native plants are fire-adapt<strong>ed</strong>.<br />
76<br />
Tropical Rain Forest (h). Equatorial lowlands have 80<br />
to 90 in. (203 to 230 cm) <strong>of</strong> annual rainfall. Broadleav<strong>ed</strong><br />
angiosperms with evergreen leaves include<br />
trees, vines, and epiphytes. Without freezing temperatures,<br />
there are no deciduous-leaf<strong>ed</strong> plants. Photosynthesis<br />
is continuous throughout the year.<br />
Tropical Scrub (i) and Deciduous (j) Forests. These<br />
are areas without an even distribution <strong>of</strong> rainfall. They<br />
are compos<strong>ed</strong> <strong>of</strong> thorn forests <strong>of</strong> distort<strong>ed</strong>, small hardwood<br />
trees.<br />
Mountains (k). Many irregular bands <strong>of</strong> different types<br />
<strong>of</strong> plant communities are present. Alpine tundra is<br />
above the treeline (too high for trees to survive). It<br />
occurs in mountainous areas much south <strong>of</strong> the arctic<br />
tundra. Coniferous forest in temperate zones, such<br />
as the Appalachian Mountain region in Eastern Unit<strong>ed</strong><br />
States, has dominant spruces, pines, firs and tamarack.<br />
Highland rain forests in the tropics can support trees.<br />
Of interest...Forests <strong>of</strong> the earth absorb carbon dioxide<br />
and release oxygen during photosynthesis (see 24).<br />
As forests are cut down and burn<strong>ed</strong>, potential oxygen is<br />
lost and carbon dioxide stor<strong>ed</strong> in the trees is releas<strong>ed</strong><br />
into the atmosphere. The rise <strong>of</strong> atmospheric carbon<br />
dioxide causes a rise in temperature. Along with gasemitting<br />
power plants, automobiles and factories, the<br />
temperature rose 1 ◦ Fahrenheit during the last century.<br />
As temperatures continue to rise, land habitats disappear.<br />
Satellite imaging can monitor deforestation. Brazil<br />
and Central Africa have the largest tropical rain forests,<br />
although deforestation by logging and mining is destroying<br />
this biome. From 1978 to 1996 burning (“slash and<br />
burn”) and logging to create pastures for livestock and<br />
fields for agriculture destroy<strong>ed</strong> 12.5% <strong>of</strong> the Amazon’s<br />
rain forest. Destruction continues unabat<strong>ed</strong>.<br />
COLOR CODE<br />
tan: tundra (a)<br />
dark green: northern conifer forest (b)<br />
r<strong>ed</strong>: temperate deciduous and rain forest (c)<br />
yellow: grassland (d)<br />
light green: tropical savanna (e)<br />
orange: desert (f)<br />
pink: chaparral (g)<br />
purple: tropical rain forest (h)<br />
brown: tropical scrub forest (i)<br />
gray: tropical deciduous forest (j)<br />
blue: mountains (k)
Magnolia Family (Magnoliaceae)<br />
This family <strong>of</strong> plants is consider<strong>ed</strong> to be among the most<br />
primitive <strong>of</strong> the flowering plants. It consists <strong>of</strong> woody<br />
shrubs and trees that may have deciduous or evergreen<br />
leaves. The flower parts (sepals, petals, stamens, pistils)<br />
are spirally arrang<strong>ed</strong> and usually without a definite<br />
number. These are consider<strong>ed</strong> to be primitive characteristics.<br />
There are 12 genera and over 200 species.<br />
The alternate leaves are simple and usually have<br />
smooth (entire) margins. They are pinnately (featherlike)<br />
vein<strong>ed</strong>. Petioles are present. Stipules (see 23) enclose<br />
young leaf buds and are sh<strong>ed</strong> as the leaves expand.<br />
Bracts that enclose flower buds are sh<strong>ed</strong> as the<br />
flower opens. Flowers are <strong>of</strong>ten large, showy, and solitary.<br />
These features attract pollinators, usually primitive<br />
insects, such as beetles.<br />
Flowers are usually bisexual, having both male and female<br />
structures. Sepals and petals look alike or there<br />
may be 3 sepals and 6 to many petals. Many stamens<br />
are spirally arrang<strong>ed</strong> around a rais<strong>ed</strong> axis with<br />
many pistils. Again, these are consider<strong>ed</strong> to be primitive<br />
characteristics.<br />
Each pistil has an ovary <strong>of</strong> one carpel containing one<br />
to many ovules in parietal placentation (see 28) and<br />
one style and stigma. Fruit types in this family include<br />
follicles (as in Magnolia), samaras (as in Liriodendron)<br />
and berries.<br />
Of interest...lumber: Liriodendron tulipifera (tulip<br />
tree, yellow poplar); cabinet work: Magnolia spp.<br />
77<br />
(magnolias); ornamentals: Liriodendron tulipifera<br />
(tulip tree), Magnolia acuminata (cucumber tree), M.<br />
denudata (Yulan magnolia), M. grandiflora (bull-bay),<br />
M. stellata (star magnolia), M. tripetala (umbrella tree),<br />
M. virginiana (sweet-bay), M. × soulangeana (saucer<br />
magnolia, a hybrid between M. denudata and M. liliflora,<br />
has large, deep pink, sterile flowers), Michelia fuscata<br />
(banana shrub), Talauma, Illicium vernum (Chinese<br />
anise, star anise).<br />
Magnolia spp. Magnolia<br />
The illustrations represent three showy ornamental<br />
Magnolia species: M. xsoulangeana (saucer magnolia),<br />
M. stellata (star magnolia), and M. grandiflora (bullbay,<br />
southern magnolia).<br />
In the spring, magnolia flowers open before the leaves<br />
(a) expand. Bud coverings <strong>of</strong> leaf stipules (b) and flower<br />
bracts (c) are fuzzy with hairs (pubescence).<br />
The star magnolia flower has many similar appearing<br />
sepals and petals (e) and many stamens (f) with anthers<br />
(g) that open longitudinally on both sides. Pistils<br />
(h) are arrang<strong>ed</strong> spirally on a central axis and occur in<br />
a position superior to other flower parts. Each pistil has<br />
a style (i) extending from the ovary (j).<br />
In fruit, the pistils form a cone-like aggregate <strong>of</strong> follicles.<br />
A follicle (k) splits along one seam. Inside each are one<br />
or two, bright r<strong>ed</strong>, flesh-cover<strong>ed</strong> se<strong>ed</strong>s (l) attach<strong>ed</strong> by<br />
thin strands (call<strong>ed</strong> funiculi, m) to the ovary wall (n).<br />
COLOR CODE<br />
green: leaf (a), pistils (h)<br />
gray-green: leaf bud stipules (b), flower bracts (c)<br />
brown: stem (d)<br />
white: sepals and petals (e)<br />
light yellow: stamens (f), anthers (g)<br />
pale green: style (i), ovary (j)<br />
pink-brown: outer follicle surface (k)<br />
r<strong>ed</strong>: se<strong>ed</strong> (l)<br />
tan: ovary wall (n)
Laurel Family (Lauraceae)<br />
Aromatic bark and leaves, and small flowers, with parts<br />
in whorls <strong>of</strong> three are characteristics <strong>of</strong> this family. A<br />
distinguishing feature <strong>of</strong> the family is the valvate anther<br />
dehiscence (see below in Sassafras). Plants are<br />
mostly evergreen, except in the Temperate Zone where<br />
they are deciduous. Forms are trees, shrubs, or vines.<br />
Usually, the leaves are alternate and have entire margins.<br />
There are about 32 genera with 2,500 species with<br />
most occurring in the tropics and subtropics <strong>of</strong> Southeast<br />
Asia and Brazil.<br />
The flowers are usually bisexual and develop as clusters<br />
in the leaf axils. A single flower has 6 sepal-petal<br />
parts and 12 stamens in 3 whorls. But one or two<br />
stamen whorls may be sterile “honey leaves” call<strong>ed</strong><br />
staminodes.<br />
The single pistil usually has an ovary above the other<br />
flower parts (a superior position), containing one ovule<br />
in parietal placentation, one style and one stigma. For<br />
fruit types, there are drupes or berries, which are enclos<strong>ed</strong><br />
at the base by the persistent sepal tube.<br />
Of interest...aromatic oils: Cinnamomum camphorum<br />
(camphor), C. zeylanicum (cinnamon bark spice),<br />
Lindera Benzoin (spice bush), Laurus nobilus (bay<br />
laurel, bay tree, sweet bay), Persea spp. (avocado),<br />
Sassafras albidum (sassafras); ornamentals:<br />
Laurus, Lindera benzoin (spicebush), Umbellularia<br />
californica (California laurel); food: Persea americana<br />
(avocado); lumber: Beilschmi<strong>ed</strong>ia, Endiandra (walnut<br />
bean, oriental walnut), Litsea (pond spice), Ocotea<br />
rodioei (greenheart, was us<strong>ed</strong> to make the original<br />
gates <strong>of</strong> the Panama Canal locks), O. bullata (South<br />
African stinkwood).<br />
78<br />
Sassafras albidum Sassafras<br />
Before the deciduous leaves are sh<strong>ed</strong>, this tree is easily<br />
recogniz<strong>ed</strong> by the shape <strong>of</strong> the alternate leaves (a).<br />
They are entire to five-lob<strong>ed</strong>, and all types may be<br />
present on one plant. In autumn, the leaves turn yellow.<br />
The bark is thick, aromatic, and dark r<strong>ed</strong>dish brown.<br />
Bark <strong>of</strong> the roots was distill<strong>ed</strong> for oil <strong>of</strong> sassafras, once<br />
us<strong>ed</strong> to flavor candy, root beer, and soap. Sassafras tea<br />
was popular, but now is regard<strong>ed</strong> as possibly carcinogenic.<br />
Usually seen as a small tree along forest <strong>ed</strong>ges,<br />
it may reach a height <strong>of</strong> 30 meters.<br />
Unlike most members <strong>of</strong> the laurel family, sassafras has<br />
only male flower clusters or only female flower clusters<br />
on a plant. This is a dioecious condition (<strong>of</strong> two households).<br />
The male flower has 6 sepals (b) and 3 whorls<br />
<strong>of</strong> stamens; an outer whorl <strong>of</strong> 6 functional stamens (c),<br />
an inner whorl <strong>of</strong> 6 stalk<strong>ed</strong>, gland-like staminodes (d),<br />
and 3 more functional stamens (e) in the center. The 4<br />
cells (g) <strong>of</strong> the anther (h) have flap-like valves (i), that<br />
flip up to release pollen.<br />
Found on another tree, the female flower has 6 sepals<br />
(k), 6 staminodes (l), and a single pistil with an ovary<br />
(m) containing an ovule. At maturity, the ovule is the<br />
fruit <strong>of</strong> the purple drupe (q). This fruit is enclos<strong>ed</strong> at the<br />
base by an expand<strong>ed</strong> cup (r) made up <strong>of</strong> sepals and<br />
p<strong>ed</strong>icel (s).<br />
COLOR CODE<br />
green: leaf (a), stem (u)<br />
yellow-green: sepals (b, k), stamens (c, e), p<strong>ed</strong>icel<br />
(f, p), cells (g), anther (h), valves (i),<br />
filament (j)<br />
yellow: staminodes (d, l)<br />
pale green: ovary (m), style (n), stigma (o)<br />
purple: drupe (q)<br />
r<strong>ed</strong>: cup (r), p<strong>ed</strong>icel (s), p<strong>ed</strong>uncle (t)
Water Lily Family (Nymphaeaceae)<br />
Water lilies are primitive, fresh water flowering plants.<br />
Long petioles are attach<strong>ed</strong> inside the blade margin<br />
(peltate leaf), or falsely so, permitting the leaves to float<br />
on the surface. The flower bud grows upward to the water<br />
surface on a long p<strong>ed</strong>uncle. Floating or submerg<strong>ed</strong><br />
leaves are simple and alternate and <strong>of</strong>ten have milky latex<br />
ducts. These herbaceous plants are usually perennial.<br />
There are 9 genera and over 90 species.<br />
The flower is <strong>of</strong>ten showy, single and bisexual. Flower<br />
part numbers are indefinite, a primitive characteristic,<br />
but mostly in 3’s. The sepals are usually green and the<br />
ovary is usually superior. Fruits are follicles, an aggregate<br />
<strong>of</strong> indehiscent nutlets or a berry.<br />
Of interest...ornamentals: Brasenia (water shield),<br />
Cabomba (fanwort, us<strong>ed</strong> as an oxygenator in aquaria),<br />
Nelumbo lutea (lotus lily, water chinquapin), N. nucifera<br />
(oriental sacr<strong>ed</strong> lotus), Nuphar (yellow water lily, spatterdock),<br />
Nymphaea spp. (water lilies), Victoria amazonica<br />
(Amazon water lily, giant water lily); food: rhizomes<br />
<strong>of</strong> Nelumbo pentapetala were us<strong>ed</strong> a starchy<br />
food source by native Americans.<br />
Victoria amazonica, a native <strong>of</strong> the Amazon River in<br />
South America, was nam<strong>ed</strong> after Queen Victoria <strong>of</strong><br />
England when it was first discover<strong>ed</strong> in 1801. Leaves<br />
may reach 7 feet (214 cm) in diameter. Leaf margins<br />
have upturn<strong>ed</strong> <strong>ed</strong>ges with notches that allow water to<br />
drain <strong>of</strong>f the leaves. They live along river margins in<br />
shallow lakes.<br />
White flower buds open at sunset, heating to aid in<br />
spreading their strong sweet scent. This attracts the<br />
79<br />
main pollinator, a one-inch scarab beetle, Cyclocephala<br />
hardyi. As the flower temperature falls, the scent disappears;<br />
the flower closes with beetles trapp<strong>ed</strong> inside.<br />
The next day, the now dark pink flower reopens and<br />
releases the pollen-cover<strong>ed</strong> beetles, ready to fly <strong>of</strong>f to<br />
another new white flower.<br />
Nymphaea odorata Water Lily<br />
This freshwater perennial plant has a stout underground<br />
stem (rhizome) with roots that anchor the plant in soil.<br />
Long petioles (a) make it possible for the buoyant leaf<br />
blades (b) to float on the water surface. The petiole is attach<strong>ed</strong><br />
at a cleft in the blade where veins radiate from it.<br />
Large air passages run the length <strong>of</strong> both leaf petioles<br />
and flower p<strong>ed</strong>uncles (c) making them buoyant. Specializ<strong>ed</strong><br />
parenchyma tissue with intercellular air spaces<br />
also aids water plants to float.<br />
The flower has 4 sepals (d), many petals (e), and many<br />
stamens (f). The outer whorls <strong>of</strong> stamens have smaller<br />
anther sacs and tend to be more petal-like than stamens<br />
<strong>of</strong> the inner whorls. The stamen’s filament (g) extends<br />
above the anther sacs (h). The inner, female part <strong>of</strong> the<br />
flower has a compound ovary (i) with many outwardly<br />
radiating carpels. A stigmatic surface (j, k) covers the<br />
upper portion <strong>of</strong> each carpel (l), which has numerous<br />
ovules (m) inside.<br />
After fertilization, the flower grows downward below the<br />
water surface to the mud substratum, where a manyse<strong>ed</strong><strong>ed</strong><br />
berry (n) matures. Sepals and petals disintegrate,<br />
leaving scars (o) on the outer surface.<br />
COLOR CODE<br />
tan: petiole (a), p<strong>ed</strong>uncle (c)<br />
green: blade (b)<br />
yellow-green: sepals (d), berry (n)<br />
light lavender: petals (e)<br />
dark lavender: petal tips (shad<strong>ed</strong>), stamen tips<br />
(shad<strong>ed</strong>)<br />
yellow: stamens (f), filament (g), anther<br />
sacs (h), ovary (i), stigmas (j),<br />
stigmatic surface (k), carpel (l)<br />
white: ovules (m)
Buttercup Family (Ranunculaceae)<br />
Plants in this primitive family are mostly annual or<br />
perennial herbs, but a few are woody vines. They prefer<br />
moist habitats. The leaves are usually alternate, compound,<br />
and have palmate venation. Typically, the flower<br />
is bisexual with spirally arrang<strong>ed</strong> parts. There are over<br />
50 genera and over 1800 species found in temperate<br />
and cold areas <strong>of</strong> the Northern Hemisphere.<br />
There are usually 5 sepals (but there may also be<br />
3 to many) and 5 petals or varying numbers or none.<br />
The petals sometimes serve as nectaries. There are<br />
many spirally arrang<strong>ed</strong> stamens.<br />
Pistils are 3 to many. The ovary is superior with one<br />
to many carpels and one to many ovules in parietal<br />
placentation. The fruits are follicles, achenes, berries,<br />
or capsules.<br />
Of interest...ornamentals: Aconitum (monkshood,<br />
extremely poisonous), Actaea (baneberry), Anemone<br />
(windflower), Anemonella (rue anemone), Aquilegia<br />
(columbine), Caltha (marsh marigold, cowslip), Clematis<br />
(clematis), Cimicifuga (bugbane), Coptis (golden<br />
thread), Delphinium (delphinium, larkspur), Helleborus<br />
(Christmas rose), Hepatica (hepatica), Hydrastis<br />
(golden seal), Isopyrum (false rue anemone), Nigella<br />
(love-in-a- mist), Paeonia (peony), Ranunculus (buttercup),<br />
Thalictrum (meadow rue), Trollius (globe flower).<br />
Ranunculus pensylvanicus Buttercup<br />
This wild plant is an erect, branch<strong>ed</strong> perennial growing<br />
30 to 70 centimeters high. Its hairy stem (a) has<br />
alternate leaves (b, c), which are deeply lob<strong>ed</strong> forming<br />
three leaflets (d) that have tooth<strong>ed</strong> margins and palmate<br />
venation.<br />
The flower (f) has reflex<strong>ed</strong> sepals (g) that are longer<br />
than the petals (h). Numerous stamens (i) surround the<br />
base <strong>of</strong> a central aggregate <strong>of</strong> numerous pistils (j). The<br />
carpel <strong>of</strong> each pistil has one ovule (k). At maturity, the<br />
fruit consists <strong>of</strong> an aggregate <strong>of</strong> achenes (m).<br />
80<br />
COLOR CODE<br />
light green: stem (a), pistils (j), ovules (k)<br />
green: petioles (b), leaflets (d), sepals (g),<br />
p<strong>ed</strong>uncle (l)<br />
tan: roots (e), achenes (m)<br />
yellow: flower (f), petals (h), stamens (i)
Witch Hazel Family<br />
(Hamamelidaceae)<br />
Trees and shrubs are represent<strong>ed</strong> in this family. There<br />
are 23 genera and about 100 species, mostly found<br />
in Asia. The alternate leaves are simple, deciduous or<br />
evergreen, and have deciduous, r<strong>ed</strong>uc<strong>ed</strong> leaves (stipules)<br />
at the petiole base. Often, star-like (stellate) or<br />
tree-like (dendrite) hairs occur on leaf surfaces.<br />
Flowers are bisexual or unisexual on the same plant<br />
(monoecious) or on separate plants (dioecious).<br />
Flower parts include 4-5 sepals, 4-5 petals or none,<br />
2-8 stamens, and a single pistil.<br />
Significant flower characteristics are a pistil with 2 styles<br />
that curve away from each other and an ovary consisting<br />
<strong>of</strong> 2 carpels and chambers that develop into a woody<br />
capsule.<br />
Of interest...extract: Hamamelis virginiana (witch<br />
hazel); lumber: Altingia excelsa (rasamala), Bucklandia,<br />
Liquidambar styraciflua (sweet gum); ornamentals:<br />
Corylopsis (winter hazel), Disanthus, Distylium,<br />
Fothergilla (fothergilla, witch alder), Hamamelis viriginiana<br />
(common witch hazel), H. vernalis (vernal witch<br />
hazel), Liquidambar styraciflua (sweet gum, with multicolor<strong>ed</strong><br />
autumn foliage), Loropetalum, Parrotia, Sinowilsonia.<br />
Hamamelis virginiana Common Witch Hazel<br />
Fork<strong>ed</strong> branches <strong>of</strong> this shrub or small tree were us<strong>ed</strong><br />
in the past as divining rods for water-well sites. An<br />
81<br />
astringent compound is extract<strong>ed</strong> from leaves, stems,<br />
and bark for use in ointments and lotions. Leaves<br />
(a) have an uneven blade base (b) and microscopic<br />
dentrite hairs on the surfaces.<br />
In this autumn-flowering species, two-locul<strong>ed</strong> capsules<br />
(d) mature from the previous year’s flowers at the same<br />
time as flower buds (e) are opening. As the capsule<br />
opens, two shiny se<strong>ed</strong>s (f) are forcibly eject<strong>ed</strong>.<br />
Hamamelis vernalis Vernal Witch Hazel<br />
Unlike the common witch hazel, this shrub’s flowers<br />
open in the spring. Stemless (sessile), bisexual flowers<br />
form in small clusters. Below each flower are hairy<br />
bracts (g). The flower parts include 4 triangular sepals<br />
(h), 4 strap-shap<strong>ed</strong> petals (i), 4 stamens (j), which open<br />
(dehisce) by upward-turning anther valves (k), and a<br />
single pistil (m).<br />
The pistil has 2 styles (n) and stigmas (o) and a halfinferior<br />
ovary consisting <strong>of</strong> 2 carpels (p). In each carpel<br />
is an ovule (q) with axile placentation (see 28). After<br />
fertilization, the ovule will form the se<strong>ed</strong> that is later<br />
eject<strong>ed</strong>. Surrounding the ovary are 4 nectar flaps (r),<br />
which attract insect pollinators.<br />
COLOR CODE<br />
green: leaves (a), pistil (m)<br />
tan: stem (c), capsule (d), flower buds (e),<br />
bracts (g), p<strong>ed</strong>uncle (s)<br />
dark brown: se<strong>ed</strong>s (f)<br />
dark r<strong>ed</strong>: sepals (h)<br />
yellow: petals (i), stamens (j), anther valves (k),<br />
filament (l), nectary (r)<br />
light green: style (n), stigma (o), carpel (p), ovule (q)
Elm Family (Ulmaceae)<br />
There are only about 16 genera in this family <strong>of</strong> trees<br />
and shrubs. Most <strong>of</strong> the genera have unisexual flowers.<br />
The alternate leaves usually have tooth<strong>ed</strong> (dentate)<br />
margins, uneven blade bases, and deciduous stipules.<br />
Parts <strong>of</strong> the flower include fus<strong>ed</strong> sepals <strong>of</strong> 4-8 lobes,<br />
stamens the same number as sepal lobes, and one pistil.<br />
The flower has no nectaries and no petals, but does<br />
have abundant pollen, that is wind-carri<strong>ed</strong> to the pistil’s<br />
plumose stigmas. A single ovule develops in a superior<br />
ovary consisting <strong>of</strong> two fus<strong>ed</strong> carpels. Fruit types are a<br />
wing<strong>ed</strong> samara, drupe, or nutlet.<br />
Of interest...lumber: Ulmus spp. (elms), Planera<br />
abelica (false sandalwood); ornamentals: Ulmus<br />
glabra (Scotch elm), U. parvifolia (Chinese elm); we<strong>ed</strong><br />
tree: Ulmus pumila (Siberian elm).<br />
Ulmus americana American Elm<br />
This once common American tree has been greatly r<strong>ed</strong>uc<strong>ed</strong><br />
in numbers by the Dutch elm disease caus<strong>ed</strong> by<br />
an ascomycete fungus, Ceratocystis ulmi (see 48).<br />
The leaf has a short petiole (a), an uneven blade base<br />
(b) and doubly serrat<strong>ed</strong> margins (c). Its upper surface<br />
feels rough to the touch, while the lower surface is<br />
smooth. At the end <strong>of</strong> each growing season, the terminal<br />
bud falls <strong>of</strong>f. The first lateral bud then forms a<br />
false “terminal” bud (d). This accounts for the zigzag<br />
stem (f) in elms.<br />
In the spring, clusters <strong>of</strong> tiny flowers (g) dangle out from<br />
the bud scales (h) before the leaves expand. Flowers<br />
are group<strong>ed</strong> in clusters (fascicles, i)<strong>of</strong>3or4.Thebisexual<br />
flower has 8 lobes (j) on join<strong>ed</strong> sepals (k) and<br />
8 stamens (m) with the anthers (o) extend<strong>ed</strong> on long<br />
filaments (p).<br />
The pistil produces one ovule in the ovary (q) and has<br />
many stigmatic hairs along 2 styles (r). The fruit is a<br />
wing<strong>ed</strong> (s) samara with a single se<strong>ed</strong> (t). It is winddispers<strong>ed</strong><br />
in the spring.<br />
Celtis tenuifolia Dwarf Hackberry<br />
This small tree has variably margin<strong>ed</strong> (entire and<br />
tooth<strong>ed</strong>) leaves (v) with lob<strong>ed</strong> veins (w) and a drupe<br />
(x) type fruit which matures in the autumn.<br />
82<br />
COLOR CODE<br />
dark green: petiole (a), blade (b)<br />
tan: bud (d), lateral bud (e), stem (f),<br />
sepals (u)<br />
orange: sepal lobes (j)<br />
r<strong>ed</strong>: flowers (g), join<strong>ed</strong> sepals (k)<br />
yellow-green: sepal base (l)<br />
brown: bud scales (h), se<strong>ed</strong> (t)<br />
yellow: stamens (m), pollen (n), anther (o)<br />
white: filament (p), style (r)<br />
light green: ovary (q)<br />
yellow-tan: samara (s)<br />
green: leaf (v)<br />
orange-r<strong>ed</strong>: drupe (x)
Beech Family (Fagaceae)<br />
A nut fruit partially enclos<strong>ed</strong> in basal bracts (acorn,<br />
beechnut, chestnut) is the most familiar characteristic<br />
<strong>of</strong> this family <strong>of</strong> eight genera. Genera are Fagus<br />
(beech), Castanea (chestnut), Quercus (oak), Lithocarpus,<br />
Noth<strong>of</strong>agus, Castanopsis, Trigonobalanus, and<br />
Chrysolepsis. Fossils indicate an origin during the middle<br />
<strong>of</strong> the Cretaceous.<br />
Alternate, simple leaves have lob<strong>ed</strong>, tooth<strong>ed</strong>, or entire<br />
margins and deciduous stipules. The flowers are usually<br />
unisexual and wind-pollinat<strong>ed</strong>.<br />
The male flower occurs in catkins or singly and has 4–7<br />
sepals, 4–40 stamens, and a vestigial pistil. The female<br />
flower can be single in a cup <strong>of</strong> bracts or in a cluster <strong>of</strong><br />
2–3 flowers, which may have bracts. Fus<strong>ed</strong> sepals <strong>of</strong> the<br />
female flower have 4–6 lobes. The pistil has an inferior<br />
ovary <strong>of</strong> 3–6 carpels, chambers (locules), and styles.<br />
Two ovules occur in axil placentation. They develop in<br />
each chamber, in which one develops and the other<br />
aborts.<br />
Of interest...hardwood lumber: Castanea spp.<br />
(chestnuts), Fagus spp. (beeches), Quercus spp. (oaks;<br />
in the Unit<strong>ed</strong> States, oaks are the second most important<br />
source <strong>of</strong> lumber after conifers); food: nuts<br />
<strong>of</strong> chestnut, beech and oaks. Native Americans us<strong>ed</strong><br />
acorns to make bread. Acorns are also an important<br />
source <strong>of</strong> food for wild animals and birds. Commercially,<br />
Castanea sativa (sweet chestnut), <strong>of</strong> southern<br />
Europe, is a source <strong>of</strong> nuts for purees, stuffings<br />
and stews; cork: bark <strong>of</strong> Quercus suber (cork oak) is<br />
stripp<strong>ed</strong> and dri<strong>ed</strong> to produce cork; ornamentals: Castanea<br />
spp. (chestnuts), Fagus spp. (beeches), Lithocarpus<br />
(tanoak), Quercus spp. (oaks); plant diseases:<br />
Castanea dentata (American chestnut) has been<br />
83<br />
devastat<strong>ed</strong> to near extinction by chestnut blight, caus<strong>ed</strong><br />
by an ascomycete fungus, Endothia parasitica (see 48);<br />
sudden oak death is a disease caus<strong>ed</strong> by Phytophthora<br />
ramorum, an oomycete (see 46).<br />
Quercus spp. Oaks<br />
Oak forms vary from small shrubs to large trees. They<br />
have deep roots and occur in dry sites. There are over<br />
400 species and many hybrids between species. Oaks<br />
are easily identifi<strong>ed</strong>, even in winter, by the cluster <strong>of</strong><br />
buds (a) at the end <strong>of</strong> the stem (c). The leaves (e, f, g)<br />
are deciduous or persistent. Young oaks tend to retain<br />
their leaves over winter and sh<strong>ed</strong> them in spring.<br />
Oaks are divid<strong>ed</strong> into two groups: white oaks and r<strong>ed</strong><br />
oaks. White oaks have leaves with round<strong>ed</strong> lobes and<br />
acorns that mature in the autumn <strong>of</strong> their first year. R<strong>ed</strong><br />
oak leaves have bristle tips and acorns that mature in<br />
the autumn <strong>of</strong> the second year.<br />
Oaks are monoecious with separate male and female<br />
flowers on one tree. Male flowers form in pendant clusters,<br />
an indication <strong>of</strong> wind pollination. The male flowers<br />
(h) open before or with expanding leaves (k). The male<br />
flower has four to seven sepals (m) and six to twelve<br />
stamens (n).<br />
The female flowers form in the axils <strong>of</strong> new spring<br />
leaves. This flower has join<strong>ed</strong> sepals <strong>of</strong> 6 lobes (o) and<br />
a pistil consisting <strong>of</strong> 3 styles (p) and 3 stigmas (q). The<br />
ovary is enclos<strong>ed</strong> in a whorl <strong>of</strong> bracts (involucre, r)<br />
which matures into a scaly cup (s). The fruit <strong>of</strong> cup and<br />
nut (t), commonly known as an acorn, may mature in<br />
one or two seasons.<br />
COLOR CODE<br />
tan: buds (a, b), leaf scar (d), leaf (g),<br />
cup (s)<br />
brown: stem (c), p<strong>ed</strong>uncle (l)<br />
green: leaf (e)<br />
r<strong>ed</strong>: leaf (f)<br />
yellow: male flowers (h)<br />
light tan: stem (i), sepals (m), nut (t)<br />
tan-orange: bud scales (j)<br />
grey-green: young leaves (k)<br />
yellow-green: stamens (n)<br />
light green: sepals (o), styles (p), stigmas (q),<br />
involucre (r)
Birch Family (Betulaceae)<br />
Trees and shrubs that comprise this family have<br />
deciduous leaves. Leaves are alternate and simple and<br />
have saw-tooth (serrate) margins. Stipules are present<br />
at petiole bases. The bark is prominently mark<strong>ed</strong> by<br />
lenticels (openings for gas exchange) and in some<br />
species it peels <strong>of</strong>f in thin papery layers. There are<br />
six genera with about 170 species. Genera are Alnus<br />
(alder), Betula (birch), Carpinus (hornbeam), Corylus<br />
(hazelnut, filbert), Ostrya (hop-hornbeam), and<br />
Ostryopsis.<br />
The flowers in this family are borne in catkin-like clusters<br />
<strong>of</strong> cymules. Many cymules make up a cyme (cluster <strong>of</strong><br />
clusters). Each cymule has two to three flowers and<br />
several bracts. Clusters <strong>of</strong> male flowers and clusters <strong>of</strong><br />
female flowers occur on the same plant (monoecious).<br />
The male flower may have 4 tepals (sepals and petals<br />
that look alike) with 2–20 stamens per cyme. The female<br />
flower has a single pistil with an inferior ovary, 2<br />
styles, and 2 stigmas. These spring flowers utilize wind<br />
for pollination and produce a nutlet or a wing<strong>ed</strong> samara<br />
fruit.<br />
Of interest...lumber: Betula (birch), Alnus oregona<br />
(r<strong>ed</strong> alder), Ostrya (hop-hornbeam); charcoal: Alnus<br />
(alder), Betula; food: Corylus (hazelnut, filbert); ornamentals:<br />
Betula papyrifera (paper birch, white birch), B.<br />
pendula (European white birch), B. nigra (river birch),<br />
Corylus, Ostrya.<br />
Betula pendula European white Birch<br />
This tree, <strong>of</strong>ten us<strong>ed</strong> as an ornamental, has several<br />
trunks typically occurring together in a clump. The white<br />
paper bark has dark horizontal lenticular markings and<br />
peels <strong>of</strong>f in layers. Trees have graceful spreading or<br />
pendant branches.<br />
The flowering shoot (a) shows the leaves (b) with serrat<strong>ed</strong><br />
(tooth<strong>ed</strong>) margins and stipules (c). Male flower<br />
clusters (catkins, d) are pendant, while the female cluster<br />
(e) is smaller and upright. The male cyme shown has<br />
7 stamens enclos<strong>ed</strong> by bracts (f). At the end <strong>of</strong> the stamen’s<br />
filament (g), 2 anther sacs (h) separate and open<br />
in longitudinal slits. Three pistils and 3 bracts (i) make<br />
up the female cymule. The pistil has an inferior ovary<br />
(j) and 2 styles (k).<br />
At fruiting time, the female cluster disintegrates, freeing<br />
the samaras (l) from the woody bracts (m).<br />
84<br />
COLOR CODE<br />
tan: stem (a), male cluster (d), bract (f),<br />
se<strong>ed</strong> (n)<br />
green: leaves (b), stipules (c), female cluster (e)<br />
yellow: filaments (g), anther sacs (h), samara (l)<br />
dark green: bract (i)<br />
white: ovary (j), styles (k)<br />
brown: bracts (m)
Cactus Family (Cactaceae)<br />
Native only to the Western Hemisphere, cacti have<br />
fleshy stems with spines or barb<strong>ed</strong> hairs (glochids) arrang<strong>ed</strong><br />
in cluster sites (areoles). Spines may occur as<br />
hairs, hooks, bristles, and be short, straight, curv<strong>ed</strong>,<br />
long. They shade the plant and r<strong>ed</strong>uce drying effects <strong>of</strong><br />
wind. The usually solitary flower has numerous sepals<br />
and petals that look alike (tepals) and the fruit type is<br />
a berry.<br />
As the stems usually function in photosynthesis, the<br />
leaves are mostly small, scale-like, or absent. Root systems<br />
are usually extensive and close to the soil surface,<br />
adapt<strong>ed</strong> to absorb rainwater quickly.<br />
To prevent water loss in dry climate conditions, there is<br />
an outer surface cuticle that is thick and waxy. Water<br />
absorb<strong>ed</strong> by the roots is stor<strong>ed</strong> in tissue as mucilaginous<br />
sap.<br />
Of interest...cacti number about 80 genera with<br />
at least 2,000 species; a few <strong>of</strong> the ornamentals<br />
are: Echinocereus, Echinopsis, Ferocactus sp. (barrel<br />
cactus), Lemaireocereus thurberi (organpipe cactus),<br />
Mammillaria (pincushion cactus), Neoporteria, Opuntia<br />
versicolor (staghorn cactus), Peniocereus greggii<br />
(night blooming cereus), Pereskia (rose cactus),<br />
Rubutia (r<strong>ed</strong> crown cactus), Schlumbergera bridgesii<br />
(Christmas cactus); food: Opuntia (prickly-pear) has<br />
<strong>ed</strong>ible berries, that can be made into jam; young stems,<br />
“pads,” are eaten as food, and can be propagat<strong>ed</strong> by<br />
drying overnight, then plac<strong>ed</strong> in sand to root; consider<strong>ed</strong><br />
a we<strong>ed</strong> pest on rangeland; many are endanger<strong>ed</strong>:<br />
Carnegiea gigantea (saguaro, see 36).<br />
There are many forms <strong>of</strong> cacti: single, clumps, low to the<br />
ground, upright, even tall as trees such as Carnegiea<br />
gigantea (saguaro). At an age <strong>of</strong> 200 years saguaro<br />
can reach 50 feet (152 meters) high and weigh 8 tons<br />
85<br />
(45 tonnes). “Skeletons” <strong>of</strong> dead saguaro stem look like<br />
cylinders <strong>of</strong> woody rods. People <strong>of</strong> the desert use them<br />
as fence-building material.<br />
Birds nest in cacti. Even though cactus spines deter<br />
contact, squirrels and other rodents, rabbits, and peccaries<br />
eat the fleshy stems.<br />
The cactus craze began in the 1800’s. Hobbyists collect<br />
different types <strong>of</strong> cacti. Cacti are easy to grow, ne<strong>ed</strong>ing<br />
sparse water, sandy soil, and produce beautiful flowers<br />
in many colors. And, they are perennials.<br />
Cacti are transport<strong>ed</strong> to other desert areas <strong>of</strong> the world.<br />
In some places they are serious invaders, displacing<br />
native species.<br />
Opuntia decumbens Prickly-pear<br />
The fleshy stem (a) is flat. A stem node in cacti is call<strong>ed</strong><br />
an areole (b). From it emerges a leaf (c), if present,<br />
spines (d) and glochids (r<strong>ed</strong>uc<strong>ed</strong> short shoots), hairs<br />
(e), and the flower.<br />
Schlumbergera truncata Thanksgiving Cactus<br />
On this plant, the stems (f) are flat and form a branching<br />
pattern as new stems emerge from areoles at ends<br />
<strong>of</strong> the stem pieces. With short daylength periods, flowers<br />
are produc<strong>ed</strong> (see 26). The flower has numerous<br />
tepals (g), numerous stamens (h), and a single pistil.<br />
The stigma (i) <strong>of</strong> the pistil extends beyond the stamens.<br />
Pereskia grandifolia Rose Cactus<br />
This cactus plant has round fleshy stems (j) with spines<br />
(k) and a large thicken<strong>ed</strong> simple leaf (l) emerging from<br />
the areole.<br />
COLOR CODE<br />
light green: leaf (c)<br />
green: stem (a, f, m j), leaf (l)<br />
yellow: areoles (b), spines (d, k), hairs (e)<br />
r<strong>ed</strong>: tepals (g)
Cactus Family (continu<strong>ed</strong>)<br />
Mammillaria prolifera Pincushion Cactus<br />
This perennial herb from North American deserts is<br />
globe-shap<strong>ed</strong>. Areoles (a), with hairs (b) and glochids<br />
(c), occur rais<strong>ed</strong> on fleshy tubercles (d).<br />
The typically bisexual cactus flower consists <strong>of</strong> numerous<br />
tepals (e), numerous stamens (f), and one pistil<br />
with an inferior ovary (g) consisting <strong>of</strong> three fus<strong>ed</strong><br />
carpels forming one chamber (locule) in which numerous<br />
ovules (h) develop in parietal placentation. The pistil<br />
has one style (i) and a branch<strong>ed</strong> stigma (j).<br />
The fruit is a r<strong>ed</strong> berry (k) with black se<strong>ed</strong>s (l).<br />
Of interest...houseplants: there are many species to<br />
choose from with flower colors from white to cream,<br />
r<strong>ed</strong>s, pinks and yellows. They are easy to grow in<br />
porous, sandy/gravely soil. Some include Mammillaria<br />
albescens (greenish-white flowers), M. bocasana ‘Inermis’<br />
(snowball cactus, yellow flowers), M. columbiana<br />
(deep pink flowers), M. compressa (purplish-r<strong>ed</strong> flowers),<br />
M. elegans (r<strong>ed</strong> flowers),M. geminispina (carmine<br />
flowers), M. heyderi (coral cactus, white with r<strong>ed</strong> or<br />
pink flowers), M. magnimamma (cream-white flowers),<br />
M. zeilmanniana (rose-pincushion, purple flowers).<br />
86<br />
COLOR CODE<br />
tan: glochids (c)<br />
pale green: tubercles (d)<br />
yellow: tepals (e)<br />
white: stamens (f), ovules (h), style (i),<br />
stigma (j)<br />
r<strong>ed</strong>: berry (k)
Pink Family (Caryophyllaceae)<br />
Leaves <strong>of</strong> plants in this family are usually opposite and<br />
join<strong>ed</strong> at the base on the stem. The flower’s ovary has<br />
2–5 carpels join<strong>ed</strong> to form one chamber (locule) with<br />
the ovules usually in free-central placentation (see 28<br />
and Dianthus). There are more than 2,000 species.<br />
This is one <strong>of</strong> the families in the subclass Carophyllidae<br />
that does not have betalain pigments (see 75).<br />
Instead, there are anthocyanins (see 4). These Temperate<br />
Zone plants are mainly annual or perennial<br />
herbs, or sometimes shrubs. The fruit is usually a onechamber<strong>ed</strong><br />
capsule with valves.<br />
Of interest...ornamentals: Arenaria (sandwort),<br />
Dianthus barbatus (sweet William), D. caryophyllus<br />
(carnation), D. gratianopolitanus (ch<strong>ed</strong>dar pink), D.<br />
plumarius (cottage pink), Gypsophila (baby’s-breath),<br />
Lychnis chalc<strong>ed</strong>onica (Maltese Cross), L. coronaria<br />
(rose campion, dusty miller), Silene acaulis (cushion<br />
pink); we<strong>ed</strong>s: Cerastrium (mouse-ear chickwe<strong>ed</strong>),<br />
Scleranthus, Stellaria (chickwe<strong>ed</strong>, starwort), Spergula<br />
arvensis (corn spurry), Silene pratensis (white<br />
cockle); prairie plants: Dianthus armeria (Deptford<br />
pink), Silene dioica (r<strong>ed</strong> campion), S. latifolia<br />
(evening campion), S. regia (royal catchfly), S. stellata<br />
(starry catchfly), S. virginica (fire pink); poisonous:<br />
87<br />
Agrostemma githago (corn cockle), Crymaria pachyphylla,<br />
Saponaria vaccaria (cow cockle), S. <strong>of</strong>ficinalis<br />
(bouncing Bet).<br />
Dianthus Pink<br />
Plants in this genus are annual or biennial herbs. The<br />
arrangement <strong>of</strong> leaves (a) on the stem (b) is decussate,<br />
which means 4 pairs <strong>of</strong> opposite leaves alternate at right<br />
angles. Leaf bases form swollen nodes (c) on the stem.<br />
The bisexual flower has 5 join<strong>ed</strong> sepals (d) and overlapping<br />
bracts (e) that prevent nectar-robbing bees from<br />
biting into the flower. The illustration <strong>of</strong> the capsule<br />
shows the sturdy construction. The 5 petals (f) are<br />
notch<strong>ed</strong> or “pink<strong>ed</strong>” at the <strong>ed</strong>ges as if cut by pinking<br />
shears and consist <strong>of</strong> claw (g), corona (h) and limb (i).<br />
Ten stamens (j) have 5 join<strong>ed</strong> filaments at the base.<br />
The pistil has a superior ovary (k) with carpels unit<strong>ed</strong><br />
into one locule in which many ovules (l) are attach<strong>ed</strong> in<br />
free-central placentation. Two styles (m) elongate into<br />
feathery (plumose) stigmas (n).<br />
The capsule is enclos<strong>ed</strong> by sepals and bracts and splits<br />
into valves (o) adapt<strong>ed</strong> to release the se<strong>ed</strong>s.<br />
COLOR CODE<br />
dark green: stem (b)<br />
green: leaves (a), nodes (c), sepals (d), bracts<br />
(e)<br />
r<strong>ed</strong>: petals (f), claw (g), corona (h), limb (i)<br />
yellow: stamens (j)<br />
light green: ovary (k)<br />
white: ovules (l), style (m), stigmas (n)<br />
tan: valves (o)
Goosefoot Family (Chenopodiaceae)<br />
Plants in this family are mainly salt-tolerant annual or<br />
perennial herbs with vesicular (glandular) hairs on the<br />
leaves that store salt as sodium or potassium chloride.<br />
Betalain pigments are also present (see 4, 75). This<br />
family has about 100 genera and about 1500 species.<br />
Tiny, wind-pollinat<strong>ed</strong> flowers form in dense clusters. The<br />
usually bisexual flower has 5 join<strong>ed</strong> sepals or none, 5<br />
stamens, and a single pistil. In the superior ovary is one<br />
chamber (locule) containing one ovule that develops<br />
into a nutlet fruit.<br />
Of interest...food: Beta vulgaris (beet, eaten as a<br />
vegetable and also as a sugar beet variety that is a<br />
source <strong>of</strong> sugar), Beta vulgaris variety Cicla (Swiss<br />
chard, rhubarb chard), Chenopodium quinoa (quinoa),<br />
Spinacia oleracea (spinach), Tetragonia expansa (New<br />
Zealand spinach); wild food: Chenopodium album<br />
(lamb’s quarters); ornamental: Chenopodium amaranticolor,<br />
Kochia (cypress spurge).<br />
Chenopodium album Lamb’s Quarters<br />
This annual herb grows to one meter in height and is<br />
found in dry, waste places and as a common garden<br />
we<strong>ed</strong>. The 5-sid<strong>ed</strong> stem (a) has alternate, “goose-foot”shap<strong>ed</strong><br />
leaves (b) with white spots <strong>of</strong> salt-containing<br />
glands (c) on the lower surfaces (d).<br />
Spikes <strong>of</strong> sessile green flowers (e) produce black, shiny<br />
nutlets. The flower consists <strong>of</strong> 5, gland-cover<strong>ed</strong> sepals<br />
(f), 5 stamens (g) and a single pistil with a superior ovary<br />
(h), and 2 styles (i).<br />
Chenopodium capitatum Strawberry-blite<br />
Also an annual, this plant is found along roadsides and<br />
in clear-cut and burn<strong>ed</strong>-over forest areas. Its alternate<br />
“goose-foot” leaves (k) lack salt-containing glands.<br />
Round clusters <strong>of</strong> flowers (l) are bright r<strong>ed</strong>, the color<br />
<strong>of</strong> the flower’s fleshy sepals. Dull black nutlets (m) are<br />
produc<strong>ed</strong>.<br />
88<br />
COLOR CODE<br />
green: stems (a, j), leaf upper surface (b),<br />
leaves (k)<br />
pale green: leaf lower surface (d), flowers (e),<br />
sepals (f), ovary (h), styles (i)<br />
yellow: stamens (g)<br />
r<strong>ed</strong>: flowers (l)<br />
black: nutlet (m)
Buckwheat Family (Polygonaceae)<br />
Most <strong>of</strong> the family’s plants are we<strong>ed</strong>y with small flowers<br />
and are adapt<strong>ed</strong> to many different soil types. The stem<br />
nodes have a sheathing membrane consisting <strong>of</strong> two<br />
fus<strong>ed</strong> stipules, call<strong>ed</strong> an ocrea. While mainly herbs,<br />
there are also a few shrubs, trees, and vines in this<br />
family. There are about 30 genera.<br />
Small, wind-pollinat<strong>ed</strong> flowers are borne in clusters or<br />
in heads. Usually the flower is bisexual and with a variable<br />
number <strong>of</strong> parts <strong>of</strong> 3-5 sepals and petals that look<br />
alike (call<strong>ed</strong> tepals), 6-9 stamens, and a single pistil.<br />
The superior ovary <strong>of</strong> fus<strong>ed</strong> carpels has one chamber<br />
(locule) with one ovule which develops into an achene<br />
fruit (see dry fruit types, 38)<br />
Of interest...food: Fagopyrum esculentum (buckwheat),<br />
Rheum rhaponticum (rhubarb), Rumex acetosa<br />
(garden sorrel); ornamentals: Antigonon (mountainrose<br />
vine), Atraphaxis frutescens, Coccoloba uvifera<br />
(sea grape), Eriogonum, Muehlenbeckia axillaris, Persicaria<br />
bistorta ‘Superba’ (knotwe<strong>ed</strong>), Polygonum aubertii<br />
(silver lace vine), P. orientale (prince’s feather), P.<br />
sachalinense (sacaline), Rheum palmatum (Chinese<br />
rhubarb, a m<strong>ed</strong>icinal plant), Rumex hydrolapathum;<br />
we<strong>ed</strong>s: Polygonum spp. (knotwe<strong>ed</strong>s, smartwe<strong>ed</strong>s, wild<br />
buckwheat), Polygonum convolvulus (black bindwe<strong>ed</strong>),<br />
Rumex acetosella (sheep sorrel, r<strong>ed</strong> sorrel, an <strong>ed</strong>ible<br />
plant with tart-tasting, arrowhead-shap<strong>ed</strong> leaves), R.<br />
crispus (curly dock).<br />
Polygonum persicaria Lady’s Thumb, R<strong>ed</strong>leg<br />
Lady’s thumb is known as a smartwe<strong>ed</strong> for its sap, which<br />
irritates, “smarts,” on contact with human eye and nose<br />
tissues. This annual’s stems (a) have a joint<strong>ed</strong> appearance.<br />
Polygonum means “many joints” or “knees,” the<br />
name given for the knobby stems with swollen nodes.<br />
At each node (b) is an ocrea (c) fring<strong>ed</strong> with bristles.<br />
Short-petiol<strong>ed</strong>, linear leaves (d) have a spot (e) <strong>of</strong> dark<br />
green pigmentation near the center, the so-call<strong>ed</strong> lady’s<br />
thumb-print.<br />
Pink flower clusters (f) have a minute membranous<br />
sheath (ocreola, g) at the base <strong>of</strong> inner clusters. The<br />
small flower has 5 tepals (h), 2 enclosing the inner 3;<br />
8 stamens (i); and a single pistil (j) with 2 stigmas (k).<br />
The fruit is an achene that may be lentil-shap<strong>ed</strong> (l) or<br />
3-sid<strong>ed</strong> (m).<br />
89<br />
COLOR CODE<br />
green: stem (a), leaf (d)<br />
light green: ocrea (c), ocreola (f), pistil (j)<br />
dark green: spot (e)<br />
pink: flowers (f), tepals (h)<br />
white: stamens (i)<br />
black: achene (l)<br />
tan: achene (m)
Mallow Family (Malvaceae)<br />
The flower’s column <strong>of</strong> fus<strong>ed</strong> staminal filaments is a<br />
common feature in this family (see 29). The leaves are<br />
alternate, simple, entire or variously lob<strong>ed</strong> with palmate<br />
venation. Sap is <strong>of</strong>ten mucilaginous. There are about<br />
80 genera <strong>of</strong> herbs, shrubs and trees.<br />
Usually the flower is bisexual with 5 valvate sepals, 5<br />
separate petals, numerous stamens, and a single pistil<br />
with 2-many carpels. Fruit types include a loculicidal<br />
capsule, <strong>of</strong>ten with hairy (comose) se<strong>ed</strong>s as in cotton,<br />
a schizocarp, and a berry (see 38, 39).<br />
Of interest...crops: Gossypium hirsutum (cotton, cottonse<strong>ed</strong><br />
oil), Hibiscus esculentus (okra); ornamentals:<br />
Abutilon (flowering maple), Althea rosea (hollyhock),<br />
Callirhoe (poppy mallow), Hibiscus moscheutos (common<br />
rose mallow, swamp mallow, mallow rose), M.<br />
rosa-sinensis (rose-<strong>of</strong>-China, see 29), Malope, Malva<br />
alcea (hollyhock mallow), M. moschata (musk mallow),<br />
Sidalcea malviflora (prairie mallow, miniature hollyhock);<br />
we<strong>ed</strong>s: Abutilon theophrasti (velvet-leaf), Malva<br />
neglecta (common mallow, cheese we<strong>ed</strong>).<br />
Abutilon × hybridum Flowering Maple<br />
This plant is a tropical woody shrub, hybridiz<strong>ed</strong> in cultivation<br />
for its speckl<strong>ed</strong> (a) leaves and showy flowers.<br />
Resembling maple leaves (maple family, see 105), the<br />
90<br />
blades (b) are palmately lob<strong>ed</strong> and vein<strong>ed</strong>; the petioles<br />
(c) are long.<br />
Showy orange flowers have 5 join<strong>ed</strong> sepals (d), which<br />
separate into valves and 5 petals (e). Anthers (f) extend<br />
from the center <strong>of</strong> the flower.<br />
In the vertical section <strong>of</strong> the flower, the column (g)<br />
<strong>of</strong> fus<strong>ed</strong> staminal filaments (monadelphous condition)<br />
is shown. Anthers (h) are separate at the top <strong>of</strong> the<br />
column. Within the column is the pistil’s style (i) and,<br />
emerging above the anthers, there are 5 stigmas (j).<br />
The superior ovary (k) is compos<strong>ed</strong> <strong>of</strong> 5 fus<strong>ed</strong> carpels,<br />
and has numerous ovules (l).<br />
Althea rosea Hollyhock<br />
The numerous carpels <strong>of</strong> a compound ovary produce<br />
a schizocarp fruit (see 38) <strong>of</strong> se<strong>ed</strong><strong>ed</strong> mericarps (m)<br />
attach<strong>ed</strong> to a central axis and enclos<strong>ed</strong> by persistent<br />
sepals (n). When the sepals wither, the mericarps separate<br />
from the axis.<br />
Gossypium hirsutum Cotton<br />
A cotton “boll” is a loculicidal capsule (o) <strong>of</strong> 4 carpels<br />
that split to release hair-cover<strong>ed</strong> (p) se<strong>ed</strong>s (q).<br />
COLOR CODE<br />
yellow: speckles (a)<br />
green: leaf blades (b), petioles (c)<br />
pale green: sepals (d, n), ovary (k), style (i)<br />
dark r<strong>ed</strong>: stigmas (j)<br />
orange: petals (e)<br />
pale orange: column (g), anthers (f, h)<br />
white: hairs (p), ovules (l)<br />
tan: mericarps (m), se<strong>ed</strong> (q)<br />
brown: capsule (o)
Pitcher-plant Family (Sarraceniaceae)<br />
Although there are only three genera in this family, these<br />
perennial herbs <strong>of</strong> bogs are <strong>of</strong> interest for their unusual<br />
insect-trap leaves. Forming in a basal rosette, the<br />
fluid in the modifi<strong>ed</strong> leaves digest insects for nutritional<br />
nitrogen.<br />
The bisexual flower consists <strong>of</strong> 4-5 sepals, 5 petals or<br />
none, numerous stamens, and a single pistil. The style<br />
is lob<strong>ed</strong> or expands into an umbrella-shape. A loculicidal<br />
capsule is form<strong>ed</strong> from 3-5 carpels.<br />
Of interest...as novelty ornamentals, pitcher-plant<br />
genera are: Darlingtonia (native to California and<br />
Oregon), Heliamphora (native to northern South<br />
American), and Sarracenia (native to eastern North<br />
America).<br />
Sarracenia purpurea Pitcher-plant<br />
Early in leaf development, the blade forms a tube with<br />
the upper leaf surface on the outside and the hairy<br />
lower surface on the inside. Within the leaf tube (a), with<br />
downward-point<strong>ed</strong> hairs (b), is a solution (c) <strong>of</strong> rainwater<br />
and enzymes in which insects drown and are digest<strong>ed</strong>.<br />
The leaf consists <strong>of</strong> petiole (d) and blade tube (e), wing<br />
(f), and lip (g). It is pale green with r<strong>ed</strong> veins (h).<br />
Appearing as a hanging umbrella cover<strong>ed</strong> with flaps,<br />
the flower towers above the leaves on a long p<strong>ed</strong>uncle<br />
(i). The flaps are 5 sepals (j). In the habit drawing, the 5<br />
petals (k) and numerous stamens (l) have been sh<strong>ed</strong>.<br />
The flower structure drawing shows their location. The<br />
pistil consists <strong>of</strong> a superior ovary (m) compos<strong>ed</strong> <strong>of</strong> 5<br />
carpels (n) with ovules (o) in axile placentation, and an<br />
expand<strong>ed</strong>, umbrella-shape style (p, q) with 5 stigmatic<br />
tips (r).<br />
91<br />
COLOR CODE<br />
r<strong>ed</strong>: hairs (b), veins (h), sepals (j), petal (k)<br />
light green: petiole (d), tube (e), wing (f), lip (g),<br />
p<strong>ed</strong>uncle (i), style (p, q), stigma (r),<br />
blue: liquid (c)<br />
white: ovules (o)<br />
yellow: stamens (l)
Violet Family (Violaceae)<br />
Members <strong>of</strong> this family are herbs and shrubs and usually<br />
perennial. Leaf-like appendages (stipules) occur<br />
at the base <strong>of</strong> simple, usually alternate leaves.<br />
Violet flowers are bisexual with flower parts in 5’s. The<br />
lowermost petal is <strong>of</strong>ten spurr<strong>ed</strong>. The flower’s pistil has<br />
a superior ovary <strong>of</strong> 3–5 fus<strong>ed</strong> carpels. The stamens,<br />
close around the pistil, are connect<strong>ed</strong> at the base and<br />
open inwardly. The fruit is a one-chamber<strong>ed</strong> capsule or<br />
a berry.<br />
Of interest...ornamental: Viola spp. (pansies, violets);<br />
essential oils: Viola oderata, grown for oil in the<br />
manufacture <strong>of</strong> perfumes, flavorings, and liqueur; food:<br />
Viola (leaves and flowers are <strong>ed</strong>ible, containing copious<br />
amounts <strong>of</strong> vitamins A and C) and crystalliz<strong>ed</strong> flowers<br />
are us<strong>ed</strong> for decoration; wild: Hybanthus (green violet),<br />
Rinorea, Viola spp. (violets).<br />
Viola papilionacea Common Blue Violet<br />
This perennial herb has a horizontal rhizome (a) and<br />
produces flowers in the spring and fertile cleistogamous<br />
flowers in the summer and fall. Cleistogamous<br />
flowers are small, lack petals, do not open, are selfpollinat<strong>ed</strong><br />
and occur near the base <strong>of</strong> the plant in soil<br />
substratum.<br />
92<br />
The leaf blades (b) have heart-shap<strong>ed</strong> bases with scallop<strong>ed</strong><br />
margins and are attach<strong>ed</strong> to long petioles (c) with<br />
stipules (d) at the bases.<br />
Flowers are borne on long p<strong>ed</strong>uncles (e) that arise from<br />
the base <strong>of</strong> the plant. The 5 sepals (f) have small projecting<br />
lobes (auricles, g). There are 5 unequal petals<br />
(h) with the 2 lateral petals beard<strong>ed</strong> with hairs (i) the<br />
base. The lower petal has a spur (j). (See bud drawing.)<br />
Purple nectar guides converge toward the base <strong>of</strong><br />
the white-throat<strong>ed</strong> petals.<br />
Five basally-fus<strong>ed</strong> stamens (k) enclose the ovary (l)<br />
(shown in a cross-section) and the style (m). The end<br />
<strong>of</strong> the style is enlarg<strong>ed</strong> and on the lower side is a beak,<br />
the stigma (n). Two <strong>of</strong> the stamens have nectar horns<br />
(o), which project into the lower petal spur (j). Pollen<br />
from the stamens sh<strong>ed</strong>s into the inner cone.<br />
As an insect probes for nectar, it moves the stigma<br />
aside and pollen in the cone sticks on its tongue. Crosspollination<br />
results when the next flower is visit<strong>ed</strong>.<br />
The pistil’s ovary (l) has 3 fus<strong>ed</strong> carpels with many<br />
ovules (p) in parietal placentation. At maturity, the fruit<br />
is a loculicidal capsule (q) with numerous se<strong>ed</strong>s (r).<br />
COLOR CODE<br />
white: rhizome (a), roots, stipules (d), beards<br />
(i) ovules (p)<br />
light green: petioles (c), p<strong>ed</strong>uncles (e), stamens (k),<br />
nectar horns (o), style (m), stigma (n)<br />
green: leaves (b), sepals (f, g)<br />
violet: petals (h), capsule (q)<br />
violet-brown: petal spur (j), ovary (l)<br />
dark brown: se<strong>ed</strong>s (r)
Begonia Family (Begoniaceae)<br />
This family <strong>of</strong> plants is native to the tropics and subtropics<br />
across the continents. It is popularly known for its<br />
Begonia cultivars grown as house plants. Plants in this<br />
family are perennial herbs or small shrubs. Most have<br />
succulent stems with alternate leaves and with deciduous<br />
stipules. Leaves are mostly palmately vein<strong>ed</strong> and<br />
usually asymmetrical with an oblique base.<br />
Unisexual male and female flowers occur on the same<br />
plant (monoecious). The male flower has 4 irregular<br />
tepals and many stamens in whorls. The pistil <strong>of</strong> the<br />
female flower has an inferior, angl<strong>ed</strong> or wing<strong>ed</strong> ovary<br />
consisting <strong>of</strong> usually 3 carpels and twist<strong>ed</strong> stigmas. Fruit<br />
types are a loculicidal capsule and a berry.<br />
Of interest...there are over 900 species within five<br />
genera: Begonia, Begoniella, Hillebrandia, Semibegoniella<br />
and Symbegonia; ornamental: Begonia (begonia)<br />
species are widely hybridiz<strong>ed</strong> in horticulture<br />
for flowering and foliage plants. Flowering plants are<br />
tuberous- and fibrous-root<strong>ed</strong>, such as B. semperflorens<br />
(wax begonia) and B. tuberhybrida (tuberous begonia).<br />
Foliage plants have rhizomes, such as B. rex (rex begonia)<br />
cultivars.<br />
Begonia semperflorens cultivar ‘Scarletta’<br />
This small plant flowers continuously (semperflorens<br />
= always flowering). Its waxy leaves (a, b) are<br />
93<br />
alternate and 2-rank<strong>ed</strong>, which means the leaves arise<br />
in one plane on opposite sides <strong>of</strong> the succulent stem<br />
(c). At the petiole (d) base is a pair <strong>of</strong> stipules (e). Veins<br />
(f) <strong>of</strong> the leaf blade radiate out from a common point<br />
(palmate venation). Wing<strong>ed</strong> capsules are also shown<br />
on the stem portion. The stalk (p<strong>ed</strong>uncle, g) supporting<br />
a cluster <strong>of</strong> flowers or capsules has bracts (h) where the<br />
flower stems (p<strong>ed</strong>icels, i)arise.<br />
A male flower has 2 petal-like sepals (j) and 2 smaller<br />
petals (k), together call<strong>ed</strong> tepals, and about 20-30 stamens<br />
(l). The stamen’s anther sacs (m) open (dehisce)<br />
longitudinally and have an enlarg<strong>ed</strong> connective (n) between<br />
them. There is a short filament.<br />
The four remaining drawings illustrate parts <strong>of</strong> the female<br />
flower. At the base <strong>of</strong> the flower are 3 bracts (p,<br />
x). Extending from the pistil’s inferior ovary are 3 unequal<br />
wings (q, v–w, z) partially cover<strong>ed</strong> by 5 tepals<br />
(r, y). The pistil’s 3 styles each have 2 twist<strong>ed</strong> stigmas<br />
(s, t).<br />
A cross-section <strong>of</strong> an ovary shows the 3 carpels (u) with<br />
numerous ovules. As the flower matures, pigments fade<br />
in the ovary wings (v, w) and bracts (x), and the tepals<br />
(y) wither. The capsules (z) have a papery texture and<br />
contain many se<strong>ed</strong>s.<br />
COLOR CODE<br />
dark green: upper blade surface (a)<br />
green: lower blade surface (b), stem (c)<br />
light green: petiole (d), p<strong>ed</strong>uncle (g), p<strong>ed</strong>icel (i),<br />
inner ovary wing (v)<br />
tan: stipules (e), bracts (h, x), tepals (y),<br />
capsule (z)<br />
r<strong>ed</strong>: tepals (j, k, r), bracts (p), ovary wings (q)<br />
yellow: stamens (l), anther sacs (m),<br />
connective (n), filament (o), stigma (s, t)<br />
white: carpels (u)<br />
r<strong>ed</strong>-brown: outer ovary wing (w)
Gourd Family (Cucurbitaceae)<br />
Plants in this family are mostly perennial herbaceous<br />
vines with spirally coil<strong>ed</strong> tendrils. Tendrils are modifi<strong>ed</strong><br />
stipules (see 23) that may be simple, fork<strong>ed</strong> or<br />
branch<strong>ed</strong>. Leaves are alternate, with usually palmate or<br />
pinnate venation. Plants lie flat (prostrate) and creep<br />
or climb (scandent). There are about 100 genera with<br />
over 700 species.<br />
Separate male and female (unisexual) flowers are most<br />
common in this family. This is a monoecious condition.<br />
Male flowers have unusual stamens. Where there may<br />
be 1-5, there are usually 3 stamens with one stamen<br />
having a one-chamber<strong>ed</strong> anther <strong>of</strong> 2 pollen sacs and<br />
2 stamens with 2-chamber<strong>ed</strong> anthers <strong>of</strong> 4 pollen sacs<br />
each.<br />
The female flower’s pistil has an inferior ovary consisting<br />
<strong>of</strong> 3-5 carpels, usually unit<strong>ed</strong> into a single chamber<br />
(locule) <strong>of</strong> ovules in parietal placentation.<br />
The fruit is a berry with a s<strong>of</strong>t fleshy pericarp or with<br />
a harden<strong>ed</strong> pericarp and classifi<strong>ed</strong> as a pepo. Before<br />
Linnaeus’ classification system, pepo was the name for<br />
pumpkin. Pepos that are dri<strong>ed</strong> for ornamental use or<br />
hollow vessels are commonly call<strong>ed</strong> gourds.<br />
Of interest...economically important as food:Citrullus<br />
lanatus (watermelon, citron), Cucumis anguiria (West<br />
Indian gerkin), C. melo (cantaloupe, honey-dew<br />
melon, melon), C. sativus (cucumber), Cucurbita spp.<br />
(pumpkins, squashes, vegetable marrows, vegetable<br />
spaghetti); ornamentals: gourds: Benincasa (Chinese<br />
94<br />
watermelon), Coccinea (ivy gourd), Lagenaria siceraria<br />
(calabash gourd, one <strong>of</strong> the earliest cultivat<strong>ed</strong> plants,<br />
dri<strong>ed</strong> to use as containers), Luffa cylindrica (lo<strong>of</strong>ah,<br />
dishcloth gourd, us<strong>ed</strong> as a dri<strong>ed</strong> sponge), Momordica<br />
(balsam apple), Sechium (chayote), Sicana (cassabanana),<br />
Sicyos (bur cucumber), Trichosanthes (snake<br />
gourd); T. kirilowii, the tree-<strong>of</strong>-joy from China, is an important<br />
anti-cancer plant containing the drug, trichosanthin.<br />
Cucumis sativus Cucumber<br />
The hairy stems (a) <strong>of</strong> this plant climb by means <strong>of</strong> tendrils<br />
(b) that arise at the petiole (c) bases. Five-lob<strong>ed</strong><br />
leaf blades (d) have palmate venation. Both male and<br />
female, unisexual flowers occur on the same plant (monoecious).<br />
A flower bud and a young female flower are<br />
on the shoot that is illustrat<strong>ed</strong>.<br />
Male flowers have 5 sepals, 5 petals (f), and 3 stamens<br />
(g). The stamens’ stout filaments (h) arise from<br />
the petals with the anthers join<strong>ed</strong> together in the center<br />
<strong>of</strong> the flower. The stamen illustrat<strong>ed</strong> has a 2-chamber<strong>ed</strong><br />
(bilocular) anther (i) with 4 pollen sacs (j).<br />
The female flower has 5 sepal lobes (k), 5 petals (l),<br />
and a single pistil. The pistil’s inferior ovary (m) consists<br />
<strong>of</strong> 3 unit<strong>ed</strong> carpels (n) with ovules (o) in parietal<br />
placentation. Glandular hairs (p) dot the ovary surface.<br />
Inside the fus<strong>ed</strong> sepal base (k) is a nectar disc (q). The<br />
style (r) emerges above and terminates in a 3-lob<strong>ed</strong><br />
stigma (s). After fertilization, the ovary develops into a<br />
pepo, the familiar cucumber fruit (see 39).<br />
COLOR CODE<br />
green: stem (a), petiole (c), leaf blade (d),<br />
p<strong>ed</strong>uncle (e), sepals (k), ovary (m)<br />
light green: tendril (b), filament (h), anther (i, j),<br />
glandular hairs (p), style (r), stigma (s)<br />
yellow: petals (f, l), stamens (g), disc (q)<br />
white: carpels (n), ovules (o)
Willow Family (Salicaceae)<br />
Plants in this family are woody trees or shrubs that<br />
are dioecious, producing male and female flowers on<br />
separate plants. Specializ<strong>ed</strong> and r<strong>ed</strong>uc<strong>ed</strong>, unisexual<br />
flowers are aggregat<strong>ed</strong> into catkins (aments). Leaves<br />
are alternate, simple, and deciduous with stipules and<br />
petioles.<br />
Familiar plants include the aspens, poplars and willows.<br />
There are four genera. In the North Temperate Zone are<br />
Populus with 300 species and Salix. In Northeast Asia,<br />
Chosenia and Toisusu occur.<br />
Populus flowers are wind-pollinat<strong>ed</strong>, while Salix flowers,<br />
with nectar glands, are insect-pollinat<strong>ed</strong>. The fruit<br />
is a 2-4-valv<strong>ed</strong> capsule with numerous, hairy (comose)<br />
se<strong>ed</strong>s.<br />
Of interest...ornamentals: Salix spp. (willows) with<br />
familiar species, S. babylonica (weeping willow), S.<br />
discolor (pussy-willow); Populus spp. (poplars, cottonwoods,<br />
aspens), P. grandidentata (large-tooth<strong>ed</strong><br />
aspen), P. deltoides (cottonwood), P. tremuloides (quaking<br />
aspen); pulpwood: Populus tremuloides (quaking<br />
aspen), P. balsamifers (balsam poplar); wickerware<br />
and basket-making: Salix (willow); aspirin: acetylsalicylic<br />
acid was originally deriv<strong>ed</strong> from the bark <strong>of</strong> Salix<br />
alba (white willow).<br />
Salix Willow<br />
The leaves (a) are alternate on the stem (b) and have<br />
tooth<strong>ed</strong> (dentate) margins. Flowers (c) <strong>of</strong> this male<br />
catkin have 3 stamens (d) with a hairy bract (e) and<br />
a nectar gland (f) below.<br />
The flowers (g) <strong>of</strong> the female catkin each have a single<br />
pistil with numerous ovules (h) in the ovary (i), a single<br />
style (j) and 2 stigmas (k). At the base <strong>of</strong> the flower<br />
p<strong>ed</strong>icel (l) is a bract (m) and a nectar gland (n). With the<br />
evolutionary r<strong>ed</strong>uction <strong>of</strong> parts, these specializ<strong>ed</strong> flowers<br />
consist <strong>of</strong> only stamens or a pistil and are without<br />
sepals and petals.<br />
During spring, the female catkin becomes a fuzzy mass<br />
<strong>of</strong> hairy (comose) se<strong>ed</strong>s (o) releas<strong>ed</strong> from 2-valv<strong>ed</strong> (p)<br />
capsules to be dispers<strong>ed</strong> by wind.<br />
95<br />
COLOR CODE<br />
green: leaf (a), female catkin flowers (g),<br />
p<strong>ed</strong>icel (l)<br />
brown: stem (b), capsule valves (p)<br />
yellow: male flowers (c), stamens (d)<br />
dark brown: bracts (e, m)<br />
light green: nectaries (f, n), ovules (h), ovary (i),<br />
style (j), stigmas (k)<br />
tan: se<strong>ed</strong> (o)
Mustard Family (Brassicaceae)<br />
The old family name, Cruciferae, refers to the cross form<br />
(cruciform) <strong>of</strong> the 4 diagonally oppos<strong>ed</strong> petals. Flowers<br />
also have 4 sepals. Stamen number and lengths and<br />
the single pistil’s ovary with a false partition are notable<br />
characteristics found in this family (the illustrat<strong>ed</strong> plant<br />
shows these features). The specializ<strong>ed</strong> type <strong>of</strong> fruit produc<strong>ed</strong><br />
from the ovary is a narrow silique or a round<br />
silicle, in which se<strong>ed</strong>s are separat<strong>ed</strong> into 2 chambers<br />
by a partition and cover<strong>ed</strong> on each side by a valve (see<br />
dry fruit types, silique, 38).<br />
This family consists <strong>of</strong> annual, biennial, or perennial<br />
herbs with pungent oils in the sap. There are about 380<br />
genera and about 3,000 species. The leaves are alternate<br />
and simple and usually have fork<strong>ed</strong> or star-like,<br />
one-cell<strong>ed</strong> hairs.<br />
Of interest...food: Armoracia rusticana (horseradish);<br />
Brassica nigra (mustard); Brassica napus<br />
(rape, rapese<strong>ed</strong> oil, canola oil); Brassica oleracea<br />
(wild cabbage, colewort) select<strong>ed</strong> varieties produc<strong>ed</strong><br />
such cole crops as B. capitate (head <strong>of</strong><br />
leaves—cabbage), B. acephala (without a head—<br />
kale), B. botrytis (cluster <strong>of</strong> white flower buds—<br />
cauliflower), B. gemmifera (axillary buds—Brussels<br />
sprouts), B. italica (green flower buds—broccoli),<br />
B. caulorapa (swollen stem—kohlrabi), B. napobrassica<br />
(rutabaga); Eruca sativa (arugula); Nasturtium<br />
<strong>of</strong>ficinale (water cress); Raphanus sativus (radish);<br />
we<strong>ed</strong>s: Alliaria petiolata (garlic mustard); Brassica<br />
spp. (wild mustards), Capsella bursapastoris (shepherd’s<br />
purse), Lepidium densiflorum (pepper-grass),<br />
Draba (hoary cress), Thlaspi arvensis (penny cress);<br />
ornamentals: Arabis caucasica (rock cress), Aubrieta<br />
(false rockcress), Erysimum (wallflower), Hesperis<br />
matronalis (rocket), Iberis sempervirens (candytuft),<br />
Lobularia maritima (sweet alyssum), Lunaria annua<br />
96<br />
(honesty, money plant), Matthiola (stock); dye: Isatis<br />
tinctoria (dyer’s woad); endanger<strong>ed</strong>: Cardamine diphylla<br />
(two-leav<strong>ed</strong> toothwort), C. dissecta (divid<strong>ed</strong><br />
toothwort).<br />
Alliaria petiolata (garlic mustard) is the scourge <strong>of</strong> the<br />
forest, replacing native wildflowers by shading them out<br />
<strong>of</strong> existence. As a biennial, it produces a rosette <strong>of</strong><br />
leaves the first year, and flowers and se<strong>ed</strong>s the second<br />
year, then dies. One plant can produce several thousand<br />
se<strong>ed</strong>s that are viable for seven years or more.<br />
Garlic mustard eliminates native food plants for native<br />
animals. In state parks overrun with garlic mustard, it<br />
is not unusual to see deer begging for <strong>ed</strong>ible handouts<br />
from tourists.<br />
Lobularia maritima Sweet Alyssum<br />
A native <strong>of</strong> the M<strong>ed</strong>iterranean area, this plant is an annual<br />
or perennial herb. The leaves (a) are linear and<br />
alternate to almost opposite on the stem (b). The habit<br />
drawing shows the p<strong>ed</strong>icell<strong>ed</strong> flowers (c), borne on a<br />
stalk (raceme) and the silicle (d) fruit.<br />
The p<strong>ed</strong>icel (e) supports a flower with 4 hairy<br />
sepals (f) that alternate with the 4, diagonally oppos<strong>ed</strong><br />
petals (g). The 6 stamens are tetradynamous, which<br />
means there are 4 long stamens (h) and 2 outer short<br />
stamens (i). At the base <strong>of</strong> the filament are nectaries<br />
(j), seen when the sepals and petals are remov<strong>ed</strong>.<br />
The single pistil has a superior ovary (k) and a capitate<br />
stigma (l). When the silicle fruit develops. the ovary’s<br />
false partition (replum, m) can be seen separating the<br />
se<strong>ed</strong>s (n). Two outer valves (o) are sh<strong>ed</strong> to release the<br />
se<strong>ed</strong>s.<br />
COLOR CODE<br />
green: leaves (a), stem (b), p<strong>ed</strong>icel (e),<br />
sepals (f)<br />
white or lavender: flowers (c), petals(g)<br />
yellow: silicle (d), stamens (h, i), replum<br />
(m), valves (o)<br />
pale green: nectaries (j), ovary (k), stigma (l)<br />
tan: se<strong>ed</strong>s (n)
Heath Family (Ericaceae)<br />
Shrubs are the most common in this family, but some<br />
plants are perennial herbs, trees, or vines. Most prefer<br />
acidic substrate and many have fungus-root (mycorrhizal)<br />
associations (see 12). Leaves are simple, alternate,<br />
sometimes opposite or whorl<strong>ed</strong>, and <strong>of</strong>ten leathery<br />
and evergreen. There are about 100 genera and<br />
about 3,000 species.<br />
Flowers are bisexual, borne, singly or in clusters. The<br />
4-5 sepals are distinct or join<strong>ed</strong> at the base. There are<br />
usually 4-5 petals join<strong>ed</strong> in a funnel or urn-shape, but in<br />
some genera, the petals are separate. Stamens are the<br />
same or twice the number <strong>of</strong> petals. The single pistil has<br />
a superior ovary <strong>of</strong> 4-10 carpels with ovules usually in<br />
axile placentation, and a single style and stigma. Fruit<br />
types (see 38, 39) include capsules, berries, or drupes.<br />
Of interest...food: Gaultheria procumbens (oil-<strong>of</strong>wintergreen),<br />
Gaylussacia (huckleberry), Vaccinium<br />
spp. (bilberry, blueberry, cranberry, lingonberry); ornamentals:<br />
Calluna (heather), Enkianthus campanulatus<br />
(r<strong>ed</strong>vein enkianthus), Kalmia latifolia (mountain<br />
laurel), Leucothoe catesbii (leatherleaf), Oxydendrum<br />
arboreum (sourwood), Pieris japonica (androm<strong>ed</strong>a),<br />
Rhododendron spp. (rhododendron, azalea); wild:<br />
Arctostaphylos (bearberry), Epigaea repens (trailing<br />
arbutus); poisonous: Androm<strong>ed</strong>a glaucophylla (bog<br />
rosemary), Kalmia angustifolia (lamb-kill), K. latifolia<br />
(mountain laurel), K. polifolia (swamp laurel), Leucothoe<br />
spp., Lyonia mariana (stagger-bush), Menziesia ferruginea<br />
(fool’s huckleberry), Rhododendron spp. It is advis<strong>ed</strong><br />
not to roast food on sticks <strong>of</strong> any <strong>of</strong> the plants<br />
list<strong>ed</strong>.<br />
Here is how to tell a rhododendron from an azalea.<br />
Although they share the same genus (Rhododendron),<br />
97<br />
rhododendron flowers have 10 stamens while azalea<br />
flowers have 5 stamens. Rhododendrons are<br />
mostly evergreen plants, while azaleas are mostly<br />
deciduous.<br />
Arctostaphylos uva-ursi Bearberry, Kinnikinik<br />
This plant forms mats <strong>of</strong> prostrate shrubs, clon<strong>ed</strong> by<br />
shoots arising from the root system. The alternate leathery<br />
leaves (a) are evergreen. Young stems (b) and<br />
leaf blade margins and petioles are cover<strong>ed</strong> with fine<br />
hairs.<br />
Urn-shap<strong>ed</strong> flowers are borne in small clusters at the<br />
end <strong>of</strong> the shoot. The flower has 5 basally fus<strong>ed</strong>, pink<br />
sepals (c), a fus<strong>ed</strong> petal tube (d) with 5 lobes (e),<br />
10 stamens, and a single pistil with a superior ovary.<br />
The stamen’s anther (f) has 2 cells each with a pore<br />
(g) for pollen dispersal and a bristly awn (h) at the<br />
base <strong>of</strong> each. The stamen’s filament (i) is dilat<strong>ed</strong> at the<br />
base.<br />
The pistil’s ovary (j) has 5-8 chambers (locules) with<br />
one ovule (k) in each, in axile placentation. The pistil<br />
has a single columnar style (l) and stigma (m). The<br />
ovary is elevat<strong>ed</strong> on a 2-lob<strong>ed</strong> nectar disc (n). Hairs (o)<br />
line the inner surface <strong>of</strong> the petal tube and cover the<br />
stamen’s dilat<strong>ed</strong> filament base.<br />
As the drupe (r) type fruit matures, the skin color<br />
changes from yellow to r<strong>ed</strong>, then to purple as it decays.<br />
Inside is a fleshy mesocarp (s) surrounding<br />
the fus<strong>ed</strong> nutlets (t). Yellow veins (u) run as a band<br />
along the back <strong>of</strong> each and as seams between the<br />
nutlets.<br />
COLOR CODE<br />
green: leaves (a), disc (n)<br />
brown: stem (b)<br />
dark pink: sepals (c), petal lobes (e)<br />
pale yellow: petal tube (d), mesocarp (s), vein (u)<br />
purple: anther (f)<br />
pink: awn (h)<br />
r<strong>ed</strong>-brown: p<strong>ed</strong>icel (p), bract (q)<br />
r<strong>ed</strong>: drupe (r)<br />
tan: nutlet (t)<br />
white: filament (i), ovary (j), ovule (k),<br />
style (l), stigma (m)
Saxifrage Family (Saxifragaceae)<br />
Distinctive characteristics to identify this family are<br />
lacking. The flower parts tend to be in 4’s or 5’s with<br />
stamens one or two times the number <strong>of</strong> sepals and<br />
with a pistil consisting <strong>of</strong> 2-5 unit<strong>ed</strong> carpels having numerous<br />
ovules.<br />
The leaves are mostly without stipules and usually alternate<br />
on these commonly perennial herbs and deciduous<br />
shrubs. The fruit type is a capsule or berry.<br />
Of interest...food: Ribes spp. (gooseberry, currant);<br />
ornamentals: Astilbe (false goat’s-beard),<br />
Bergenia cordifolia (pigsqueak), Darmera, Deutzia,<br />
× Heucherella (Heuchera × Tiarella), Heuchera (coral<br />
bells), Hydrangea, Mukdenia, Philadelphus (mock orange),<br />
Rodgersia (Roger’s flower), Saxifraga spp.<br />
(saxifrages), S. stolonifera (see 16, strawberry begonia,<br />
Aaron’s-beard, mother-<strong>of</strong>-thousands); wild: Mitella<br />
(bishop’s-cap), Tiarella (foamflower, false miterwort).<br />
Ribes americanum Wild Black Currant<br />
This shrub has alternate leaves (a) with yellow resin<br />
dots (b) on the lower surface <strong>of</strong> the blades.<br />
Small flowers (d) have 5 petal-like sepals (e), 5 petals<br />
(f), and 5 stamens (g). The single pistil has an inferior<br />
ovary (h) <strong>of</strong> 2 unit<strong>ed</strong> carpels with ovules (i) in parietal<br />
placentation, and a style (j) that divides into 2 stigmas<br />
(k).<br />
Heuchera sanguinea Coral Bells<br />
This perennial herb has basal leaves (m) and develops<br />
flowering shoots on long p<strong>ed</strong>uncles (n). The p<strong>ed</strong>uncle<br />
is green at the base and fades into dark pink at the<br />
top where the flowers occur. Like Ribes, the 5 sepals<br />
(p) are unit<strong>ed</strong> at the base and petal-like. With magnification,<br />
delicate, pink, glandular hairs can be seen on<br />
the sepals. Inside the sepal tube are 5 tiny petals (q),<br />
5 stamens (r) and a pistil with 2 stigmas.<br />
Philadelphus Mock Orange<br />
This deciduous shrub has opposite leaves and flowers<br />
that have the fragrance <strong>of</strong> orange blossoms and produce<br />
loculicidal capsules (s).<br />
98<br />
COLOR CODE<br />
yellow: resin dots (b), stamens (g, r)<br />
green: leaves (a, c, m) p<strong>ed</strong>icel (l), p<strong>ed</strong>uncle (n)<br />
pale yellow: flowers (d), sepals (e), petals (f)<br />
white: ovary (h), ovules (i), style (j), stigmas (k)<br />
pale pink: petals (q), upper portion <strong>of</strong> p<strong>ed</strong>uncle (n)<br />
dark pink: p<strong>ed</strong>icel (o), sepals (p)<br />
tan: capsule (s), stem (t)
Rose Family (Rosaceae)<br />
Common features in this family include the following:<br />
leaf stipules are usually present, flower parts are in 5’s<br />
and the flower has a cup-like receptacle or floral tube,<br />
call<strong>ed</strong> a hypanthium, which develops around the ovary.<br />
Plants in the rose family range from herbs and shrubs<br />
to trees. Many have spines and a few are climbers. Usually,<br />
the leaves are alternate, simple or compound, with<br />
tooth<strong>ed</strong> (dentate) margins. The flower is usually bisexual<br />
and has an enlarg<strong>ed</strong> nectar cup that inflates the floral<br />
tube, has stamens in whorls <strong>of</strong> five, and possesses<br />
a single compound pistil or many pistils together.<br />
There are over 3,000 species in the Rose Family.<br />
Of interest...fruit types: achene, drupe, follicle and<br />
pome. Rose family plants have English common names<br />
for the <strong>ed</strong>ible fruits. In combination with the fruit<br />
type, some examples follow. Strawberry (Fragaria) is<br />
an aggregate <strong>of</strong> achenes. Pear (Pryus), apple (Malus),<br />
and quince (Cydonia) are pomes. Cherry (Prunus<br />
avium), peach (Prunus persica), plum (Prunus spp.)<br />
and apricot (Prunus armeniaca) are drupes. Blackberry<br />
(Rubus ulmifolius), raspberry (Prunus idaeus), loganberry<br />
(Prunus loganobaccus), dewberry (Rubus caesius)<br />
and cloudberry (Rubus chamaemorus) are aggregates<br />
<strong>of</strong> drupelets. The fleshy fruit <strong>of</strong> the almond<br />
(Prunus dulcis) is not eaten; the common name represents<br />
the se<strong>ed</strong> inside the drupe’s pit, while a similar<br />
appearing se<strong>ed</strong> in the peach drupe contains a poison,<br />
cyanide, as do the pome se<strong>ed</strong>s <strong>of</strong> apple (Malus).<br />
Ornamental shrubs whose fruits are not usually eaten<br />
are nam<strong>ed</strong> for other characteristics. Nam<strong>ed</strong> for thorns,<br />
hawthorn (Crataegus) and firethorn (Pyracantha) have<br />
pome fruits. Bridal wreath (Spiraea) is cultivat<strong>ed</strong> for<br />
its sprays <strong>of</strong> white flowers and has a follicle fruit, as<br />
does ninebark (Physocarpus). Mountain ash (Sorbus),<br />
with a pome fruit, has compound leaves similar to<br />
those <strong>of</strong> ash (Fraxinus) in the olive family. Roses (Rosa<br />
spp.) are cultivat<strong>ed</strong> for their showy flowers, which are<br />
<strong>ed</strong>ible (candi<strong>ed</strong> rose buds) and develop into “hips”<br />
compos<strong>ed</strong> <strong>of</strong> many carpels, which form an aggregate<br />
<strong>of</strong> achenes high in vitamin C. Other ornamental<br />
shrubs are Amelanchier (with many common names:<br />
Juneberry, serviceberry, shadblow, shadbush), Aronia<br />
(chokeberry), and Kerria japonica from China. Some<br />
99<br />
ornamental herbaceous perennials include lady’s<br />
mantle (Alchemilla), goatsbeard (Aruncus), meadowsweet<br />
(Filipendula), avens (Geum), cinquefoil (Potentilla),<br />
and burnet (Sanguisorba).<br />
Malus pumila Apple<br />
This is a tree <strong>of</strong> spreading branches. The stems (a) have<br />
characteristic short, spur shoots (b) that bear leaves,<br />
flowers, and fruits. Small stipules (d) occur at the petiole<br />
base.<br />
The flower has 5 basally join<strong>ed</strong> sepals (e) and 5 petals,<br />
which are white above and pink below (f). In bud (g), the<br />
flowers appear pink. When the flower opens, the petals<br />
appear white and are blush<strong>ed</strong> pink from the recurv<strong>ed</strong><br />
tips. There are many stamens (h) in whorls <strong>of</strong> 5.<br />
The vertical section shows the stamens (j) attach<strong>ed</strong> to<br />
the floral tube (k) outside the nectar cup (l). The pistil<br />
has an inferior ovary (m) with 5 carpels (n) and a style<br />
(o) that projects through the nectar cup and divides into<br />
5 branches topp<strong>ed</strong> with stigmas (p).<br />
The cross-section <strong>of</strong> an ovary shows the floral tube<br />
tissue (k), carpellary tissue (q) and ovules (r) in the<br />
5 carpels. Other features are vascular bundles <strong>of</strong> the<br />
carpels (s), petals (t), and sepals (u). A hairy epidermis<br />
(v) covers the floral tube.<br />
The cross and vertical sections <strong>of</strong> a pome show how<br />
the structures <strong>of</strong> a small flower develop into a fruit<br />
after fertilization. The ovules develop into se<strong>ed</strong>s (w) in<br />
the carpels (n). Carpellary tissue (q) enlarges, the floral<br />
tube tissue (k) expands, and the epidermis (x) becomes<br />
pigment<strong>ed</strong> (yellow, r<strong>ed</strong>, or green).<br />
COLOR CODE<br />
brown: stem (a), short shoot (b), se<strong>ed</strong>s (w)<br />
green: leaves (c), stipules (d), sepals (e),<br />
p<strong>ed</strong>uncle (i), sepal bundles (u),<br />
epidermis (v)<br />
pink: lower surface <strong>of</strong> petals (f), bud (g)<br />
yellow: stamens (h, j)<br />
white: floral tube tissue (k), nectar cup (l),<br />
carpels (n)<br />
light green: stigmas (p), petal bundles (t)<br />
r<strong>ed</strong>: epidermis (x)<br />
pale yellow: carpellary tissue (q), ovules (r), carpel<br />
bundles (s)
Pea Family (Fabaceae)<br />
The old family name was Leguminosae, a reference to<br />
the legume fruit (see 38). Members <strong>of</strong> this family are<br />
easily recogniz<strong>ed</strong> by the usually alternate, compound<br />
leaves divid<strong>ed</strong> into leaflets, the typical pea flower, and<br />
the pea pod (legume) fruit. The form <strong>of</strong> plants ranges<br />
from small herbs to shrubs and trees. There are 700<br />
genera and over 17,000 species.<br />
Looking closely at the leaves, the base <strong>of</strong> each has a<br />
pair <strong>of</strong> leaf-like stipules. The leaf petiole has a swollen<br />
base (pulvinus) that has the ability to change the<br />
position <strong>of</strong> the leaf and leaflets when stimulat<strong>ed</strong> by<br />
light or gravity. When touch<strong>ed</strong>, Mimosa, the sensitive<br />
plant, demonstrates this ability, dramatically (movement<br />
occurs rapidly).<br />
A pea flower has 5 fus<strong>ed</strong> sepals, with 5 separate petals<br />
or petals in 3 groups <strong>of</strong> one banner petal, two wing<br />
petals, and a keel <strong>of</strong> 2 fus<strong>ed</strong> petals that enclose the<br />
stamens after fertilization. The ovules are attach<strong>ed</strong> to<br />
the side <strong>of</strong> the carpel wall in two alternating rows.<br />
Some species have only two se<strong>ed</strong>s per legume pod;<br />
others may have many. Pods may be straight such as<br />
in garden beans and peas, or straight and section<strong>ed</strong><br />
into compartments call<strong>ed</strong> a loment, or coil<strong>ed</strong> in a spiral<br />
(see 38). When mature, the pod splits into halves.<br />
Pea family plants such as clover or alfalfa are <strong>of</strong>ten us<strong>ed</strong><br />
in crop rotation because they increase soil nitrogen, a<br />
plant nutrient, by the presence <strong>of</strong> bacterial nitrogenfixing<br />
nodules on the roots (see 12).<br />
Of interest...economically important for food: Arachis<br />
(peanut), Cicer (chick pea), Glycine max (soybean),<br />
Lens (lentil), swollen roots <strong>of</strong> Pachyrhizus erosus<br />
(jicama), Phaseolus spp. (beans), Pisum (pea),<br />
Tamarindus (tamarind), Vicia faba (broad bean, fava<br />
bean), Vigna angularis (adzuki bean); native American<br />
foods: tubers <strong>of</strong> Apios americana (ground nut),<br />
tubers <strong>of</strong> Psoralea esculenta (prairie potato); fodder:<br />
Lupinus (lupine), M<strong>ed</strong>icago (alfalfa), Melilotus (sweet<br />
clover), Prosopsis juliflora (Mexican mesquite tree pods<br />
and beans), Trifolium (clover, see 33), Vicia (vetch); ornamentals:<br />
Acacia (wattle), Albizzia, Baptisia (false indigo),<br />
Bauhinia (orchid tree), Caesalpinia pulcherrima<br />
(pride <strong>of</strong> Barbados), Cassis (senna), Cercis (r<strong>ed</strong>bud),<br />
Cytisus scoparius (Scotch broom), Delonix (poinciana),<br />
Genista, Gl<strong>ed</strong>itsia (honey locust), Laburnum (goldenchain<br />
tree), Lathyrus (sweet pea), Lupinus (lupine),<br />
100<br />
Mimosa (sensitive plant), Wisteria (wisteria); dye<br />
plants: Genista tinctoria (yellow dye), Indig<strong>of</strong>era (indigo);<br />
poisonous: Abrus precatorius (precatory bean),<br />
Astragalus (locowe<strong>ed</strong>), Gymnocladus (Kentucky c<strong>of</strong>fee<br />
tree), Lupinus argenteus (silvery lupine), Robinia (locust);<br />
invasive we<strong>ed</strong>s: introduc<strong>ed</strong> to the Unit<strong>ed</strong> States<br />
for erosion control, Coronilla varia (crown vetch) is now<br />
an invasive plant overrunning natural prairies and savannas;<br />
Pueraria montana (kudzu vine, “the vine that<br />
ate the south.”)<br />
Lathyrus latifolius Sweet Pea<br />
A perennial herb, the sweet pea plant climbs by means<br />
<strong>of</strong> tendrils (a) on its broadly wing<strong>ed</strong> stems (b). Doublelob<strong>ed</strong><br />
stipules (c) emerge from nodes on the stem. The<br />
compound leaf has a wing<strong>ed</strong> petiole (d) and two leaflets<br />
(e).<br />
The raceme inflorescence has a long p<strong>ed</strong>uncle (f) that<br />
supports many flowers on short p<strong>ed</strong>icels (g). In addition<br />
to a sepal tube (h) with 5 lobes, the flower has a corolla<br />
divid<strong>ed</strong> into a banner petal (i), 2 wing petals (j), and a<br />
keel (k) compos<strong>ed</strong> <strong>of</strong> 2 fus<strong>ed</strong> petals. Petal color varies<br />
from white to pink to dark pink-r<strong>ed</strong>.<br />
With the petals remov<strong>ed</strong> from a flower bud, 10<br />
2-chamber<strong>ed</strong> stamens (l) enclose the pistil in 2 bundles<br />
<strong>of</strong> one above plus nine basally fus<strong>ed</strong> ones. A<br />
flower, with sepals (h) also remov<strong>ed</strong>, and ovary (m), cut<br />
open, shows the ovules (n) attach<strong>ed</strong> to the inner carpel<br />
wall. Extending from the ovary are the style (o) and<br />
stigma (p).<br />
When the sweet pea legume (q) matures, the carpel<br />
wall splits into two halves and twists, thus expelling the<br />
se<strong>ed</strong>s(r).<br />
COLOR CODE<br />
green: tendril (a), stem (b), stipules (c),<br />
petiole (d), leaflets (e), p<strong>ed</strong>uncle (f),<br />
p<strong>ed</strong>icel (g), sepals (h)<br />
white, pink, or<br />
pink-r<strong>ed</strong>: petals (i, j, k)<br />
yellow: stamens (l)<br />
light green: ovary (m), ovules (n), style (o),<br />
stigma (p)<br />
tan: legume (q)<br />
dark brown: se<strong>ed</strong>s (r)
Dogwood Family (Cornaceae)<br />
Plants in this family are usually woody trees and shrubs<br />
with simple, usually opposite leaves. The small flowers<br />
are arrang<strong>ed</strong> in clusters that are sometimes subtend<strong>ed</strong><br />
by bracts that may be quite showy. The flower is bisexual<br />
or has unisexual male and female flowers on one<br />
plant (monoecious) or on separate plants (dioecious).<br />
There are about 13 genera and over 100 species.<br />
Attach<strong>ed</strong> to the ovary are 4–5 sepals and 4–5 petals<br />
or none. The number <strong>of</strong> stamens is the same as the<br />
number <strong>of</strong> petals. There is a single pistil with an inferior<br />
ovary consisting <strong>of</strong> 2–4 carpels. A glandular disc<br />
surrounds the one or more styles. Fruits are drupes or<br />
berries.<br />
Of interest...ornamentals: Acuba (Japanese laurel),<br />
Cornus canadensis (bunchberry), C. florida (flowering<br />
dogwood), C. sericea (r<strong>ed</strong>-osier dogwood), C. mas<br />
(Cornelian cherry), C. kousa (Japanese dogwood),<br />
C. racemosa (grey dogwood), Griselinia spp. (kapuka),<br />
Helwingia.<br />
Cornus florida variety rubra<br />
Flowering Dogwood<br />
This small tree has widely spreading branches and is<br />
valu<strong>ed</strong> as an ornamental specimen tree in landscaping.<br />
In nature, this understory tree <strong>of</strong> the forest has white<br />
flowers. Mutant pink and r<strong>ed</strong> varieties have been select<strong>ed</strong><br />
from natural populations <strong>of</strong> flowering dogwood<br />
and propagat<strong>ed</strong> for horticultural use.<br />
The opposite leaves are simple with entire, wavy margins.<br />
In autumn they turn a deep r<strong>ed</strong> color.<br />
What appear to be pink flower petals are actually 4 large<br />
bracts (b) around a cluster <strong>of</strong> 20-30 bisexual flowers (c)<br />
with yellow petals. Each flower has 4 join<strong>ed</strong> sepals (d),<br />
4 small petals (e, f), 4 stamens (g), and a single pistil<br />
(h). The stamens arise from the base <strong>of</strong> a nectar disc<br />
(k). Parts <strong>of</strong> the pistil include a 2-carpell<strong>ed</strong> ovary (l) with<br />
an ovule (m) in each locule, a style (n), and stigma (o).<br />
Birds are very fond <strong>of</strong> the bright r<strong>ed</strong> drupe fruits (p).<br />
101<br />
COLOR CODE<br />
dark pink: bract veins (a)<br />
pink: bracts (b)<br />
yellow-green: flowers (c), bud petals (e)<br />
light green-pink: sepals (d)<br />
white: filament (j), ovary (l), ovules (m)<br />
yellow: petals (f), stamens (g), anther (i),<br />
nectar disc (k)<br />
light green: pistil (h), style (n), stigma (o)<br />
r<strong>ed</strong>: drupes (p)<br />
gray: p<strong>ed</strong>uncle (q)<br />
optional: leaf (green in summer; or dark r<strong>ed</strong><br />
with yellow veins in autumn)
Staff-tree Family (Celastraceae)<br />
The most obvious characteristic this family is the pulpy<br />
orange or r<strong>ed</strong> aril usually covering the se<strong>ed</strong>. Small clusters<br />
<strong>of</strong> green flowers usually have flower parts in 4’s<br />
or 5’s. The flowers are bisexual or sometimes polygamodioecious<br />
(see Celastrus, below). There is one<br />
pistil with a superior ovary surround<strong>ed</strong> by a nectar disc.<br />
Plants in this family are woody shrubs, trees, and twining<br />
vines. Leaves are simple, alternate or opposite.<br />
There are 55 genera and 850 species.<br />
Of interest...ornamentals: Catha (Cafta), Celastrus<br />
(bittersweet), Elaeodendron, Euonymus alatus<br />
(burning bush), Gymnosporia, Maytenus, Pachystima,<br />
Tripterygium; furniture making: Euonymus europaeus<br />
(European spindle tree); food: Catha <strong>ed</strong>ulis (Khat tree),<br />
leaves for tea.<br />
Euonymus alatus Burning Bush,<br />
Wing<strong>ed</strong> Wahoo<br />
This shrub’s stems (a) have a wing<strong>ed</strong> appearance because<br />
<strong>of</strong> the presence <strong>of</strong> corky ridges (b) <strong>of</strong> periderm.<br />
Its opposite leaves (c) have finely tooth<strong>ed</strong> (dentate)<br />
margins and hair-like stipules (d) at the base <strong>of</strong> the petioles.<br />
In autumn, the leaves are a brilliant r<strong>ed</strong>.<br />
The flowers are borne in a cluster, with the central<br />
flower opening first (cyme). Parts <strong>of</strong> the bisexual flower<br />
consist <strong>of</strong> 4 sepals (e), 4 petals (f), and 4 stamens<br />
(g) surrounding the single pistil (h) with 4 carpels (i).<br />
102<br />
Stamens and pistil are situat<strong>ed</strong> on a disc (j), which is<br />
a fleshy receptacle with the sepals and petals arising<br />
around it.<br />
After the leaves are sh<strong>ed</strong> in autumn, the loculicidal<br />
capsule (m) is more obvious. A r<strong>ed</strong> outer covering (aril,<br />
n) encloses the se<strong>ed</strong>s.<br />
This vigorous growing native <strong>of</strong> the Temperate Zone in<br />
East Asia can crowd out plants that are native to the<br />
American Temperate Zone because <strong>of</strong> its prodigious<br />
se<strong>ed</strong> production and high se<strong>ed</strong>ling survival rate.<br />
Celastrus scandens Bittersweet<br />
Bittersweet is a twining vine with alternate leaves (o).<br />
Polygamodioecious is the condition describing the<br />
plants’ flowers. This means that unisexual male and female<br />
flowers are mainly on separate plants, but bisexual<br />
flowers are also present on both plants.<br />
The male flower consists <strong>of</strong> 5 sepals (r), 5 petals (s), 5<br />
stamens (t), and a vestigial pistil (u). The female flower<br />
(not shown) has a pistil compos<strong>ed</strong> <strong>of</strong> 3 carpels, a single<br />
style, and a 3-lob<strong>ed</strong> stigma with vestigial stamens<br />
present.<br />
The fruit type is a loculicidal capsule. Three orange<br />
valves (v) open to expose a r<strong>ed</strong> aril (w) covering the<br />
se<strong>ed</strong>s. Autumn branches <strong>of</strong> orange fruits are us<strong>ed</strong> for<br />
decoration.<br />
COLOR CODE<br />
brown: bark ridges (b)<br />
green: stem (a, p), leaves (c, o), stamens (g),<br />
pistil (h), carpels (i), p<strong>ed</strong>icel (k, q),<br />
disc (j), p<strong>ed</strong>icel (k, q),<br />
light green: sepals (e, r), petals (s)<br />
yellow-green: petals (f)<br />
pink: p<strong>ed</strong>icel (l)<br />
lavender: capsules’ valves (m)<br />
orange: capsules’ valves (v)<br />
r<strong>ed</strong>: arils (n, w)<br />
yellow: p<strong>ed</strong>icel (x), stamens (t)<br />
white: pistil (u)
Spurge Family (Euphorbiaceae)<br />
Euphorbs, a large family <strong>of</strong> 283 genera, <strong>of</strong>ten have<br />
a poisonous, milky, latex sap. Very diverse forms are<br />
represent<strong>ed</strong>. There are we<strong>ed</strong>y herbs, commonly call<strong>ed</strong><br />
spurges, showy ornamental herbs, trees, and cactuslike<br />
succulents. Most are tropical. Stems usually have<br />
stipules that take the form <strong>of</strong> hairs, glands, or spines.<br />
False flowers, <strong>of</strong>ten with petal-like appendages, have<br />
unisexual, male and female flowers aggregat<strong>ed</strong> in a<br />
cyanthium (a cup-like structure). Male flowers, <strong>of</strong> one<br />
stamen each, may number 1 to many in a cyanthium.<br />
The female flower is a single pistil compos<strong>ed</strong> <strong>of</strong> a superior<br />
ovary with usually 3 fus<strong>ed</strong> carpels, 3 styles, and<br />
3-6 stigmas. The fruit is usually a schizocarp in which<br />
the three carpels, bearing se<strong>ed</strong>s, break apart.<br />
Of interest...economic: Aleurites fordii (tung oil, us<strong>ed</strong><br />
in paints and quick-drying varnishes), Hevea brasiliensis<br />
(para rubber, the most important source <strong>of</strong> natural<br />
rubber), Manihot esculenta (tapioca, bitter cassava,<br />
manioc, sweet-potato tree; the starchy roots<br />
yield many food products), M. glaziovii (ceara rubber),<br />
Ricinus communis (castor oil); ornamentals: Acalpha<br />
hispida (chenille plant), Codiaeum (croton), Euphorbia<br />
with 1550 species (poinsettia, crown-<strong>of</strong>-thorns,<br />
spurges), P<strong>ed</strong>ilanthus tithymaloides (r<strong>ed</strong>bird flower,<br />
slipper flower, r<strong>ed</strong>bird cactus, Japanese poinsettia),<br />
Phyllanthus (Otaheite gooseberry, gooseberry tree),<br />
Ricinus communis (castor-bean).<br />
poisonous: Aleurites fordii (tung oil), Euphorbia spp.,<br />
The milky sap <strong>of</strong> Euphorbia species causes dermatitis<br />
with severe blistering on contact with human skin,<br />
103<br />
E. marginata (snow-on-the-mountain, ghostwe<strong>ed</strong>), a<br />
garden ornamental, is especially corrosive to the skin;<br />
Ricinus communis (castor-bean, castor-oil-plant) contains<br />
ricin, a blood poison. All parts <strong>of</strong> the plant are poisonous,<br />
but particularly the “bean” (se<strong>ed</strong>s). If ingest<strong>ed</strong><br />
severe poisoning, ending in convulsions and death, can<br />
occur.<br />
Euphorbia milii Crown-<strong>of</strong>-thorns<br />
This native <strong>of</strong> Madagascar is a spiny, succulent<br />
shrub. The stem (a) has alternate, simple leaves (b),<br />
spiny stipules (c), and latex sap (d). Two flowering<br />
shoots (e) are shown, one with the petal-like appendages<br />
(f) in bud and the other with the appendages<br />
expand<strong>ed</strong> (g).<br />
The drawing shows an enlarg<strong>ed</strong> false flower, call<strong>ed</strong> a<br />
pseudanthium, has five nectar glands (h) and 5 bracts<br />
(i) that surround the flowers. At the center <strong>of</strong> each <strong>of</strong><br />
the female flowers are 3 styles (j), which divide into 2<br />
stigmas (k). With the petaloid appendages remov<strong>ed</strong>,<br />
the cyanthium can be seen. Male flowers (l), three are<br />
complete in the illustration, develop before the female<br />
flower.<br />
The female flower, in an enlarg<strong>ed</strong> drawing, shows<br />
the ovary’s 3 fus<strong>ed</strong> carpels (o), which contain ovules<br />
in axile placentation, the styles, and stigmas. The<br />
ovary develops into a schizocarp (p) fruit, which<br />
has green petaloid appendages (q) in this relat<strong>ed</strong><br />
species.<br />
COLOR CODE<br />
green: stem (a), leaves (b), p<strong>ed</strong>uncle (e),<br />
nectar glands (h), p<strong>ed</strong>icel (m, n),<br />
petal-like appendages (q)<br />
gray: stipules (c)<br />
white: latex (d)<br />
r<strong>ed</strong>: petal-like appendages (f, g)<br />
yellow: bracts (i), male flowers (l)<br />
light green: style (j), stigma (k), ovary (o)<br />
tan: schizocarp (p)
Grape Family (Vitaceae)<br />
This family consists mostly <strong>of</strong> climbing vines with tendrils<br />
that develop opposite the leaves. The tendrils<br />
may be twining, as in grape (Vitis), or end in attaching<br />
discs (see 16), as in Virginia creeper (Parthenocissus).<br />
Flower clusters also develop at the node opposite a<br />
leaf. The leaves are alternate, simple or pinnately or<br />
palmately compound. There are twelve genera and<br />
about 700 species.<br />
The minute flowers are bisexual or unisexual on the<br />
same plant (monoecious). Usually there are 4–7<br />
sepals, 4–7 petals, 4–7 stamens, and a single pistil,<br />
which develops into a berry fruit.<br />
Of interest...food: Vitis spp. (grape berries are<br />
us<strong>ed</strong> for making wine and jellies; dri<strong>ed</strong> gapes for<br />
raisins and currants); ornamentals: Cissus spp. (grape<br />
ivy), Parthenocissus quinquefolia (Virginia creeper),<br />
P. tricuspidata (Boston ivy).<br />
Vitis riparia River-bank Grape<br />
Lob<strong>ed</strong> leaves (a) with palmate venation are alternate<br />
to each other and opposite tendrils (b) on the stem (c).<br />
Tiny, unisexual, male and female flowers occur on this<br />
plant.<br />
Above the flower p<strong>ed</strong>icel (d) join<strong>ed</strong> sepals (e) appear as<br />
a wavy-margin<strong>ed</strong> cup in bud. The flower is cover<strong>ed</strong> with<br />
petals (f) join<strong>ed</strong> at the top. As the petals separate into<br />
5-6 lobes (g), the stamens’ filaments (h) and the nectar<br />
disc (i) are expos<strong>ed</strong>. When the petal cap is sh<strong>ed</strong>, the<br />
5-6 anthers (j) can be seen.<br />
The female flower, with the petal cap sh<strong>ed</strong>, consists <strong>of</strong><br />
sepal cup (k), nectar disc (l), and pistil compos<strong>ed</strong> <strong>of</strong><br />
a superior ovary (m) and a short style with a capitate<br />
(form<strong>ed</strong> like a head) stigma (n).<br />
Clusters <strong>of</strong> female flowers develop into the familiar<br />
bunch <strong>of</strong> grapes, botanically call<strong>ed</strong> berries (o, p).<br />
104<br />
COLOR CODE<br />
green: leaves (a), stem (c), p<strong>ed</strong>icels (d),<br />
sepal cup (e), p<strong>ed</strong>uncle (q),<br />
underdevelop<strong>ed</strong> berrry (p)<br />
r<strong>ed</strong>: tendril (b)<br />
light green: petals (f, g), ovary (m), stigma (n)<br />
dark green: nectar disc (i, l)<br />
white: filaments (h)<br />
yellow: anthers (j)<br />
purple: sepal cup (k)<br />
dark blue: berries (o)
Maple Family (Aceraceae)<br />
Maples have opposite branches and leaves. The leaves<br />
may be simple, with palmate venation, or compound as<br />
in box elder (Acer negundo, see 35). Species differ in<br />
leaf shape with margins entire or variously tooth<strong>ed</strong> or<br />
variously lob<strong>ed</strong>. The two genera (Diperonia from China<br />
and Acer) in this family are small to large deciduous<br />
trees found mainly in the North Temperate Zone.<br />
The flower in some species is bisexual, but usually<br />
it is unisexual with both male and female flowers on<br />
the same tree (monoecious) or separat<strong>ed</strong> on different<br />
trees (dioecious). Unisexual flowers may have vestigial<br />
organs <strong>of</strong> the opposite sex. There are usually 5<br />
sepals, 5 petals or none, 4–12 stamens, and a single<br />
pistil with a superior ovary. The 2 fus<strong>ed</strong> carpels <strong>of</strong> the<br />
ovary develop into a double samara fruit.<br />
Of interest...lumber: Acer saccharum (sugar maple),<br />
A. macrophyllum (big leaf maple); food: A. saccharum<br />
(sugar maple, all maple species yield sap with<br />
a high sugar content); ornamentals: A. saccharum<br />
(sugar maple), A. platanoides (Norway maple), A. pseudoplatanus<br />
(sycamore maple), A. ginnala (amur maple),<br />
A. palmatum (Japanese maple) with many cultivars for<br />
variously cut leaves and colors.<br />
Acer saccharinum Silver Maple<br />
This maple tree grows to 37 meters high. The main trunk<br />
divides near the ground into several upright stems. It is<br />
105<br />
a fast-growing tree with narrow-angl<strong>ed</strong> brittle branches<br />
and a spreading root system. Therefore, it should not<br />
be us<strong>ed</strong> for landscaping, even though many people use<br />
it for this purpose by mistake.<br />
Opposite leaves (a) are 5-lob<strong>ed</strong> with palmate venation<br />
(b) and tooth<strong>ed</strong> (dentate) margins. The leaf is green on<br />
the upper surface and silvery on the lower surface (c). In<br />
one location with two silver maple trees growing next to<br />
each other, the tree bearing male flowers in the spring<br />
produces yellow autumn leaves, while the other tree<br />
bearing female flowers in the spring has r<strong>ed</strong> autumn<br />
leaves.<br />
This species is dioecious and wind-pollinat<strong>ed</strong>, with<br />
flowers opening before the leaves (e) expand on the<br />
stem (f). Hair-fring<strong>ed</strong> bud scales (g) enclose clusters<br />
<strong>of</strong> male flowers (h). The male flower has join<strong>ed</strong> sepals<br />
(i), a variable number <strong>of</strong> stamens (j), and a vestigial<br />
pistil (k).<br />
Clusters <strong>of</strong> female flowers (l) are produc<strong>ed</strong> on another<br />
tree. The female flower consists <strong>of</strong> a sepal cup (m)<br />
and vestigial stamens (n), and the single pistil has an<br />
ovary consisting <strong>of</strong> 2 fus<strong>ed</strong> carpels (o) and 2 plumose<br />
(feathery) stigmas (p). Two ovules occur in each carpel,<br />
but only one develops, so that the fruit is a double<br />
samara (q) with a se<strong>ed</strong> (r) on each side. In suitable soil,<br />
there is almost 100% germination <strong>of</strong> the se<strong>ed</strong>s, another<br />
good reason not to use this plant in the landscape.<br />
COLOR CODE<br />
yellow: autumn leaves (a), male flowers (h),<br />
stamens (j, n)<br />
green: veins (b), leaf bud (e), stem (f),<br />
female flowers (l), stigmas (p)<br />
white: leaf lower surface (c), pistil (k),<br />
carpels (o)<br />
brown: stem (d), samara (q, r)<br />
r<strong>ed</strong>: bud scales (g)<br />
pale yellow: sepals (i, m)
Cashew Family (Anacardiaceae)<br />
Plants in this family usually have resin ducts in the<br />
tissues. The resin in some <strong>of</strong> these plants causes contact<br />
dermatitis in humans. Poison ivy, poison oak, and<br />
poison sumac are familiar examples.<br />
Trees, shrubs, and vines, with usually alternate and<br />
compound leaves, are present in this family. The small<br />
flowers form in branch<strong>ed</strong> clusters (panicles) and are<br />
bisexual or unisexual. Flower features are a prominent<br />
nectar disc and a pistil <strong>of</strong> fus<strong>ed</strong> carpels that form one<br />
se<strong>ed</strong> cavity in which one ovule develops. Fruits are usually<br />
drupes. There are about 80 genera and about 600<br />
species.<br />
Of interest...food: Anacardium occidentale (cashew),<br />
Mangifera indica (mango), Pistacia vera (pistachio);<br />
resins: Pistacia lentiscus (mastic tree), Toxicodendron<br />
vernicifera (varnish tree); tannic acid: Rhus typhina<br />
(staghorn sumac), Schinopsis; ornamentals: Cotinus<br />
coggygria (smoke tree), Rhus aromatica (fragrant<br />
sumac), Rhus copallina (shining sumac), R. typhina<br />
‘Laciniata’ (lacy-leaf<strong>ed</strong> staghorn sumac); poisonous:<br />
Metopium toxiferum (poison-wood, doctor gum coralsumac),<br />
Toxicodendron verniciflua (Japanese lacquertree),<br />
T. radicans (poison-ivy, poison-oak), T. diversiloba<br />
(Pacific poison-oak), T. vernix (poison-sumac).<br />
Rhus typhina Staghorn Sumac<br />
An extensive clone <strong>of</strong> shrubs may be form<strong>ed</strong> from one<br />
plant by new shoots arising from the root system. The<br />
106<br />
common name refers to the very hairy stem that has<br />
the appearance <strong>of</strong> new antlers. The leaves are alternate<br />
and compound, with opposite pairs <strong>of</strong> leaflets (a) on the<br />
petiole (b). In autumn, leaves become a brilliant r<strong>ed</strong>.<br />
In the spring, clusters <strong>of</strong> flowers form at the ends <strong>of</strong><br />
shoots. An individual plant has either male or female<br />
flowers with vestigial organs <strong>of</strong> the opposite sex. The<br />
male flower has 5 sepals (c), 5 petals (d), 5 stamens<br />
(e), and a vestigial pistil (f). Staminal filaments (g) arise<br />
beneath the nectar disc (h).<br />
The female flower has 5 sepals (j), 5 petals (k), 5<br />
vestigial stamens (l) and a single pistil with 3 stigmas<br />
(m). Arising from the nectar disc (n), the superior<br />
ovary (o) consists <strong>of</strong> three fus<strong>ed</strong> carpels containing one<br />
ovule.<br />
In autumn, plants with female flowers produce conspicuous<br />
upright clusters <strong>of</strong> drupes (p) on the ends<br />
<strong>of</strong> shoots. The drupe’s epidermis is cover<strong>ed</strong> with r<strong>ed</strong><br />
hairs (q). When partially remov<strong>ed</strong>, a single se<strong>ed</strong> (r) is<br />
expos<strong>ed</strong>.<br />
Cotinus coggygria Smoke Tree<br />
In late summer, this low structur<strong>ed</strong> tree is cover<strong>ed</strong> with<br />
what appears to be clouds <strong>of</strong> pink smoke. As the drupes<br />
(s) form, the surrounding hairy, filamentous stems (t)<br />
change from green to pink.<br />
COLOR CODE<br />
r<strong>ed</strong>: petiole (b)<br />
green: leaflets (a), sepals (c, j), p<strong>ed</strong>icel (i),<br />
leaf (u)<br />
yellow: anthers (e)<br />
white: pistil (f), filaments (g)<br />
light green: petals (d, k), stigmas (m), ovary (o),<br />
anthers (l)<br />
orange: nectar disc (h, n)<br />
dark r<strong>ed</strong>: drupes (p), hairs (q)<br />
tan: se<strong>ed</strong> (r)<br />
brown: drupes (s)<br />
pale pink: stems (t)
Rue Family (Rutaceae)<br />
Aromatic essential oils are produc<strong>ed</strong> in glands that<br />
appear as clear “dots” on the leaves. Another characteristic<br />
feature <strong>of</strong> this family is that within the usually<br />
bisexual flowers, the pistil has a superior, usually lob<strong>ed</strong><br />
ovary situat<strong>ed</strong> on a nectar disc.<br />
Rue family plants include trees, shrubs, and herbs,<br />
with many different fruit types represent<strong>ed</strong>. They include<br />
capsules, leather-rind berries (hesperidia), drupes,<br />
and samaras. There are 150 genera and about<br />
900 species.<br />
Of interest...food: Citrus 60 species, with many<br />
hybrids between species, Citrus sinensis (sweet<br />
orange), C. limon (lemon), C. paradisi (grapefruit), C.<br />
aurantifolia (lime), C. aurantium (Seville orange), C.<br />
reticulata (tangerine, manderin, satsuma), C. m<strong>ed</strong>ica<br />
(citron), Fortunella (kumquat), Pummelo; ornamentals:<br />
Calodendrum (Cape chestnut), Choisya ternata,<br />
Dictamnus (gas plant, fraxinella, dittany), Diosma, Murraya<br />
(orange jessamine), Phellodendron spp. (“cork”<br />
trees), Poncirus (trifoliate orange), Ptelea (hop tree,<br />
wafer ash), Ruta graveolens (common rue), Skimmia,<br />
Zanthoxylum americanum (prickly ash); lumber:<br />
Zanthoxylum flavum (West Indian silkwood); poisonous:<br />
Dictamnus, Ruta graveolens, Ptelea.<br />
Citus limon Lemon<br />
The small lemon tree has alternate, simple leaves (a)<br />
with translucent glands containing aromatic oil. Citrus<br />
107<br />
species’ leaves have various sizes <strong>of</strong> petiole wings (b).<br />
A grapefruit (C. paradisi) leaf (c) is shown for comparison<br />
<strong>of</strong> the wing<strong>ed</strong> petiole (d).<br />
Small, bisexual flowers, produc<strong>ed</strong> in clusters, are very<br />
fragrant. The 5 join<strong>ed</strong> sepals (f) form a cup. Inside the<br />
cup are 5 petals (g) and many stamens (h) <strong>of</strong> unequal<br />
lengths. Some <strong>of</strong> the filaments (i) are join<strong>ed</strong> together,<br />
and arise at the base <strong>of</strong> the nectar disc (j).<br />
The pistil is situat<strong>ed</strong> in the center <strong>of</strong> the disc surround<strong>ed</strong><br />
by the stamens, with the stigma (k) at anther (l, m) level.<br />
The pistil has a superior ovary (o), a single style (p)<br />
compos<strong>ed</strong> <strong>of</strong> fus<strong>ed</strong> canals leading to the carpels, and<br />
a single stigma (q). As the fruit (r) develops, the petals,<br />
stamens, and the style are sh<strong>ed</strong>.<br />
The fruit is a berry with a leathery rind (hesperidium).<br />
The rind or exocarp(s) has oil glands. Inside the rind is<br />
the spongy mesocarp tissue (t). Inside the mesocarp<br />
is the endocarp, which produces the juice sacs (u) <strong>of</strong><br />
enlarg<strong>ed</strong> cells.<br />
The se<strong>ed</strong> (v) contains a green chlorophyll-containing<br />
embryo, which may germinate within the fruit. This is<br />
call<strong>ed</strong> vivipary. The grapefruit leaf shown here is from<br />
a plant that was grown from a se<strong>ed</strong> that germinat<strong>ed</strong><br />
within a fruit.<br />
COLOR CODE<br />
green: leaf blade (a, c) petiole wings (b, d),<br />
p<strong>ed</strong>uncle (n), nectar disc (j), ovary (o),<br />
fruit (r)<br />
light green: p<strong>ed</strong>icel (e), sepal cup (f), stigma (k)<br />
white: petals (g), stamens (h), filaments (i),<br />
style (p), mesocarp (t) se<strong>ed</strong>s (v)<br />
yellow: anthers (l, m), exocarp (s), juice sacs (u)<br />
tan: stigma (q)
Geranium Family (Geraniaceae)<br />
Mostly herbs and some small shrubs are represent<strong>ed</strong><br />
in this family. Scent<strong>ed</strong> leaves in some species, a flower<br />
with parts in 5’s, and a beak<strong>ed</strong> or lob<strong>ed</strong> fruit are some <strong>of</strong><br />
the characteristics. There are eleven genera and about<br />
750 species.<br />
Leaves are alternate or opposite, and compound or simple<br />
with lobes or divisions. They usually have palmate<br />
venation and stipules. Usually in clusters, the bisexual<br />
flower has 5–15 stamens in whorls <strong>of</strong> 5 and a single pistil<br />
with 3–5 carpels in a superior ovary. Adhering to the<br />
ovary axis, the 3–5 styles aid in an unusual se<strong>ed</strong> dispersal<br />
mechanism. The fruit is a septicidal or loculicidal<br />
capsule.<br />
Of interest...ornamentals: Erodium spp. (stork’sbill,<br />
heron’s-bill), Geranium spp. (hardy geraniums,<br />
400 species). Some popular garden geraniums are<br />
G. cantabrigiense ‘Biokovo’, G. cinereum ‘Ballerina,’<br />
G. himalayense × G. pratense ‘Johnson’s Blue,’ G.<br />
‘Rozanne,’ G. sanguineum, G. macrorrhizum, G. ×<br />
magnificum. Pelargonium zonale is the geranium <strong>of</strong><br />
commerce and native to South Africa. Some with<br />
scent<strong>ed</strong> leaves include P. crispus (lemon-scent<strong>ed</strong>),<br />
P. graveolens (rose-scent<strong>ed</strong>), P. fulgidum (spicescent<strong>ed</strong>),<br />
P. tomentosum (peppermint-scent<strong>ed</strong>).<br />
Geranium maculatum Wild Geranium,<br />
Crane’s-bill<br />
This spring-flowering herb produces annual shoots<br />
from a thick perennial rhizome. Leaves (a) at the base <strong>of</strong><br />
108<br />
the plant have 5–7 lobes and long petioles (b), while upper<br />
leaves (c) have 5 lobes and shorten<strong>ed</strong> petioles (d).<br />
The leaves have stipules (f) and palmate venation.<br />
Flowers form in a flat-topp<strong>ed</strong> cluster with the central<br />
flower opening first (cyme). The flower has 5 persistent<br />
sepals (j) with spine-like tips (k), which are clearly seen<br />
when the petals are remov<strong>ed</strong>. Five lavender petals (l)<br />
have green veins (m).<br />
The 10 stamens (n) are in two whorls <strong>of</strong> 5 each around<br />
the base <strong>of</strong> the pistil (o). Staminal filaments (p) are attach<strong>ed</strong><br />
at the center <strong>of</strong> the anther (q) and flare outward<br />
at the bases. In the illustration, the anthers <strong>of</strong><br />
the inner whorl <strong>of</strong> stamens are open, exposing pollen<br />
grains, while the anthers <strong>of</strong> the outer whorl are not yet<br />
mature.<br />
The single pistil has a superior ovary (r) <strong>of</strong> 5 fus<strong>ed</strong><br />
carpels (s), 5 styles (t), which form a column around<br />
the ovary axis (u), and 5 stigmas (v). Between the petal<br />
bases are 5 nectar glands (w).<br />
Crane’s-bill, one <strong>of</strong> the common names, applies to the<br />
fruit, a beak<strong>ed</strong>, septicidal capsule. At the time <strong>of</strong> se<strong>ed</strong><br />
dispersal, the styles (t, x) attach<strong>ed</strong> to the carpels (s, y)<br />
coil elastically, which propels the se<strong>ed</strong>s (z) out <strong>of</strong> the<br />
carpel chambers.<br />
COLOR CODE<br />
green: blade (a, c), petiole (b, d), stem (e),<br />
p<strong>ed</strong>uncle (g), p<strong>ed</strong>icel (h), nectar<br />
glands (w)<br />
light green: stipules (f), bracts (i), sepals (j), petal<br />
veins (m), filament (p), pistil (o),<br />
carpels (s), styles (t), stigmas (v)<br />
light lavender: petals (l)<br />
r<strong>ed</strong>: sepal tips (k)<br />
yellow: stamens (n), anther (q)<br />
tan: ovary axis (u), styles (x), carpels (y),<br />
se<strong>ed</strong> (z)
Carrot Family (Apiaceae)<br />
Members <strong>of</strong> this family form flowers in a dense, flattopp<strong>ed</strong><br />
cluster (umbel, the reason for the old family<br />
name, Umbelliferae). Below the umbel, there is <strong>of</strong>ten a<br />
whorl <strong>of</strong> bracts. The number <strong>of</strong> sepals, petals and stamens<br />
<strong>of</strong> an individual flower in a cluster are each 5.<br />
The single pistil has an inferior ovary made up <strong>of</strong><br />
2 carpels, an ovule in each. After fertilization, the ovary<br />
develops into a schizocarp fruit, which splits apart into<br />
2 mericarps that function as achenes (see 38).<br />
Also characteristic <strong>of</strong> plants in this family are the usually<br />
stem-sheathing leaf petioles. Compund leaf blades are<br />
usually several times divid<strong>ed</strong> into leaflets. Aromatic oils<br />
are present in leaves, stems, flowers, and fruits <strong>of</strong> these<br />
mostly biennial or perennial herbs. There are about 300<br />
genera and over 3,000 species.<br />
Of interest...food and flavoring: Anethum graveolens<br />
(dill), Angelica, Anthriscus cerefolium (chervil), Apium<br />
graveolens (celery), Carum carvi (caraway), Coriandrum<br />
sativum (coriander), Cuminum cyminium (cumin),<br />
Daucus carota cultivars (carrot), Foeniculum vulgare<br />
(fennel), Levisticum <strong>of</strong>ficinale (lovage), Myrrhis odorata<br />
(sweet cicely), Pastinaca sativa (parsnip), Petroselinum<br />
crispum (parsley), Pimpinella anisum (anise);<br />
ornamentals: Aegopodium podograria (goutwe<strong>ed</strong>,<br />
bishop’s we<strong>ed</strong>), Ammi majus (lacy false bishop’s we<strong>ed</strong>),<br />
Astrantia major (masterwort), Heracleum lanatum (cow<br />
parsnip), Trachymeme (blue lace-flower); poisonous:<br />
Cicuta maculata (water hemlock), Conium maculatum<br />
(hemlock), Heracleum mantegazzianum (giant hogwe<strong>ed</strong>).<br />
Cases <strong>of</strong> poisoning <strong>of</strong> humans and animals by<br />
plants are mainly caus<strong>ed</strong> by ingestion or skin contact.<br />
Some plants are poisonous only at certain stages <strong>of</strong><br />
growth or certain times <strong>of</strong> the year. Cicuta maculata (water<br />
hemlock) grows mainly in wet areas and poisons cattle<br />
foraging in wet pastures in the spring. A small piece<br />
the size <strong>of</strong> a walnut is enough to kill a cow. Cicutoxin<br />
is concentrat<strong>ed</strong> in the roots, but is present in all parts<br />
<strong>of</strong> the plant. In humans if mistaken as roots <strong>of</strong> parsnips,<br />
Jerusalem artichokes or other roots, when eaten, the<br />
results are fatal. Conium maculatum (poison hemlock)<br />
was the plant that caus<strong>ed</strong> the death <strong>of</strong> Socrates. The<br />
plant, native to Eurasia, has become naturaliz<strong>ed</strong> in the<br />
Unit<strong>ed</strong> States. It causes paralysis <strong>of</strong> the lungs. Heracleum<br />
mantegazzianum (giant hogwe<strong>ed</strong>) is not only an<br />
invasive plant but causes painful blisters on contact with<br />
human skin. This is call<strong>ed</strong> “contact dermatitis.”<br />
109<br />
Daucus carota Wild Carrot, Queen Anne’s Lace<br />
Wild carrot plants are biennial herbs, producing a basal<br />
rosette (a) <strong>of</strong> leaves and a tap root (b) the first year,<br />
with stem-borne leaves, flowers, and fruits the second<br />
year. The alternate, feathery-compound leaves (c) have<br />
petiole bases (d) that sheath the stem (e). This plant<br />
is not consider<strong>ed</strong> a “wild food,” as it greatly resembles<br />
other extremely poisonous plants in this family, which<br />
can be confus<strong>ed</strong> with it. Moreover, the fibrous white<br />
tap-roots are not <strong>ed</strong>ible like the orange, β-carotenecontaining<br />
tap roots <strong>of</strong> cultivat<strong>ed</strong> carrot.<br />
The umbel <strong>of</strong> flowers is support<strong>ed</strong> by a p<strong>ed</strong>uncle (f) and<br />
has a whorl <strong>of</strong> compound bracts (g) below. The stems<br />
that branch out above the bracts are primary rays (h).<br />
Secondary rays or p<strong>ed</strong>icels (i) support flowers in small<br />
clusters (umbellets, j) subtend<strong>ed</strong> by bractlets (k). This<br />
arrangement is term<strong>ed</strong> a compound umbel. Outer<br />
flowers <strong>of</strong> the umbel have larger petals to attract pollinators,<br />
and the one center flower (l) has deep r<strong>ed</strong> petals.<br />
Lacking sepals, a carrot flower consists <strong>of</strong> 5 petals (m),<br />
which are occasionally pink instead <strong>of</strong> white, 5 stamens<br />
(n), and a single pistil. In the flower drawing, because<br />
<strong>of</strong> the pistil’s inferior (below other flower parts) ovary,<br />
only the 2 styles (o) on stylopodia (p) can be seen. The<br />
stylopodium is a nectar-secreting organ that attracts<br />
a variety <strong>of</strong> pollinating insects. Cross-pollination with<br />
other plants is not necessary, because the flowers are<br />
self-fertile.<br />
As the fruit develops, the parts <strong>of</strong> the pistil become more<br />
obvious. A stylopodium (p) with style (o) and stigma (q)<br />
is atop each carpel, the mericarp (r) <strong>of</strong> the schizocarp<br />
fruit. Hook<strong>ed</strong> spines (s), which catch in animal fur, facilitate<br />
fruit dispersal. Fruit is also wind-dispers<strong>ed</strong>. In autumn,<br />
the umbel <strong>of</strong> schizocarps (t) close inward to form<br />
a “bird’s-nest” in appearance. It closes in wet weather<br />
and opens when dry, further aiding fruit dispersal.<br />
COLOR CODE<br />
green: leaf (c), petiole (d), stem (e),<br />
p<strong>ed</strong>uncle (f), bracts (g), ray (h),<br />
p<strong>ed</strong>icel (i)<br />
white: root (b), flowers (j), petals (m)<br />
r<strong>ed</strong>: center flower (l)<br />
yellow: stamens (n)<br />
light green: styles (o), stylopodium (p), stigma (q)<br />
tan: mericarp (r), spines (s), schizocarps (t)
Milkwe<strong>ed</strong> Family (Asclepiadaceae)<br />
The common characteristic in this family is an unusual<br />
flower (shown in the illustrat<strong>ed</strong> example). Otherwise,<br />
the appearance <strong>of</strong> these plants varies enormously. This<br />
family includes sturdy perennial herbs, shrubs, dainty<br />
vines, small trees, and succulent plants that resemble<br />
cacti. Usually, the stems have a milky, latex-containing<br />
sap. Simple leaves are in an opposite or whorl<strong>ed</strong> arrangement,<br />
but are sometimes alternate. There are<br />
about 250 genera and 2,000 species. Flowers occur<br />
singly or in various types <strong>of</strong> clusters. The fruit is a<br />
follicle that splits along one seam.<br />
Of interest...ornamentals: Araujia seric<strong>of</strong>era, Asclepias<br />
tuberosa (butterfly we<strong>ed</strong>), A. curassavica (bloodflower),<br />
Ceropegia woodii (string-<strong>of</strong>-hearts), Cryptostegia<br />
grandiflora (purple allamanda), Hoya carnosa (wax<br />
plant), Huernia, Oxypetalum caeruleum (blue milkwe<strong>ed</strong>),<br />
Stapelia (carrion flower), Stephanotis floribunda<br />
(Madagascar jasmine); we<strong>ed</strong>: Asclepias Cornuti (common<br />
milkwe<strong>ed</strong>, silkwe<strong>ed</strong>), Asclepias incarnata (swamp<br />
milkwe<strong>ed</strong>). Asclepias Cornuti (common milkwe<strong>ed</strong>) produces<br />
a milky acrid sap. Monarch butterfly larvae fe<strong>ed</strong><br />
on the milkwe<strong>ed</strong> leaves which renders adults bad tasting<br />
to birds. This is advertis<strong>ed</strong> in their distinctive orange<br />
and black coloration. The somewhat smaller Viceroy<br />
butterfly mimics the coloration <strong>of</strong> the Monarch and<br />
avoids being attack<strong>ed</strong>, even though as a willow-fe<strong>ed</strong>er,<br />
it is <strong>ed</strong>ible to birds. The common name silkwe<strong>ed</strong> refers<br />
to the use in former times <strong>of</strong> the silky se<strong>ed</strong> as insulation<br />
in clothing and down in pillows.<br />
Cryptostegia grandiflora (India rubber vine, purple allamanda)<br />
from Madagascar was us<strong>ed</strong> to produce a commercial<br />
source <strong>of</strong> poor quality rubber latex. Now, this<br />
twining vine is us<strong>ed</strong> as an ornamental because <strong>of</strong> its<br />
beautiful flowers. Caution must be us<strong>ed</strong> when pruning,<br />
as the poisonous sap is very irritating to the skin.<br />
Matelea has sap once us<strong>ed</strong> as arrow poison. The old<br />
name Vincetoxicum is Greek for “subduing poison.”<br />
Asclepias tuberosa Butterfly-we<strong>ed</strong><br />
This perennial herb is an attractive, orange-flower<strong>ed</strong><br />
plant that does not have milky sap and can be cut for<br />
floral arrangements. The hairy stems (a) have alternate,<br />
lanceolate leaves (b) and terminate in flat-topp<strong>ed</strong> flower<br />
clusters (umbels). An umbel is a type <strong>of</strong> cluster in which<br />
110<br />
the p<strong>ed</strong>uncle (c) has many p<strong>ed</strong>icels (d) arising at a common<br />
point, each supporting a flower (e). Individually, this<br />
specializ<strong>ed</strong> flower has 5 sepals (f) and 5 reflex<strong>ed</strong> petals<br />
(g) that cover the sepals. Above the petals is a structure<br />
compos<strong>ed</strong> <strong>of</strong> a gynostegium (h) surround<strong>ed</strong> by<br />
a crown <strong>of</strong> 5 nectar horns. Each nectar horn consists<br />
<strong>of</strong> an upright hood (i) and a protruding crest (j). With<br />
nectar horns remov<strong>ed</strong>, the central portion <strong>of</strong> the gynostegium<br />
can be seen. In the area between the nectar<br />
horn attachments are 2 flaps (veils, k) with an opening<br />
between. A pin is shown insert<strong>ed</strong> in this side opening.<br />
When the pin is rais<strong>ed</strong> through the slit opening, it dislodges<br />
another structure, a pair <strong>of</strong> pollinia, tuck<strong>ed</strong> into<br />
top-opening slits in the gynostegium. A pair <strong>of</strong> pollinia<br />
is a male part <strong>of</strong> the flower; there are five pairs. Each<br />
pair consists <strong>of</strong> 2 anther sacs (l) with arms (m), connecting<br />
them to a gland (n).<br />
The female part <strong>of</strong> the gynostegium cannot be seen<br />
from the outside. By opening two side flaps (k), the<br />
sticky stigmatic tissue (o) is expos<strong>ed</strong>. There are 5 sets<br />
<strong>of</strong> flaps with stigmatic tissue between each, connecting<br />
internally to 2 styles (p). Below each style is a carpel<br />
(q), where numerous ovules (r) are attach<strong>ed</strong> in parietal<br />
placentation. So, all together, this flower has a<br />
single pistil compos<strong>ed</strong> <strong>of</strong> 2 ovaries (s) <strong>of</strong> a carpel each,<br />
2 styles, and enlarg<strong>ed</strong> 5-lob<strong>ed</strong> stigma.<br />
How does a bee react to this flower? Bees are attract<strong>ed</strong><br />
to the nectar in the nectar horns. To position itself, the<br />
bee lands on the gynostegium. When a leg or an antenna<br />
slips between the side flaps, it is rais<strong>ed</strong> up (as<br />
the pin shown) and catches a pair <strong>of</strong> pollinia. Apparently,<br />
this does not bother the bee. With repeat<strong>ed</strong> slipping<br />
and sliding <strong>of</strong> many bees on many flowers, pollinia<br />
are remov<strong>ed</strong> from the top-opening slits and insert<strong>ed</strong> in<br />
the side-opening flaps, achieving a high percentage <strong>of</strong><br />
pollination. The fruits that result are follicles (t) <strong>of</strong> hairy<br />
se<strong>ed</strong>s (u).<br />
COLOR CODE<br />
green: stem (a), leaf (b), p<strong>ed</strong>uncle (c),<br />
p<strong>ed</strong>icel (d), sepal (f)<br />
orange: flower (e), petal (g), hood (i), crest (j)<br />
pale green: gynostegium (h, k), stigma (o), styles (p),<br />
carpel (q), ovary (s)<br />
yellow: anther sacs (l)<br />
tan: anther arms (m)<br />
brown: anther gland (n)<br />
white: ovules (r)
Nightshade Family (Solanaceae)<br />
There is no single characteristic common only to this<br />
family. A number <strong>of</strong> features are present. Flower petal<br />
lobes tend to overlap or have creases in a petal tube<br />
that in bud is fold<strong>ed</strong> fan-like. And, usually, the stamens<br />
are attach<strong>ed</strong> to the petals. Numerous ovules develop<br />
into numerous se<strong>ed</strong>s in the berry or capsule fruit.<br />
The leaves are mostly alternate and simple, but size and<br />
shape vary greatly throughout the family. Usually the<br />
leaves are hairy and have a characteristic odor. Plant<br />
form ranges from herb to shrub to tree to vine. There<br />
are 90 genera and about 3,000 species.<br />
Of interest...ornamentals: Browallia, Datura arborea<br />
(angel’s trumpet), Nicotiana (tobacco, see 34), Nierembergia,<br />
Petunia, Physalis alkelengi (Chinese lantern),<br />
Schizanthus, Solandra (cup <strong>of</strong> gold); poisonous:<br />
Atropa Belladonna (deadly nightshade, belladonna,<br />
atropine), Datura stramonium (jimson we<strong>ed</strong>), Nicotiana<br />
(tobacco, nicotine insecticide), Physalis heterophylla<br />
(ground cherry), Solanum Dulcamara (bitter<br />
nightshade), S. nigrum (black nightshade), S. pseudocapsicum<br />
(Jerusalem cherry); m<strong>ed</strong>icinal: Hyoscyamus<br />
niger (henbane, a source <strong>of</strong> alkloidal drugs),<br />
Atropa belladonna (source <strong>of</strong> alkaloids, atropine and<br />
hyoscyamine), Datura Stramonium (source <strong>of</strong> alkaloid<br />
drug hyoscyamine); food: Capsicum spp. (bell pepper,<br />
chilies, cayenne pepper, paprika), Lycoperiscon<br />
esculentum (tomato), Physalis ixocarpa (tomatillo, jamberry),<br />
P. peruviana (strawberry tomato, cape gooseberry,<br />
ground cherry), P. pruinosa (strawberry tomato),<br />
Solanum Melongena variety esculentum (eggplant,<br />
aubergine), S. tuberosum (potato, Irish potato).<br />
Potatoes are native to the central Andes <strong>of</strong> Peru.<br />
Indians collect<strong>ed</strong> wild potatoes before 6,000 B.C.E.<br />
There are eight species and as many as 5,000 varieties<br />
in many colors. Potatoes can grow almost anywhere except<br />
in high humidity areas. Potatoes are 99.9% fat-free<br />
and have a higher percentage <strong>of</strong> protein than soybeans.<br />
One potato supplies 1 /2 <strong>of</strong> the daily vitamin C requirement<br />
for an adult. As a crop, potatoes are worth billions<br />
<strong>of</strong> dollars. In the mid-1800s, due to the potato late blight<br />
(caus<strong>ed</strong> by the fungus Phytophthora infestans,see 46)<br />
millions <strong>of</strong> people di<strong>ed</strong> <strong>of</strong> famine in Ireland with the loss<br />
<strong>of</strong> potato crops. Half <strong>of</strong> the world’s crop is f<strong>ed</strong> to livestock.<br />
It is also us<strong>ed</strong> to make vodka and aquavit, and<br />
can be us<strong>ed</strong> as starch, paste, and dye. As fuel for cars,<br />
one acre (0.40 hectares) <strong>of</strong> potatoes yields 1,200 gallons<br />
(4536 liters) <strong>of</strong> ethyl alcohol in a year.<br />
111<br />
Solanum dulcamara Bitter Nightshade<br />
Leaves on this wild, perennial vine are alternate and<br />
divid<strong>ed</strong> into 3 lobes (a). Flowers in the cymose cluster<br />
have joint<strong>ed</strong> p<strong>ed</strong>icels (c, d). (A cyme is a flat-topp<strong>ed</strong><br />
cluster with the central flower opening first.) There are<br />
5 join<strong>ed</strong> sepals (e) and 5 reflex<strong>ed</strong>, purple petals (f) with<br />
green spots (g) at the base. The 5 stamens with short<br />
purple filaments (h) join anthers (i) around the pistil’s<br />
style (j).<br />
With the flower cut open, the stamens (h, i, k) surround<br />
the pistil’s superior ovary (l) and style (j, m), with<br />
the stigma (n) emerging at the top. Pollen is releas<strong>ed</strong><br />
from the stamens through pores (o) at the ends <strong>of</strong> the<br />
anthers. Nightshade fruits are small, r<strong>ed</strong>, poisonous<br />
berries (p).<br />
Lycopersicon esculentum Tomato<br />
Tomato flowers consist <strong>of</strong> join<strong>ed</strong> sepals (q) with 6 lobes,<br />
join<strong>ed</strong> petals (r) with 6 lobes, 6 stamens, and a single<br />
pistil. The stamens have short filaments and elongate,<br />
narrow-tipp<strong>ed</strong> anthers (s) that converge around the pistil’s<br />
style (t). Pollen is sh<strong>ed</strong> through longitudinal slits on<br />
the anthers’ inner surfaces.<br />
Physalis alkekengi Chinese Lantern<br />
A fruit that looks like a Chinese lantern is compos<strong>ed</strong> <strong>of</strong><br />
an enlarg<strong>ed</strong> sepal tube (v), which encloses an oranger<strong>ed</strong><br />
berry.<br />
Capsicum grossum Bell Pepper<br />
Pepper’s fruit type is a berry whose rind (w) changes<br />
from green to r<strong>ed</strong> at maturity. Se<strong>ed</strong>s (x) develop on a<br />
central placenta (y).<br />
COLOR CODE<br />
green: leaf (a), petiole (b), p<strong>ed</strong>icel (c, u),<br />
sepals (e, q), spots (g), style (j, t)<br />
purple: p<strong>ed</strong>icel (d), petals (f), filament (h)<br />
yellow: anthers (i, s), stamens (k), petals (r)<br />
light green: ovary (l), style (m), stigma (n)<br />
r<strong>ed</strong>: berries (p), rind (w)<br />
orange: sepal tube (v)<br />
white: se<strong>ed</strong>s (x), placenta (y)
Morning Glory Family<br />
(Convolvulaceae)<br />
Flowers in this family <strong>of</strong>ten have fus<strong>ed</strong> petals that are<br />
twist<strong>ed</strong> when in bud and open in a funnel-shape or in a<br />
tube shape with a flat top. A pair <strong>of</strong> bracts usually subtends<br />
the usually bisexual flower. Sepals, petals, and<br />
stamens are each 5, with the stamens arising from the<br />
petals. There is a single pistil with a superior ovary compos<strong>ed</strong><br />
<strong>of</strong> usually 2 carpels, which, when mature, form a<br />
loculicidal capsule. The plant tissues contain joint<strong>ed</strong><br />
latex-containing cells that produce a milky sap.<br />
Represent<strong>ed</strong> in this family are twining herbs, shrubs,<br />
and small trees. Heart-shap<strong>ed</strong>, alternate, and simple<br />
leaves are most common. There are about 50 genera<br />
and about 1,800 species.<br />
Of interest...food: Ipomoea batatas (sweet potato);<br />
ornamentals: Calonyction aculeatum (moonflower),<br />
Convolvulus althaeoides, C. cneorum (silverbush),<br />
C. mauritanicus (ground morning glory), Dichondra<br />
(a ground cover), Ipomea purpurea (morning glory),<br />
I. tuberosa (wood rose), Porana paniculata (Christmas<br />
vine), Quamoclit pennata (cypress vine); we<strong>ed</strong>s: Convolvulus<br />
spp. (bindwe<strong>ed</strong>s, which are drought-resistant<br />
due to their deep and extensive root systems.), Cuscuta<br />
(dodder, a parasitic plant with orange, thread-like stems<br />
that grow en masse in association with many different<br />
kinds <strong>of</strong> flowering plant hosts).<br />
112<br />
Convolvulus sepium H<strong>ed</strong>ge Bindwe<strong>ed</strong><br />
This plant is a perennial herb with a twining stem (a) and<br />
alternate, triangular leaves (b). Single flowers on long<br />
p<strong>ed</strong>uncles (c) arise in the leaf axils. At the base <strong>of</strong> the<br />
flower are 2 large bracts (d). Inside the bracts, 5 sepals<br />
(e) surround the funnelform tube <strong>of</strong> 5, pink, fus<strong>ed</strong> petals<br />
(f). The center <strong>of</strong> each petal lobe has a white stripe (g).<br />
With the petal tube cut open, the stamens’ petal attachment<br />
can be seen. Five filaments (h) arise from<br />
the petal tube and the anthers (i) meet and enclose the<br />
pistil’s stigma. Pollen is sh<strong>ed</strong> inwardly.<br />
With sepals, petals, and stamens remov<strong>ed</strong>, the parts <strong>of</strong><br />
the pistil can be seen. There are 2 stigmas (j), a single<br />
style (k), and an ovary (l) compos<strong>ed</strong> <strong>of</strong> 2 fus<strong>ed</strong> carpels,<br />
forming one chamber. Within the chamber are 4 ovules<br />
(m). An orange disc (n), surrounding the base <strong>of</strong> the<br />
pistil, arises from the receptacle (o).<br />
Ipomoea batatas Sweet Potato<br />
Cultivat<strong>ed</strong> for its <strong>ed</strong>ible, underground, tuberous roots<br />
(p), the sweet potato plant is a tropical vine, but can be<br />
grown in southern temperate regions during summer<br />
months.<br />
COLOR CODE<br />
r<strong>ed</strong>-green: stem (a)<br />
green: leaf (b, q), p<strong>ed</strong>uncle (c), bracts (d)<br />
light green: sepals (e)<br />
white: stripe (g), filaments (h), anthers (i),<br />
stigma (j), style (k), ovary (l), ovules (m),<br />
receptacle (o)<br />
pink: petals (f)<br />
orange: disc (n), tuber (p)
Mint Family (Lamiaceae)<br />
Mint plants have square stems and mostly opposite<br />
leaves. Aromatic essential oils are usually present<br />
and account for the distinct and characteristic odors.<br />
Flowers have 5 fus<strong>ed</strong> petals that diverge into 2 lips<br />
(bilabiate). (The old family name, Labiatae, means 2lipp<strong>ed</strong>,<br />
where the corolla or calyx is divid<strong>ed</strong> into two differently<br />
shap<strong>ed</strong> parts forming an upper and lower lip.)<br />
The single pistil has a superior, 4-lob<strong>ed</strong> ovary, and a<br />
style that arises between the ovary lobes from the base<br />
<strong>of</strong> the flower (gynobasic style). The fruits produc<strong>ed</strong><br />
are 4 nutlets.<br />
Usually, plants in this family are annual or perennial<br />
herbs, although shrubs, trees, and vines are also represent<strong>ed</strong>.<br />
There are about 200 genera and about 5,600<br />
species.<br />
Of interest...<strong>ed</strong>ible herbs: Majorana (marjoram),<br />
Mentha spp. (mints), Nepeta (catnip, catmint), Ocimum<br />
(basil), Origanum (oregano), Rosmarinus <strong>of</strong>ficinalis<br />
(rosemary), Salvia <strong>of</strong>ficinalis (sage), Satureja (savory),<br />
Thymus (thyme); ornamentals: Agastache barberi<br />
(giant hyssop), Ajuga (bugloss), Hyssopus (hyssop),<br />
Lamium (dead nettle), Lavandula (lavender), Nepeta<br />
(catmint), Perovskia (Russian sage), Phlomis alpina,<br />
Physostegia (false dragonhead, ob<strong>ed</strong>ient plant), Salvia<br />
splendens (scarlet sage), S. viridis (paint<strong>ed</strong> sage),<br />
Scutelaria costaricaca, Solenostemon scutellanoides<br />
(coleus), Stachys macrantha (big betony), S. byzantina<br />
(lamb’s ears).<br />
113<br />
Salvia <strong>of</strong>ficinalis Sage<br />
This spring-flowering, perennial herb has square stems<br />
(a) with opposite, simple leaves (b). Two small flower<br />
clusters arise on opposite sides <strong>of</strong> the stem. Conspicuous<br />
ribs join the flower’s 5-lob<strong>ed</strong> sepal tube (c). The<br />
5 fus<strong>ed</strong> petals (d) separate into an upper lip compos<strong>ed</strong><br />
<strong>of</strong> 2 petal lobes and a lower lip consisting <strong>of</strong> 3 petal<br />
lobes.<br />
Cut open, the flower reveals several interesting features.<br />
Two stamens arise from the lower petal lip. For<br />
clarity, one stamen is shad<strong>ed</strong> in the drawing. The filament<br />
(e) attaches to an enlarg<strong>ed</strong> connective (f) that<br />
allows for rotation <strong>of</strong> the anther sac (g), hence facilitating<br />
pollen dispersal by insects.<br />
As a visiting bee alights on the lower petal lip, pollen<br />
from the rotating anther sacs brushes the insect. After<br />
depletion <strong>of</strong> pollen, the stigmas (h) are lower<strong>ed</strong> by<br />
the elongat<strong>ed</strong> style (i). Thus, pollen from other flowers<br />
is brush<strong>ed</strong> on the stigmas by visiting bees, effecting<br />
cross-pollination.<br />
Nectar, the source <strong>of</strong> attraction to insects, is pool<strong>ed</strong> below<br />
a ring <strong>of</strong> hairs (j) in the petal tube, secret<strong>ed</strong> by a disc<br />
(k) at the base. The pistil’s gynobasic style (I) arises<br />
between the 4 lobes <strong>of</strong> the ovary (l).<br />
At fruiting time, when the persistent sepal tube is cut<br />
open, 4 nutlets (n) are reveal<strong>ed</strong>.<br />
COLOR CODE<br />
green: stem (a), p<strong>ed</strong>icel (m)<br />
gray-green: leaves (b)<br />
purple-green: sepals (c)<br />
purple: petals (d), nectar disc (k), stigmas (h),<br />
style (i)<br />
white: filaments (e), connectives (f), hairs (j)<br />
tan: nutlets (n)<br />
yellow: anther sacs (g)<br />
light green: ovary (l)
Olive Family (Oleaceae)<br />
Characteristics in this family include flower parts in 2’s<br />
with the anthers <strong>of</strong> the stamens usually touching. The<br />
single pistil has a superior ovary <strong>of</strong> 2 fus<strong>ed</strong> carpels with,<br />
usually, 2 ovules in each carpel.<br />
Plants in this family are shrubs, trees, and vines with<br />
opposite leaves, which may be simple or compound.<br />
Some have evergreen, persistent leaves. Usually, the<br />
flowers are bisexual and have 4 sepals and 4 petals.<br />
Fruit types are berries, drupes, capsules and samaras.<br />
There are 29 genera with 600 species.<br />
Of interest...food: Olea europaea (olive); lumber:<br />
Fraxinus (ash); ornamentals: Abeliophyllum (white<br />
forsythia, Korean abelia-leaf), Chionanthus (fringe<br />
tree), Forsythia (golden bells), Jasminum (jasmine),<br />
Ligustrum (privet), Osmanthus (fragrant olive, tea olive,<br />
devil-we<strong>ed</strong>), Syringa (lilac).<br />
In the countries surrounding the M<strong>ed</strong>iterranean Sea,<br />
the olive tree, Olea europaea, has been in cultivation<br />
for over 4,000 years. The drupe fruit has a high oil<br />
content that is us<strong>ed</strong> both for oil production and preserv<strong>ed</strong><br />
whole. Once trees are no longer productive, the<br />
wood is us<strong>ed</strong> to carve items such as bowls, jewelry, and<br />
roseries.<br />
In primitive naturalistic religions, it was believ<strong>ed</strong> that<br />
“spirits” inhabit<strong>ed</strong> certain trees. The olive tree had special<br />
significance as one <strong>of</strong> the most sacr<strong>ed</strong>. In summer,<br />
if a person slept under the tree, he <strong>of</strong> she would have<br />
pleasant dreams, as the evil spirits are afraid <strong>of</strong> the olive<br />
tree!<br />
Olive leaves were burn<strong>ed</strong> for protection from the “evil<br />
eye.” Accordingly, it was wise to have an olive tree<br />
plant<strong>ed</strong> near the dwelling place. On the Acropolis in<br />
Athens, Greece an olive tree is always growing near<br />
the Parthenon. Purport<strong>ed</strong>ly, the “evil eye” is the suppos<strong>ed</strong><br />
power <strong>of</strong> some people to harm others by merely<br />
looking at them.<br />
Olive leaves, woven into crown wreaths, were us<strong>ed</strong> by<br />
the Greeks and Romans to reward winners in athletic<br />
games.<br />
An olive branch is traditionally a symbol <strong>of</strong> peace. On<br />
the seal <strong>of</strong> the Unit<strong>ed</strong> States, the American eagle faces<br />
toward an olive branch clutch<strong>ed</strong> in its right foot as<br />
oppos<strong>ed</strong> to the cluster <strong>of</strong> spears in its left foot.<br />
114<br />
Syringa vulgaris Common Lilac<br />
Persia (now Iran) is the original home <strong>of</strong> the common<br />
lilac. The leaves (c) <strong>of</strong> this shrub are opposite, simple,<br />
and have entire margins. Clusters <strong>of</strong> fragrant, tubular<br />
flowers (d) branch from a main flower axis (compound<br />
panicle). Flowers last only a few weeks but are<br />
a favorite for the scent and old-fashion<strong>ed</strong> associations.<br />
There are many nam<strong>ed</strong> cultivars. A loculicidal capsule<br />
(e) is the fruit type.<br />
Forsythia Golden Bells<br />
Originally from China, Forsythia was brought to<br />
Europe in 1844. Of the many species, special cultivars<br />
and hybrids have been develop<strong>ed</strong>. This shrub’s flowers<br />
emerge along the stem (f) in early spring. Although the<br />
shrub is hardy in the Northern Hemisphere, flower buds<br />
are frequently kill<strong>ed</strong> by late frosts. In its natural form,<br />
arching branches are cover<strong>ed</strong> with yellow flowers.<br />
The flower has 4 sepals (h) and 4 petals (i) join<strong>ed</strong> at<br />
the base. Arising from the petal tube are 2 stamens<br />
(j) with back-to-back anthers. The pistil’s ovary (k) has<br />
many ovules (l) in axile placentation in each <strong>of</strong> the two<br />
carpels (m). There is a single style (n) and a 2-lob<strong>ed</strong><br />
stigma (o).<br />
Ligustrum vulgare Common Privet<br />
This plant is commonly us<strong>ed</strong> as a clipp<strong>ed</strong> h<strong>ed</strong>ge. If left<br />
to grow in its natural form, it produces fragrant flowers<br />
and can grow to 15 feet (5 meters) high. A drupe (r) is<br />
the fruit type <strong>of</strong> this shrub.<br />
Fraxinus pennsylvanica Green Ash<br />
The fruit on ash trees is a samara (t). The green ash<br />
tree is highly susceptible to the green ash tree borer<br />
insect pest; as a result, scores <strong>of</strong> green ash trees in<br />
Eastern Unit<strong>ed</strong> States are now dying or dead.<br />
COLOR CODE<br />
brown: stem (a, s), capsule (e)<br />
green: new shoots (b), leaves (c, g, q),<br />
sepals (h), p<strong>ed</strong>icel (p)<br />
lilac: flowers (d)<br />
tan: stem (f), samara (t)<br />
yellow: petals (i), stamens (j)<br />
pale green: ovary (k), style (n), stigma (o)<br />
white: ovules (l)<br />
dark blue: drupes (r)
Figwort Family (Scrophulariaceae)<br />
Plants in this large family <strong>of</strong> 210 genera have characteristics<br />
found in many relat<strong>ed</strong> families. They are<br />
mostly herbs or small shrubs that have various methods<br />
<strong>of</strong> obtaining nutrition, which include self-fe<strong>ed</strong>ing<br />
(autotrophic), partial dependence on another plant<br />
(hemiparasitic), total dependence (holoparasitic),<br />
and dependence on dead or decaying organic matter<br />
(saprophytic).<br />
Usually, the leaves are alternate on round or square<br />
stems. Flower types vary greatly, but all are bisexual.<br />
Bracts below flowers are usually present. Flower sepals<br />
are usually join<strong>ed</strong> and have 4-5 lobes. Join<strong>ed</strong> petals<br />
form a tube that may have 2 lips (bilabiate) like a mint<br />
flower. Sometimes there are 5 stamens, but usually,<br />
there are 4 in 2 pairs <strong>of</strong> two different lengths (didynamous),<br />
with, usually, the fifth stamen r<strong>ed</strong>uc<strong>ed</strong> to a<br />
sterile structure or a scale.<br />
The single pistil has a superior ovary, or 2 carpels forming<br />
2 chambers, that usually matures into a capsule<br />
fruit.<br />
Of interest...ornamentals: Angelonia (angelonia),<br />
Alonsoa (mask flower), Antirrhinum (snapdragon), Calceolaria<br />
(slipper-flower), Cymbalaria (Kenilworth ivy),<br />
Diascia (twinspur), Mazus reptans, Mimulus (monkeyflower),<br />
Penstamon (beard-tongue), Russelia (coral<br />
plant), Satera (bacopa), Torenia (wishbone flower);<br />
wild: Castilleja coccinea (Indian paint-brush), P<strong>ed</strong>icularis<br />
(lousewort), Scrophularia (figwort), Verbascum<br />
(mullein), Veronica (spe<strong>ed</strong>well), Veronicastrum<br />
(Culver’s-root); poisonous: Digitalis purpurea (foxglove).<br />
Leaves <strong>of</strong> this plant have several active and<br />
toxic glucosides: digitoxin, digitalin, digitonin. The<br />
poisons have a cumulative effect when ingest<strong>ed</strong>. Digitoxin<br />
was us<strong>ed</strong> in m<strong>ed</strong>icine to treat congestive heart<br />
failure and heart rhythm irregularities. It enhances and<br />
strengthens the force <strong>of</strong> the heart’s contractions. However,<br />
there are serious side effects; so usage is now out<br />
<strong>of</strong> favor in m<strong>ed</strong>ical practice.<br />
Linaria vulgaris Butter-and-eggs,<br />
Common Toadflax<br />
Numerous, narrow leaves (a) arise on the stem (b) <strong>of</strong><br />
this wild perennial. P<strong>ed</strong>uncles (c) have bracts (d) below<br />
the p<strong>ed</strong>icel (e). The flower’s sepal tube (f) has 5 lobes.<br />
115<br />
The bilabiate petals consist <strong>of</strong> an upper petal lip (g)<br />
with 2 lobes and a lower petal lip (h) with 3 lobes and a<br />
conspicuous elevat<strong>ed</strong> palate (a projection which closes<br />
the throat, i). Extending from the lower lip is a nectarcollecting<br />
spur (j).<br />
With the 2 petal lips cut apart, the 2 long (k) and 2<br />
short (l) stamens can be seen surrounding the pistil. The<br />
pistil has an ovary (m) consisting <strong>of</strong> 2 carpels containing<br />
numerous ovules (n) and a single style (o) and stigma<br />
(p). A nectar disc (q) surrounds the ovary base.<br />
A nectar-seeking bee separates the lips, slides its head<br />
between the rows <strong>of</strong> hairs on the palate (i), inadvertently<br />
transfers pollen to the stigma, sucks nectar from the<br />
spur, and is dust<strong>ed</strong> with pollen from the anthers as it<br />
departs.<br />
Castilleja coccinea Indian Paint-brush<br />
As a saprophyte, annual plants are <strong>of</strong>ten found in a<br />
circle above buri<strong>ed</strong> organic material. The leaves (s) below<br />
flowers are 3-part<strong>ed</strong>, bract-like and variable in form.<br />
Bright r<strong>ed</strong> bracts (u, v) surround the flower (t). This plant<br />
is commonly seen in meadows and ravines in mountainous<br />
regions.<br />
Verbascum thapsus Mullein<br />
Mullein is a biennial plant that forms a rosette <strong>of</strong> leaves<br />
the first year, and in the second year, a tall, stout stem<br />
(w) with alternate leaves (x), topp<strong>ed</strong> by a spike <strong>of</strong> yellow<br />
flowers (y, z).<br />
COLOR CODE<br />
green: leaves (a, s, x), stem (b, w), p<strong>ed</strong>uncle<br />
(c), bract (d), p<strong>ed</strong>icel (e), sepals (f, z),<br />
disc (q)<br />
pale yellow: petal lips (g, h), spur (j)<br />
yellow-orange: palate (i)<br />
yellow: anthers (k), flowers (y)<br />
white: filament (l), style (o), ovules (n)<br />
r<strong>ed</strong>-purple: stem (r)<br />
pale green: ovary (m), stigma (p), flower (t),<br />
bract, shad<strong>ed</strong> area (u)<br />
r<strong>ed</strong>: bract, unshad<strong>ed</strong> area (v)
Gesneria Family (Gesneriaceae)<br />
This family is compos<strong>ed</strong> <strong>of</strong> mainly tropical plants. It includes<br />
herbs, shrubs, trees, vines, and epiphytes. In<br />
cool climates, the family is known for the ornamental<br />
houseplants such as African violets, cape primroses,<br />
and gloxinias. There are 125 genera with about<br />
2,000 species.<br />
The generally hairy leaves are usually opposite or occur<br />
in basal rosettes. Bisexual flowers arise in clusters<br />
or singly and have 5 sepals, 5 petals, 2 to usually 4<br />
stamens, and a single pistil. The ovary has 2 carpels<br />
fus<strong>ed</strong> into one chamber containing numerous ovules in<br />
parietal placentation. The position <strong>of</strong> the ovary may<br />
be superior, half-inferior, or interior. A nectar disc is under<br />
the ovary or nectar glands surround the ovary. A<br />
capsule is the usual fruit type.<br />
Aeschynanthus lobbianus Lipstick Plant,<br />
Blushwort<br />
Because <strong>of</strong> its trailing stems (a) with bright r<strong>ed</strong> flowers,<br />
this Indonesian plant can be attractively display<strong>ed</strong><br />
in a hanging container. The fleshy leaves (b, c) are opposite<br />
and have smooth (entire) margins. Borne along<br />
the stem in leaf axils, the flower clusters have leaf-like<br />
bracts (d) at the base. Five hairy fus<strong>ed</strong> sepals (f) form<br />
a tube.<br />
116<br />
The flower developmental series shown reveals why<br />
Aeschynanthus is commonly call<strong>ed</strong> lipstick plant. As the<br />
flower develops, fus<strong>ed</strong> r<strong>ed</strong> petals (g) rise out <strong>of</strong> the sepal<br />
tube. The bilabiate (two-lipp<strong>ed</strong>) petals open into 2 upper<br />
and 3 lower lobes with darkly color<strong>ed</strong> nectar guide<br />
markings (h), which attract bird pollinators. Protruding<br />
from the upper petal lobes are 4 anthers (i).<br />
Four stamen filaments (j) arise from the petals and join<br />
to form 2 pairs <strong>of</strong> anthers (i, k). Inside the petal tube,<br />
the pistil has an inferior ovary (l), a single stigma, and<br />
a style (m), which is surround<strong>ed</strong> at the base by nectar<br />
glands (n).<br />
Saintpaulia ionantha African Violet<br />
From Africa, but not a true violet (Viola, see 92), this<br />
plant forms a basal rosette <strong>of</strong> hairy leaves (o) with scallop<strong>ed</strong><br />
margins. Clusters <strong>of</strong> flowers range in color from<br />
white to pink to blue to purple, depending on the variety<br />
and hybrid cultivar.<br />
Basically, the flower consists <strong>of</strong> 5 sepals (q) and 5 petals<br />
(r), but extra petal-like structures (s), form<strong>ed</strong> from stamens,<br />
may be present. The 2 functional stamens each<br />
have 2 anther sacs (t, v) and a wide filament (w). The<br />
pistil (x) has a superior ovary (y) cover<strong>ed</strong> with glandular<br />
hairs, and a style (z), which extends at an angle.<br />
COLOR CODE<br />
gray-green: stem (a), p<strong>ed</strong>icel (e), leaves (o)<br />
green: leaf upper surface (b)<br />
light green: leaf underside (c), style (m),<br />
ovary (l, y), nectar glands (n),<br />
pistil (x, z)<br />
dark purple-r<strong>ed</strong>: bracts (d), sepal tube (f),<br />
petal markings (h), anthers (i, k)<br />
r<strong>ed</strong>: petals (g)<br />
white: filaments (j, w)<br />
brown: p<strong>ed</strong>icel (p), sepals (q)<br />
purple: petals (r), staminodes (s), petal and<br />
staminode base (u)<br />
yellow: anthers (t, v)
Honeysuckle Family (Caprifoliaceae)<br />
Distinguishing features <strong>of</strong> this family include opposite,<br />
simple leaves without stipules. Flowers are usually<br />
bisexual and <strong>of</strong>ten in pairs. The stamens arise from<br />
the petals (epipetalous) and alternate with the petal<br />
lobes.<br />
The pistil’s ovary is inferior with 3–5 carpels. There is<br />
usually one ovule in each locule. The single style has<br />
stigmas equal in number to the carpels. Fruit types are<br />
berries or drupes and highly desir<strong>ed</strong> by birds. Plants in<br />
this family are mostly woody shrubs and vines. Many<br />
members make wonderful landscaping plants. There<br />
are about 18 genera and about 450 species.<br />
Of interest...ornamentals: Abelia × grandiflora (glossy<br />
abelia), Linnaea borealis (twinflower), Leycesteria,<br />
Lonicera × heckrottii (goldflame honeysuckle), Symphoricarpos<br />
(snowberry, coralberry), Viburnum acerifolium<br />
(mapleleaf viburnum), V. carlesii (Korean spice<br />
viburnum, and its fragrant hybrids: V. × burkwoodii,<br />
V. × carlcephalum, V. × juddii), V. cassinoides (witherod<br />
viburnum), V. dentatum (arrow-wood, so nam<strong>ed</strong> for<br />
its straight stems formerly us<strong>ed</strong> by Native Americans<br />
for making arrows), V. lentago (nannyberry, sheepberry),<br />
V. nudum (possum haw viburnum), V. prunifolium<br />
(black haw), V. × rhytidophylloides (leatherleaf<br />
viburnum), V. opulus variety americanum (formerly<br />
V. trilobum, American cranberry bush; it has <strong>ed</strong>ible,<br />
astringent fruit, delicious when made into a jelly), V.<br />
rufidulum (rusty black haw), Weigela; wild: Sambucus<br />
117<br />
canadensis (elderberry, the fruit is us<strong>ed</strong> in jelly, pie, and<br />
wine making).<br />
Lonicera japonica Japanese Honeysuckle<br />
This honeysuckle is a woody, climbing vine. Once cultivat<strong>ed</strong><br />
in the U.S., this species has become widely distribut<strong>ed</strong>,<br />
displacing native plants, and is now regard<strong>ed</strong><br />
as a noxious we<strong>ed</strong>.<br />
The hairy stems (a) have opposite, simple leaves (b)<br />
with short petioles (c). A pair <strong>of</strong> bisexual flowers is borne<br />
on a short p<strong>ed</strong>uncle (d). At the base <strong>of</strong> each flower pair<br />
is a pair <strong>of</strong> leafy bracts (e). An individual flower has a<br />
tiny sepal cup (f) with even smaller bractlets (g) on each<br />
side. The petal tube (h) is divid<strong>ed</strong> into a four-lob<strong>ed</strong> lip<br />
and a one-lob<strong>ed</strong> lip. Five stamens (i) protrude from the<br />
long petal tube.<br />
The cut-open petal tube shows that the stamens arise<br />
from the top <strong>of</strong> the petal tube. The stamen’s filament<br />
(j) is attach<strong>ed</strong> to the center <strong>of</strong> the anther (k), providing<br />
for flexible movement. Extending from the nectar-fill<strong>ed</strong><br />
petal tube is the pistil’s long, slender style (l) and stigma<br />
(m). Pollination is by moths, which are attract<strong>ed</strong> to this<br />
highly scent<strong>ed</strong>, long-petal tube flower.<br />
A cross-section <strong>of</strong> the berry (n) fruit shows that the pistil’s<br />
inferior ovary is compos<strong>ed</strong> <strong>of</strong> 3 fus<strong>ed</strong> carpels (o).<br />
Pair<strong>ed</strong> berries develop from the pair<strong>ed</strong> flowers.<br />
COLOR CODE<br />
pale green: stem (a), style (l), stigma (m)<br />
green: leaves (b), petioles (c),<br />
p<strong>ed</strong>uncle (d), bracts (e), sepals<br />
(f), bractlets (g)<br />
pale yellow-orange: petals (h)<br />
white: stamens (i), filaments (j),<br />
anthers (k)<br />
black: berry (n)
Teasel Family (Dipsacaceae)<br />
There are only 11 general with 350 species in this small<br />
family <strong>of</strong> usually annual, biennial, or perennial herbs.<br />
The leaves are opposite.<br />
Bisexual flowers develop in a dense cone-shape head<br />
or on a spike. Individual flowers are surround<strong>ed</strong> at the<br />
base by a bract. Small sepals are join<strong>ed</strong> into a cupshape<br />
or divid<strong>ed</strong> into 5–10 hairy or bristle-like segments.<br />
Petals are unit<strong>ed</strong> into a tube with 4 or 2 stamens<br />
attach<strong>ed</strong>. The single pistil’s inferior ovary has one<br />
locule. The fertiliz<strong>ed</strong> ovule develops into an achene fruit.<br />
Dipsacus sylvestris Teasel<br />
Teasel is a tall, biennial herb that grows in low, wet areas<br />
along roadsides and in old fields. Its ridg<strong>ed</strong> stems (a),<br />
cover<strong>ed</strong> with spines, have narrow, opposite leaves (b)<br />
without petioles (sessile). Below the compact flower<br />
head are long, upward-curv<strong>ed</strong> bracts (c). A narrow,<br />
point<strong>ed</strong> bract (d) at the base <strong>of</strong> each flower (e) lends<br />
a pincushion appearance to the flower head.<br />
An enlarg<strong>ed</strong> single flower shows its enclosing bract (d),<br />
the silky-hair<strong>ed</strong> sepal cup (f), and white petal tube (g),<br />
which divides into 4 purple, overlapping lobes (h). Four<br />
stamens (i), insert<strong>ed</strong> in the petal tube, emerge free at<br />
the top. Pollen (j) is sh<strong>ed</strong> inwardly toward the stigma (k).<br />
With the petal tube and inferior ovary (l) cut open, the<br />
pistil’s style (m) and ovule (n) can be seen. The fertiliz<strong>ed</strong><br />
ovule develops into an achene (o) fruit.<br />
Of interest...ornamental: The dry cone-like heads (inflorescence)<br />
at maturity are collect<strong>ed</strong> for use in dri<strong>ed</strong><br />
flower arrangements; utility: The dry cone-like heads<br />
with their bristle-like segments can be us<strong>ed</strong> to “card’<br />
wool (like a comb) to remove extraneous matter from<br />
the wool.<br />
118<br />
COLOR CODE<br />
light green: stem (a)<br />
green: leaves (b), bracts (c), sepal cup (f)<br />
white: petal tube (g), pollen (j), stigma (k),<br />
ovary (l), style (m), ovule (n)<br />
lavender: bract (d), flowers (e), petal lobes (h),<br />
stamens (i)<br />
tan: achene (o)
Aster Family (Asteraceae)<br />
Asteraceae represents the largest dicot family, with<br />
about 25,000 species distribut<strong>ed</strong> worldwide. It includes<br />
herbs, shrubs, trees, epiphytes, vines, and succulents.<br />
Leaves show an extreme range <strong>of</strong> diversification, with<br />
an alternate, opposite, or whorl<strong>ed</strong> arrangement. The<br />
blades are simple to compound, lob<strong>ed</strong>, ne<strong>ed</strong>le-like, or<br />
scale-like.<br />
If a flower looks like a daisy, it is probably in the aster<br />
family. The common characteristic in this family is the<br />
head <strong>of</strong> many modifi<strong>ed</strong> flowers (a composite <strong>of</strong> flowers).<br />
What appears to be a flower is actually a multiple<br />
false flower. There is an almost complete loss<br />
<strong>of</strong> sepals (calyx). Another characteristic includes having<br />
fus<strong>ed</strong> anthers forming a cylinder around the style<br />
(syngenesious condition). As the stigma and style<br />
grows up through the cylinder, it pushes the anthers<br />
out so as to facilitate pollen dispersal. This prevents<br />
self-fertilization.<br />
The flower’s single pistil has an inferior ovary compos<strong>ed</strong><br />
<strong>of</strong> 2 carpels fus<strong>ed</strong> to form one chamber with one ovule<br />
that matures into an achene fruit without endosperm.<br />
Some <strong>of</strong> the flower modifications are shown with the<br />
two illustrat<strong>ed</strong> plants.<br />
Of interest...food: Artemisia dracunculus (tarragon),<br />
Carthamnus tinctorius (safflower), Chichorium endivia<br />
(endive), C. intybus (chicory), Cynara scolymus<br />
(artichoke), Guizotia abyssinica (niger se<strong>ed</strong>),<br />
Helianthus tuberosus (Jerusalem artichoke), H. annuus<br />
(sunflower se<strong>ed</strong>s, oil), Lactuca sativa (lettuce);<br />
m<strong>ed</strong>icinal: Artemisia annua (sweet wormwood, source<br />
<strong>of</strong> artemisinin, an anti-malaria drug); ornamentals:<br />
Ageratum, Aster, Calendula, Dahlia, Dendranthema<br />
(chrysanthemum), Echinops (globe thistle), Gaillardia,<br />
Gazania, Gerbera, Helianthus (sunflower), Helichrysum<br />
(strawflower), Leontopodium (<strong>ed</strong>elweiss), Leucanthemum<br />
(daisy), Liatris (blazing star), Solidago<br />
(goldenrod, an attractive fall-flowering addition to the<br />
garden, height varies with the cultivar and flowers attract<br />
many beneficial insects, commonly assum<strong>ed</strong> that this<br />
insect-pollinat<strong>ed</strong> plant is the culprit that causes hayfever<br />
when the blame goes to wind-pollinat<strong>ed</strong> plants such<br />
as Ambrosia, ragwe<strong>ed</strong>), Stokesia, Tagetes (marigold),<br />
Zinnia; insecticide: Tanacetum coccineum (pyrethrum,<br />
paint<strong>ed</strong> daisy); we<strong>ed</strong>s: Ambrosia (ragwe<strong>ed</strong>), Cirsium<br />
(thistle), Sonchus (sow-thistle), Taraxacum (dandelion),<br />
Xanthium spinosum (cocklebur), a se<strong>ed</strong>head with tiny<br />
hooklike spines on the surface clings to animal fur to<br />
119<br />
facilitate se<strong>ed</strong> dispersal. George de Mestral invent<strong>ed</strong><br />
a fastener combining the hooks like those <strong>of</strong> the cocklebur<br />
se<strong>ed</strong> head and loops like the fabric <strong>of</strong> his burr<strong>ed</strong><br />
pants. He call<strong>ed</strong> it “Velcro,” combining the words velour<br />
and crochet; poisonous pasture plants: Eupatorium<br />
rugosum (white snakeroot), Helenium (sneezewe<strong>ed</strong>),<br />
Senecio (ragwort).<br />
Rudbeckia hirta Black-Ey<strong>ed</strong> Susan, Coneflower<br />
This plant is a biennial or short-liv<strong>ed</strong> perennial herb. The<br />
habit drawing shows its leaves (a) <strong>of</strong> variable shape and<br />
with some having petioles (b). Long p<strong>ed</strong>uncles (c) support<br />
flower heads compos<strong>ed</strong> <strong>of</strong> yellow, sterile, ray flowers<br />
(d) which surround a cone <strong>of</strong> brown-petal<strong>ed</strong>, fertile<br />
disc flowers (e). Hairy bracts (f) below the flower head<br />
can be seen in the vertical section drawing. Many small<br />
disc flowers (e) are borne on a conical receptacle (g).<br />
Evolutionary modifications <strong>of</strong> Asteraceae flowers include<br />
sepals that are r<strong>ed</strong>uc<strong>ed</strong> to bracts (h) and petals<br />
(i) that are fus<strong>ed</strong> to form a tube <strong>of</strong> 5 lobes. Stamen<br />
modifications include filaments (j), <strong>of</strong> the 5 stamens, attach<strong>ed</strong><br />
inside the petal tube and lance-shap<strong>ed</strong> anthers<br />
(k) join<strong>ed</strong> to form a cylinder. After pollen is sh<strong>ed</strong>, the<br />
stigma (l) rises through the cylinder. This prevents selffertilization.<br />
Below the double stigmas are the pistil’s<br />
style (m) and inferior ovary (n) with 1 ovule (o).<br />
Tagetes patula Marigold<br />
A marigold flower head is support<strong>ed</strong> by a p<strong>ed</strong>uncle (p)<br />
and has fus<strong>ed</strong> bracts (q) below the head. Outer ray<br />
flowers (r) are, mainly, unisexually female, while inner<br />
disc flowers (s) are bisexual. Both have bracts (t) and<br />
both have a pistil with a double stigma (u) and an ovary<br />
(v) below other flower parts. The bisexual disc flower,<br />
cut open, shows the pistil’s ovule (w) attach<strong>ed</strong> to the<br />
base <strong>of</strong> the ovary and the style (x) that rises through the<br />
cylinder <strong>of</strong> the stamens’ anthers (y) after pollen is sh<strong>ed</strong>.<br />
COLOR CODE<br />
green: leaves (a, b), p<strong>ed</strong>uncle (c, p), bracts (f, q)<br />
yellow: ray petals (d), anthers (k, y)<br />
brown: disc petals (e, i), bract (h)<br />
white: receptacle (g), filaments (j), ovule (o,w)<br />
light green: stigmas (l, u), style (m, x), ovary (n, v),<br />
orange: ray petals (r), disc petals (s)<br />
tan: bracts (t)
Water-plantain Family (Alismataceae)<br />
This primitive monocot family is compos<strong>ed</strong> <strong>of</strong> aquatic<br />
plants that are annual or perennial herbs. Parts <strong>of</strong> the<br />
bisexual or unisexual flower are arrang<strong>ed</strong> in whorls <strong>of</strong> 3<br />
sepals, 3 petals, and 3 to numerous stamens and pistils.<br />
A pistil’s ovary contains usually one ovule in basal<br />
placentation. The fruit is an achene. There are 14 genera<br />
and about 100 species.<br />
The basally sheathing leaves are either floating or have<br />
long petioles that rise above water level. Leaf blades are<br />
variable, linear to round, or the bases are arrowheadshap<strong>ed</strong><br />
(saggitate), or arrowhead-shap<strong>ed</strong> with narrow,<br />
basal lobes nearly at right angles (hastate condition).<br />
Of interest...depending on the point <strong>of</strong> view, these<br />
plants are waterwe<strong>ed</strong> pests and can be very common<br />
we<strong>ed</strong>s in rice (Oryza sativa) paddies or useful for<br />
ornamental pool gardens: Alisma plantago-aquatica<br />
(water plantain), Echinodorus (bur-head), Sagittaria<br />
(arrowhead); wildlife food: most genera.<br />
Saggittaria latifolia Wapato, Arrowhead<br />
Fibrous roots (a) anchor this perennial herb in the mud<br />
substrate <strong>of</strong> aquatic habitats. Older plants have swollen<br />
tubers at the ends <strong>of</strong> rhizomes (underground stems).<br />
The common name, wapato, was us<strong>ed</strong> by Native Americans<br />
for the <strong>ed</strong>ible tubers. The leaf’s sheathing petioles<br />
(b) vary in length with the water depth. Arrowheadshap<strong>ed</strong><br />
leaf blades (c) are narrow, as shown, to wide.<br />
The p<strong>ed</strong>uncle (d) <strong>of</strong> the raceme bears whorls <strong>of</strong> unisexual,<br />
male flowers (e) at the top and female flowers<br />
(f) below. Having male and female flowers on the same<br />
individual plant is term<strong>ed</strong> a monoecious condition.<br />
An enlargement <strong>of</strong> the male flower shows more clearly<br />
the bract (g) at the p<strong>ed</strong>icel (h) base. Both male and<br />
female flowers each have 3 persistent, green sepals (i)<br />
and 3 white petals (j), which are sh<strong>ed</strong> early.<br />
The male flower has 24 to 40 stamens (k) in whorls.<br />
Pollen is sh<strong>ed</strong> through slits on the anther sacs (l).<br />
Seen in a vertical section, the female flower has numerous,<br />
densely aggregat<strong>ed</strong> pistils (n) borne on the receptacle<br />
(o). Each pistil has a simple stigma (p), a short<br />
style (q), and one basal ovule (r) in the ovary (s). The<br />
fruits produc<strong>ed</strong> are numerous, flat achenes.<br />
120<br />
COLOR CODE<br />
white: roots (a), petals (j), filament (m),<br />
receptacle (o), ovule (r)<br />
r<strong>ed</strong>-green: petioles (b)<br />
green: blades (c), p<strong>ed</strong>uncle (d), bract (g),<br />
p<strong>ed</strong>icels (h), sepals (i), pistils (n),<br />
stigma (p), style (q), ovary (s)<br />
yellow: stamens (k), anther (l)
Spiderwort Family (Commelinaceae)<br />
These popular houseplants are annual or perennial<br />
herbs deriv<strong>ed</strong> from tropical and subtropical regions.<br />
Clos<strong>ed</strong> sheathing leaf petioles and flower parts in 3’s<br />
are common characteristics. There are 38 genera and<br />
about 600 species.<br />
The alternate succulent leaves have entire margins and<br />
parallel venation. Leaf-like bracts sometimes partially<br />
enclose the flower clusters. The bisexual flower can<br />
also occur singly. Parts <strong>of</strong> the flower include 3 sepals,<br />
3 petals, 6 stamens (or 3 stamens and 3 staminodes<br />
or one functional stamen), and a single pistil. The stamens’<br />
filaments <strong>of</strong>ten have hairs. The pistil has a superior<br />
ovary <strong>of</strong> 3 fus<strong>ed</strong> carpels, one style, and one stigma.<br />
There are no nectar glands. A loculicidal capsule is<br />
usually the fruit type.<br />
Of interest...ornamentals: Callisia (strip<strong>ed</strong> inch<br />
plant),Commelina(dayflower),Cyanotis,Dichorisandra,<br />
Gibasis (Tahitian bridal veil), Rhoeo discolor (Mosesin-the-bulrushes),<br />
Tinantia, Trandescantia spp. (spiderwort,<br />
wandering Jew, inch plant), Zebrina pendula<br />
(wandering Jew); biology: The staminal hairs <strong>of</strong><br />
Tradescantia (spiderwort) are commonly us<strong>ed</strong> in introductory<br />
plant biology labs to observe cytoplasmic<br />
streaming (cyclosis) under the microscope.<br />
121<br />
Gibasis geniculata Tahitian Bridal Veil<br />
The thin, trailing stems (a), small leaves (v, c, d), and<br />
tiny flower clusters (e) provide a delicate appearance<br />
to this plant. It is <strong>of</strong>ten display<strong>ed</strong> in hanging containers.<br />
Because <strong>of</strong> the sheathing leaf petioles (b), the<br />
stem has a joint<strong>ed</strong> appearance. The wavy-margin<strong>ed</strong>,<br />
alternate leaves are green above (c) and purple (d)<br />
below (due to the presence <strong>of</strong> anthocyanin r<strong>ed</strong>dishpurple<br />
pigment).<br />
Branching from the p<strong>ed</strong>uncle (f), p<strong>ed</strong>icels (g) support<br />
the flowers. The flower has three sepals (h), 3 petals<br />
(e), 6 stamens (i), and a single pistil (j). The stamen<br />
has tufts <strong>of</strong> hairs (k) on the filament (l) below the anther<br />
(m). The pistil consists <strong>of</strong> stigma (n), style (o), and a 3lob<strong>ed</strong>,<br />
superior ovary (p). Fleshy sepals (h) remain and<br />
enclose the capsule fruit.<br />
Zebrina pendula Wandering Jew<br />
This low, spreading succulent (fleshy) herb has purple<br />
(q) and silvery-green (r) strip<strong>ed</strong> leaf blades with<br />
hairy petioles (s) that sheath the stem (t). Zebrina<br />
is from the Latin for zebra, and refers to the strip<strong>ed</strong><br />
leaves.<br />
COLOR CODE<br />
green: stem (a, t), upper blade surface<br />
(c), p<strong>ed</strong>uncle (f), stripes (r),<br />
petioles (s)<br />
purple: petiole (b), lower blade surface<br />
(d), p<strong>ed</strong>icel (g), margin and<br />
center stripes (q), bract (u, v)<br />
white: petals (e), hairs (k), filament (l)<br />
light green: sepals (h), pistil (j), ovary (p)<br />
yellow: stamens (i), anther (m)<br />
dark pink-lavender: stigma (n), style (o), petals (w)
S<strong>ed</strong>ge Family (Cyperaceae)<br />
Distinguish<strong>ed</strong> from grasses, which have hollow, round<br />
stems, s<strong>ed</strong>ges have solid-pith<strong>ed</strong>, <strong>of</strong>ten 3-sid<strong>ed</strong> stems.<br />
Grasses have leaves arrang<strong>ed</strong> in two ranks, whereas<br />
s<strong>ed</strong>ge leaves usually emerge from a stem node in three<br />
directions (three-rank<strong>ed</strong>). As in grasses, each s<strong>ed</strong>ge<br />
leaf is organiz<strong>ed</strong> into a blade (lamina) and an enclosing<br />
sheath. One bract or scale subtends each flower. There<br />
are 100 genera and about 4,000 species.<br />
S<strong>ed</strong>ges are usually bog or marsh plants and grow in<br />
clumps or extend from creeping, underground, rhizomelike<br />
stems. Minute flowers are arrang<strong>ed</strong> in spikelets.<br />
Sepals and petals are r<strong>ed</strong>uc<strong>ed</strong> to bristles, hairs, or<br />
scales, or are absent. Usually there are 3 stamens and<br />
a single pistil with a superior ovary consisting <strong>of</strong> 2 to 3<br />
carpels fus<strong>ed</strong> to form one chamber with one ovule. The<br />
pistil’s style sometimes forms a beak on the achenetype<br />
fruit.<br />
Of interest...ancient usage: Cyperus papyrus (pith<br />
us<strong>ed</strong> to make paper), Cyperus spp. (mat grass, hay<br />
grass, ro<strong>of</strong> thatching), Eleocharis spp. (basket making),<br />
Scirpus spp. (bulrushes for basketwork, mats,<br />
chair seats); food: Eleocharis tuberosa (Chinese water<br />
chestnut tubers); water garden plants: Cyperus<br />
alternifolius (umbrella plant), Carex spp., Leiophylum<br />
spp., Scirpus spp.; cattle fodder: Carex spp. (s<strong>ed</strong>ges);<br />
wildlife food: most genera.<br />
122<br />
Cyperus strigosus Umbrella S<strong>ed</strong>ge<br />
This perennial s<strong>ed</strong>ge has a smooth, three-sid<strong>ed</strong> stem<br />
(a), leaves (b) at the base, and clusters <strong>of</strong> flower<br />
spike (c) subtend<strong>ed</strong> by leaf-like bracts (d). A ray (e) <strong>of</strong><br />
spikes has loosely arrang<strong>ed</strong>, linear spikelets (f). Older<br />
plants have a short, knotty rhizome-like underground<br />
stem.<br />
A spikelet consists <strong>of</strong> a double row <strong>of</strong> overlapping,<br />
bisexual flowers, each enclos<strong>ed</strong> by a flatten<strong>ed</strong> scale<br />
(g, h). In the flower enlargement (shown), 3 stamens<br />
have been sh<strong>ed</strong>. Remaining are a green-keel<strong>ed</strong> (g), flatten<strong>ed</strong><br />
scale with golden, translucent sides (h) and the<br />
pistil. The pistil consists <strong>of</strong> a 3-part<strong>ed</strong> style (i) and an<br />
ovary (j). The fruit that develops is a 3-angl<strong>ed</strong>, beakless<br />
achene (k).<br />
Carex hystericina Porcupine S<strong>ed</strong>ge<br />
Unisexual flowers are form<strong>ed</strong> on separate spikelets<br />
<strong>of</strong> this s<strong>ed</strong>ge. Both male (l) and female (m) spikelets<br />
have leaf-like bracts (n) below. The female pistil (o)<br />
is compos<strong>ed</strong> <strong>of</strong> a 3-branch<strong>ed</strong> style (p) and an ovary<br />
surround<strong>ed</strong> by a flask-shap<strong>ed</strong> sac, the perigynium (q),<br />
with a 2-tooth<strong>ed</strong> beak (r). A small scale (s) subtends<br />
the pistil. As in other s<strong>ed</strong>ges, an achene (t) fruit is<br />
form<strong>ed</strong>.<br />
COLOR CODE<br />
green: stem (a), leaves (b), bracts (d, n),<br />
rays (e), scale keel (g)<br />
gold-green: spikelets (f)<br />
gold: scale side (h) covering ovary (j)<br />
tan: style (i), achene (k, t), male spikelet (l)<br />
light green: female spikelet <strong>of</strong> pistils (m, o),<br />
perigynium (q, r), scale (s)<br />
brown: styles (p)
Grass Family (Poaceae)<br />
The grass flower is unlike any other plant family’s flowers.<br />
Within a spike (a), the flower unit is call<strong>ed</strong> a<br />
spikelet. An exaggerat<strong>ed</strong> separation <strong>of</strong> the structures<br />
is shown in the spikelet diagram. For reference, the diagram<br />
and the spikelet drawing <strong>of</strong> Secale cereale (rye)<br />
have the same letter for a describ<strong>ed</strong> structure.<br />
The primary axis <strong>of</strong> the spikelet is call<strong>ed</strong> the rachilla<br />
(b). At the base <strong>of</strong> the spikelet are two bracts call<strong>ed</strong><br />
first glume (c) and second glume (d). The next bracts<br />
are call<strong>ed</strong> lemmas (e) and may have a bristlelike appendage<br />
(awn, f). A s<strong>of</strong>t inner bract is call<strong>ed</strong> the palea<br />
(g). The remaining parts comprise a floret (h). Each<br />
spikelet may have one or more florets, which are unisexual<br />
or bisexual.<br />
There are no sepals or petals. Instead, there are 2 or 3<br />
lodicles (i). Lodicles enlarge with turgor pressure and<br />
cause the lemmas and palea to expand, exposing the<br />
stamens and/or stigmas at pollination time.<br />
Grasses are wind-pollinat<strong>ed</strong>. There are usually 3 stamens<br />
with freely moving (versatile) anthers (j) and a<br />
single pistil with 2, usually feathery, stigmas (k). The<br />
pistil’s ovary (l) is superior and contains one ovule. The<br />
fruit is usually a grain (caryopsis, m) or a berry in some<br />
bamboos.<br />
Grasses are annual or perennial herbs except for bamboo,<br />
which is woody at maturity. Roots (n) are fibrous<br />
and adventitious roots arise from stem nodes. The<br />
stems, call<strong>ed</strong> culms (o) are usually hollow and round<br />
with one leaf (p) to a node (q). Leaves are alternate in<br />
two rows (ranks = a so-call<strong>ed</strong> distichous arrangement)<br />
up the culm. The leaf consists <strong>of</strong> a blade (lamina, r)<br />
and a sheath (s), which encircles the culm (stem), and<br />
has parallel venation (t). Where the leaf blade diverges<br />
from the culm is <strong>of</strong>ten an appendage, the ligule (u), and<br />
sometimes, as in rice (Oryza sativa) two sickle-shap<strong>ed</strong><br />
auricles that clasp the sheath.<br />
Economically, Poaceae is the most important plant<br />
family. Of interest...food crops: Avena sativa (oats),<br />
Hordeum (barley), Oryza sativa (rice), Saccharum <strong>of</strong>ficinarum<br />
(sugarcane), Secale cereale (rye), Setaria<br />
italica (millet), Sorghum bicolor (sorghum), Triticum<br />
(wheat), Zea mays (corn); shelter: Bambusa (bamboo);<br />
fodder: Agrostis (bentgrass), Dactylis glomerata<br />
(orchard grass), Phleum (timothy), Setaria italica (foxtail<br />
grass), Sorghum, Zea; lawn turf: Agrostis (bent<br />
123<br />
grass), Cynodon dactylon (Bermuda grass), Festuca<br />
spp. (fescue grass), Poa (bluegrass), Stenotaphrum<br />
(St. Augustine grass), Zoysia (zoysia grass); industry:<br />
various grasses (insulation materials, newsprint, ethyl<br />
alcohol); decontamination: Molasses is made from refin<strong>ed</strong><br />
sugar deriv<strong>ed</strong> from sugarcane (Saccharum <strong>of</strong>ficinarum).<br />
Besides its culinary use, molasses spurs the<br />
growth <strong>of</strong> one type <strong>of</strong> bacteria that creates favorable<br />
growth conditions for other bacteria that digest contaminants<br />
in pollut<strong>ed</strong> groundwater.<br />
Parts <strong>of</strong> a Grain<br />
The Triticum (wheat) grain diagram shows the source <strong>of</strong><br />
vitamins, nutrients, and metabolites that we utilize (see<br />
also 40, corn grain). Wheat bran, compos<strong>ed</strong> <strong>of</strong> pericarp<br />
(v), se<strong>ed</strong> coat (w) and protein–rich aleurone layer<br />
(x), contains vitamin B complex (thiamine, rib<strong>of</strong>lavin,<br />
niacin, pyridoxine, pantothenic acid), cellulose, phosphorus,<br />
calcium, and iron. Endosperm (y) is process<strong>ed</strong><br />
into flour that contains mostly starch and some protein.<br />
Wheat germ refers to the embryo (z) and is a source <strong>of</strong><br />
vitamin B complex, vitamin E, vitamin A, protein, iron,<br />
fat, sodium, copper, zinc, magnesium, and phosphorus.<br />
Wild wheat was domesticat<strong>ed</strong> by humans about 10,000<br />
years ago. There are now about 22,000 cultivars. There<br />
are two main categories: hard wheat to make bread<br />
and s<strong>of</strong>t wheat to make pasta, pastry, crackers, cakes,<br />
cookies and cereal.<br />
Rice (Oryza sativa) is sold as either white or brown<br />
rice. White rice is “polish<strong>ed</strong>” with consequent removal <strong>of</strong><br />
the protein-rich aleurone layer outside the endosperm.<br />
Brown rice has the aleurone layer left intact and is nutritionally<br />
far better than starch-rich white rice.<br />
COLOR CODE<br />
yellow: spikes (a), glumes (c, d), anthers (j),<br />
pericarp (v)<br />
green: lemmas (e), leaves (p), leaf blade (r),<br />
leaf sheath (s), ligule (u)<br />
light green: palea (g), lodicle (i), stigmas (k),<br />
ovary (l), culm (o)<br />
tan: grain (m), roots (n), se<strong>ed</strong> coat (w)<br />
orange: aleurone layer (x)<br />
white: endosperm (y), embryo (z)
Arrowroot Family (Marantaceae)<br />
Arrowroot plants are tropical, perennial herbs with underground<br />
stems (rhizomes). Because <strong>of</strong> the flower<br />
structure, this family is consider<strong>ed</strong> to be the most advanc<strong>ed</strong><br />
in its order, the Zingiberales. Other families<br />
includ<strong>ed</strong> in the order are the bird-<strong>of</strong>-paradise family<br />
(Strelitziaceae), the banana family (Musaceae), the<br />
ginger family (Zingiberaceae), and the canna family<br />
(Cannaceae).<br />
In the arrowroot family, there are 30 genera and 350<br />
species. The flower is bisexual but the fertile male part<br />
has been r<strong>ed</strong>uc<strong>ed</strong> to one stamen, which consists <strong>of</strong> one<br />
anther sac. One to 5 sterile stamens (staminodes) are<br />
also present.<br />
The single pistil has an inferior ovary with 3 chambers,<br />
although by evolutionary r<strong>ed</strong>uction, only one ovule may<br />
be produc<strong>ed</strong>. The fruit is a loculicial capsule or berrylike,<br />
and the se<strong>ed</strong>s <strong>of</strong>ten have a fleshy covering (aril).<br />
The arrow root leaf is compos<strong>ed</strong> <strong>of</strong> a petiole with a<br />
sheath covering and a joint where the blade is attach<strong>ed</strong>.<br />
The joint is a pad-like swelling (pulvinus) that controls<br />
“sleep movements.” Within the pulvinus, the vascular<br />
tissue is group<strong>ed</strong> in the center, surround<strong>ed</strong> by sensor<br />
and flexor parenchyma cells, which can expand and<br />
contract. Leaves are alternate and 2-rank<strong>ed</strong>, emerging<br />
in one plane on opposite sides <strong>of</strong> the stem. Venation is<br />
pinnate from the midrib and parallel.<br />
Of Interest...food: Maranta arundinacea (West Indian<br />
arrowroot) cultivat<strong>ed</strong> for the starchy rhizome: ornamentals:<br />
Calathea mackoyana (peacock plant), Calanthea<br />
zebrina (zebra plant), Calathea ornata, Maranta leuconeura<br />
kerchoveana (prayer plant, r<strong>ed</strong>-spott<strong>ed</strong> arrowroot,<br />
rabbit tracks), Thalia dealbata (water canna).<br />
Maranta leuconeura massangeana Prayer Plant<br />
The common name, prayer plant, is deriv<strong>ed</strong> from the<br />
orientation <strong>of</strong> the leaves at dusk. During daylight the<br />
124<br />
leaves are in a horizontal position. As light fades at sunset,<br />
the leaves take a vertical position that appear like<br />
hands in prayer.<br />
This small herbaceous plant is cultivat<strong>ed</strong> primarily as a<br />
foliage-type houseplant for its brightly color<strong>ed</strong> leaves.<br />
The stem (a) has a sheath (b) at nodes and the leaf<br />
petiole has a wing<strong>ed</strong> sheath (c). Where the petiole joins<br />
the blade is a short, joint<strong>ed</strong> segment, a pulvinus (d),<br />
where blade movement occurs in response to light and<br />
dark (nyctinastic response).<br />
The blade coloring is unusual, consisting <strong>of</strong> r<strong>ed</strong> parallel<br />
lines (e) that follow the pinnate venation pattern, a band<br />
(f) <strong>of</strong> yellow-green on both sides <strong>of</strong> the midrib area, with<br />
the remaining blade area (g) a dark green. The lower<br />
blade surface (h) is purple-r<strong>ed</strong>. In bud (i), the leaves are<br />
roll<strong>ed</strong>.<br />
Tiny flower bud (j) clusters (panicles) havep<strong>ed</strong>icels<br />
(k) enclos<strong>ed</strong> by bracts (l) at the base. Each flower<br />
has 3 sepals (n), a fus<strong>ed</strong> petal tube consisting <strong>of</strong> 3<br />
lobes (o) and 3 petal-like staminodes (p). A fourth<br />
staminode (r), fus<strong>ed</strong> to the petal tube, extends from the<br />
color<strong>ed</strong> staminodes. It has one fertile anther sac (s) attach<strong>ed</strong><br />
to the side <strong>of</strong> a hood (r) that encloses the pistil’s<br />
stigma (t).<br />
With physical disturbance <strong>of</strong> the hood<strong>ed</strong> staminode covering,<br />
the stigma (t) springs free as the style (u) coils<br />
down to its fusion point (v) on the staminode. At the<br />
same time, the few large pollen grains are propell<strong>ed</strong><br />
from the anther sac. The pistil’s inferior ovary (s) is below<br />
the sepals.<br />
COLOR CODE<br />
green: petiole sheath (c), petiole pulvinus (d),<br />
p<strong>ed</strong>uncle (m)<br />
purple-green: stem sheath (b), bracts (l)<br />
r<strong>ed</strong>: vein lines (e)<br />
yellow-green: midrib band (f)<br />
dark green: stem (a), remaining blade area (g)<br />
purple: lower blade surface (h), leaf bud (i),<br />
shad<strong>ed</strong> area <strong>of</strong> staminodes (q)<br />
lavender: flower buds (j), staminodes (p)<br />
light green: p<strong>ed</strong>icel (k), sepals (n), ovary (w)<br />
white: petals (o), staminode hood (r),<br />
anther sac (s), stigma (t), style (u)
Palm Family (Arecaceae)<br />
Palms are second to the grasses (see 123) in economic<br />
importance. In the tropics, they may be a source <strong>of</strong> food,<br />
clothing, shelter, and fuel. The palms, numbering about<br />
3,500 species, mostly consist <strong>of</strong> trees. Shrubs and vines<br />
are also represent<strong>ed</strong>.<br />
Lodoicea maldivica has the world’s largest se<strong>ed</strong>, a<br />
“double coconut,” made up <strong>of</strong> a two-lob<strong>ed</strong> drupe.<br />
Raphia fainifera has the largest flowering plant leaf, up<br />
to twenty meters long.<br />
Palms have a single apical bud, call<strong>ed</strong> “heart <strong>of</strong> palm.”<br />
When it dies or is remov<strong>ed</strong>, the plant dies. Tree-like<br />
forms have an unbranch<strong>ed</strong> trunk with a terminal crown<br />
<strong>of</strong> leaves, commonly call<strong>ed</strong> “fronds,” which emerge one<br />
at a time from the apical bud. Lignin, deposit<strong>ed</strong> in cell<br />
walls <strong>of</strong> stem (trunk) tissues provides sturdiness. As<br />
monocotyl<strong>ed</strong>ons, palms have no vascular tissue in the<br />
stem; so there is no secondary growth (see monocot<br />
stem, 15).<br />
The leafy frond is made up a blade, a petiole, and<br />
a sheathing base. Blade types are: fan-shap<strong>ed</strong> with<br />
feather-like (pinnate) veins, as in Lodoicea (a); fanshap<strong>ed</strong><br />
with veins arising from one point (palmate), as<br />
in Sabal (b); feather-shap<strong>ed</strong> (pinnately compound),<br />
as in Chama<strong>ed</strong>orea (c); or feather-shap<strong>ed</strong>, twic<strong>ed</strong>ivid<strong>ed</strong><br />
(bipinnately compound) asinCaryota (see<br />
126).<br />
Regardless <strong>of</strong> shape, the young leaf (e) looks like a rod<br />
with a length-wise strip that peels down like a zipper, to<br />
free the one to many leaflets that unfold like a fan. The<br />
leaf petiole may be smooth or tooth<strong>ed</strong> on its margin.<br />
Small flowers are usually form<strong>ed</strong> in loose clusters,<br />
call<strong>ed</strong> panicles (f), which have one or more bracts at<br />
125<br />
the base. Commonly, the plants have separate male<br />
and female flowers (unisexual) on the same plant<br />
(monoecious), or on separate plants (dioecious),<br />
while others have flowers with both male and female<br />
parts within one flower (bisexual). Flower parts are usually<br />
in 3’s, being separate or fus<strong>ed</strong>. Flowers are wind-,<br />
insect- or self-pollinat<strong>ed</strong>.<br />
Usually the fruit has one se<strong>ed</strong> and is a berry or drupe<br />
type. The outside wall <strong>of</strong> the fruit can be fleshy, fibrous or<br />
leathery. Storage tissue (endospem) within the se<strong>ed</strong> is<br />
oily or fatty rather than starchy. In coconuts (Cocos nucifer),<br />
it is liquid encas<strong>ed</strong> within the solid coconut “meat”<br />
that makes up the solid part <strong>of</strong> the endosperm.<br />
Of interest...economic plants: Areca catechu (betel<br />
nut palm), Calamus and Caemonorops (rattan<br />
cane), Cocos nucifera (coconut palm), Copernicia (carnauba<br />
wax), Elaeis guineesis (oil palm), Metroxylon<br />
(sago palm), Phoenix dactylifera (date palm), Paphia<br />
pendunculata (raffia, us<strong>ed</strong> as twine to tie tall<br />
plants to supports); ornamentals: Arecastrum (queen<br />
palm), Arenga pinnata (sugar palm), Caryota mitis<br />
(fishtail palm), Chama<strong>ed</strong>orea elegans (parlor palm),<br />
Chamaerops (European fan palm), Chrysalidocarpus<br />
(Madagascar feather palm), Cocothrinax argentea<br />
(silver palm), Erythea spp. (Mexican fan palms),<br />
Howeia spp. (curly palm, sentry palm, flat palm),<br />
Jubaea spectabilis (coquitos palm), Livistona spp. (fan<br />
palms), Metroxylon (sago palm), Rhapidophyllum (ne<strong>ed</strong>le<br />
palm), Rhapis (lady palm), Roystonea regia (royal<br />
palm), Sabal palmetto (cabbage palmetto), Serenoa<br />
(saw-palmetto), Trachycarpus fortunei (Chinese windmill<br />
palm), Thrinax (peaberry palm), Washingtonia filifera<br />
(sentinel palm); food: heart-<strong>of</strong>-palm; building materials:<br />
large palm leaves are us<strong>ed</strong> as “thatch” on ro<strong>of</strong>s<br />
<strong>of</strong> houses/huts in the tropics.<br />
COLOR CODE<br />
yellow-green: leaf (a)<br />
green: leaf (b)<br />
dark green: leaf (c), stem (d), new leaf (e)<br />
orange: panicle (f)
Palm Family (continu<strong>ed</strong>)<br />
Sabal palmetto Cabbage Palmetto<br />
This palm is native to the coastal regions <strong>of</strong> southeast<br />
Unit<strong>ed</strong> States, the West Indies, and Venezuela. It may<br />
grow up to 21 meters high. The leaf (see 125) is fanshap<strong>ed</strong><br />
with palmate venation. Long stems <strong>of</strong> many<br />
panicles arise with the leaves. A single panicle (a) with<br />
small, white bisexual flowers (b) is shown. The flower<br />
is without a stem (sessile) and consists <strong>of</strong> 3 bracts (c)<br />
at the base, 3 fus<strong>ed</strong> sepals (d), 3 petals (e), 6 stamens<br />
(f), and a single pistil (g) with a superior ovary having 3<br />
fus<strong>ed</strong> carpels.<br />
Chama<strong>ed</strong>ora elegans Parlor Palm, Collina,<br />
Neathe Bella<br />
The parlor palm, native to South America, is <strong>of</strong>ten us<strong>ed</strong><br />
as a pott<strong>ed</strong> houseplant. The fronds (leaves, see 125)<br />
are feather-shap<strong>ed</strong>. Arising with the leaves at the crown<br />
are branch<strong>ed</strong> racemes (panicles, h) <strong>of</strong> flowers which<br />
develop into black drupes (i). Bracts (j) enclose the<br />
base <strong>of</strong> the panicle.<br />
Chama<strong>ed</strong>ora ernesti variety augusti<br />
Instead <strong>of</strong> a single trunk, like the parlor palm (see 125)<br />
this Mexican species has many leafy stems arising from<br />
a common base. The panicle (k) has many bracts (l)<br />
enclosing the base and only a few stalks <strong>of</strong> flowers (m).<br />
Caryota mitis Fishtail Palm<br />
Twice divid<strong>ed</strong> (bipinnately compound) leaves distinguish<br />
this palm. The sub-leaflets (n) are fishtail-like.<br />
Leaves emerge along the stem instead <strong>of</strong> in a crown at<br />
the top. Panicles <strong>of</strong> flowers also arise along the length<br />
<strong>of</strong> the trunk. Flowers mature into fruits (o, p) starting<br />
from the end <strong>of</strong> the stalk (q). The drupes drop <strong>of</strong>f as<br />
they mature.<br />
126<br />
COLOR CODE<br />
white: flowers (b), petals (e), pistil (g)<br />
green: panicle stalk (a), sub-leaflets (n),<br />
immature drupe (o)<br />
tan: bracts (c, j, l), stalk end, shad<strong>ed</strong> (q)<br />
light green: sepals (d), stalk, upper portion (r)<br />
orange: panicle stalks (h)<br />
black: drupe (i), mature drupe (p)<br />
dark green: panicle stalk (k)<br />
yellow: stamens (f), flowers (m)
Arum Family (Araceae)<br />
A unique characteristic <strong>of</strong> this family is the elaborate<br />
reproductive structure consisting <strong>of</strong> a fleshy spike <strong>of</strong><br />
flowers, the spadix, subtend<strong>ed</strong> by a leaf-like bract, the<br />
spathe. These mostly tropical and subtropical plants<br />
are usually terrestrial herbs growing on the forest floor.<br />
Because <strong>of</strong> their low-light tolerance, they are popular<br />
as houseplants in cool climates. Poisonous calcium oxalate<br />
crystals are present in plant tissues and there may<br />
be a milky sap (latex).<br />
The leaves are simple or compound, occur at the<br />
base or are alternate on the stem, and have petiole<br />
bases that sheath the stem. The small flowers on the<br />
spadix are bisexual or unisexual. The flowers have<br />
an odor <strong>of</strong> rotten flesh, which attracts fly pollinators<br />
(see 34). There are 1 to 6 stamens and a single pistil<br />
with one to many carpels. Sepals and petals that<br />
look alike (tepals) may be present. The fruit type is a<br />
berry. There are about 110 genera and about 2,000<br />
species.<br />
Of interest...ornamentals: Aglaonema (Chinese evergreen),<br />
Amorphophallus (voodoo lily), Anthurium<br />
(flamingo flower), Caladium (elephant’s-ear), Dieffenbachia<br />
(dumb-cane), Helicodicerus, Monstera deliciosa<br />
(Swiss-cheese plant, cut-leaf philodendron), Philodendron,<br />
Pistia (water lettuce), Scindapsis (pothos,<br />
devil’s-ivy), Spathiphyllum (flame plant), Zant<strong>ed</strong>eschia<br />
aethiopica (calla lily); food: Alocasia (taro), Colocasia<br />
(taro), Xanthosoma (tannia); native wild plants:<br />
Arisaema triphyllum (Jack-in-the-pulpit), Calla palustris<br />
(wild calla), Orontium (golden club), Peltandra (arrow<br />
arum), Symplocarpus foetidus (skunk cabbage,<br />
see 34).<br />
As skunk cabbage shoots develop in early spring<br />
in northern temperate regions, they melt the snow<br />
around each shoot. This heat is generat<strong>ed</strong> through high<br />
127<br />
respiration rates in the developing spadix, in sufficient<br />
amounts to melt the snow and ice.<br />
Spathiphyllum Flame Plant<br />
This perennial herb has simple leaf blades (a) with<br />
sheathing petioles (b). The spadix (c) <strong>of</strong> bisexual flowers<br />
is subtend<strong>ed</strong> by a white petal-like spathe (d). Each<br />
flower (e) has 6 tepals (f) enclosing 6 stamens. The anther<br />
(g) <strong>of</strong> the stamen is sh<strong>ed</strong> form a fleshy filament<br />
(h) after pollen is releas<strong>ed</strong>. The pistil (i) has a flatten<strong>ed</strong><br />
3-part stigma (j) with ovules (k) in basal placentation<br />
(see 28).<br />
Arisaema triphyllum Jack-in-the-pulpit<br />
This North American wild flower is a perennial herb that<br />
arises from a solid bulb-like structure (corm, see 12).<br />
The compound leaf blade (l) is divid<strong>ed</strong> into 3 leaflets<br />
(hence, triphyllum). The petiole (m) is enclos<strong>ed</strong> by a<br />
sheath (n) at the base. Plants with one compound leaf<br />
have male flowers on the spadix, while plants with two<br />
compound leaves have female flowers.<br />
This unusual plant has unisexual flowers on the same<br />
plant at different times. Young plants with one compound<br />
leaf have only male flowers at the base <strong>of</strong> the<br />
spadix. In subsequent years, two leaves develop from<br />
the corm, and in a developmental sex change, the<br />
spadix produces only female flowers. Energy is expend<strong>ed</strong><br />
in the production <strong>of</strong> fruit; so food produc<strong>ed</strong> in<br />
the leaves and translocat<strong>ed</strong> to the corm must be sufficient<br />
to assure that shoot and reproductive (flowering<br />
and fruiting) development occurs the following year.<br />
In autumn, on plants with female flowers, a cluster <strong>of</strong><br />
r<strong>ed</strong> berries (s) is reveal<strong>ed</strong> as the spathe and leaves (t)<br />
wither.<br />
COLOR CODE<br />
green: blades (a), petioles (b, m), leaflets (l),<br />
sheath (n)<br />
white: spadix (c), spathe (d), tepals (f), pistil (i),<br />
stigma (j), ovules (k), filaments (h)<br />
yellow: anthers (g)<br />
light green: outer spathe (o), spadix (q), p<strong>ed</strong>uncle (r)<br />
purple: inner spathe (p)<br />
r<strong>ed</strong>: berries (s)<br />
tan: p<strong>ed</strong>uncle (u), leaves (t)
Lily Family (Liliaceae)<br />
Lily flowers have 3 sepals and 3 petals that look alike<br />
(tepals), 6 stamens, and a single pistil with a superior<br />
ovary compos<strong>ed</strong> <strong>of</strong> 3 fus<strong>ed</strong> carpels. Fruit types are<br />
septicidal or loculicidal capsules or berries.<br />
This large family <strong>of</strong> about 250 genera and about 4,600<br />
species consists mostly <strong>of</strong> perennial herbs with narrow,<br />
parallel-vein<strong>ed</strong> leaves and underground storage organs<br />
such as rhizomes, bulbs, corms, or tubers. Some plants<br />
are evergreen succulents, as in Aloe and Haworthia or<br />
vines as in Smilax (see 16).<br />
Leaf characteristics vary greatly from basal and linear<br />
with parallel veins to cauline (growing on a stem), as<br />
shown in the illustration. Some have net (reticulate)venation<br />
(Trillium). Others have leaf-tip tendrils (Gloriosa).<br />
Asparagus leaves are scale-like.<br />
Of interest...food: Allium spp. (onion, shallot, leek,<br />
garlic, chives), Asparagus <strong>of</strong>ficinalis (asparagus);<br />
m<strong>ed</strong>icine: Aloe vera (sap from leaves is us<strong>ed</strong> to treat<br />
burns and relieve the pain <strong>of</strong> sunburn), Colchicum<br />
(colchicine), Urginea (r<strong>ed</strong> squill); ornamentals: Allium,<br />
Aloe, Asphodeline (Jacob’s rod), Agapanthus<br />
(lily-<strong>of</strong>-the-Nile), Calochortus, Colchicum autumnale<br />
(autumn crocus), Convallaria majalis (lily-<strong>of</strong>-the-valley),<br />
Eremurus (foxtail lily), Fritillaria, Gloriosa (gloriosa lily),<br />
Haworthia, Hemerocallis (daylily), Hosta (hosta),<br />
Hyacinthus (hyacinth), Kniph<strong>of</strong>ia (torch lily, r<strong>ed</strong>-hotpoker),<br />
Lilium spp. (lilies), Muscari (grape-hyacinth),<br />
Sansevieria (snake plant, bowstring-hemp, leopard<br />
lily), Scilla (squill), Smilax (greenbriar, see 16), Tulipa<br />
(tulip); native wild plants: Erythronium spp. (dogtooth<br />
violet, trout lily), Maianthemum (false lily-<strong>of</strong> the<br />
valley), Lilium, M<strong>ed</strong>eola virginiana (Indian cucumberroot),<br />
Polygonatum (Solomon’s seal), Smilacina spp.<br />
(false Solomon’s seal), Trillium spp., Uvularia (bellwort),<br />
128<br />
Veltheimia viridifolia); poisonous: Amianthemum<br />
(stagger-grass), Convallaria majalis (lily-<strong>of</strong>-the-valley),<br />
Ornithogalum umbellatum (star-<strong>of</strong>-Bethlehem), Veratrum<br />
(false hellebore), Zigadenus Nuttallii (death<br />
camas, poison camas, merryhearts).<br />
Lily is a confusing common name. Examples <strong>of</strong> a few<br />
plants that are call<strong>ed</strong> lilies include lilies (Lilium), and<br />
daylilies (Hemerocallis) in the lily family (Liliaceae).<br />
Then, there are waterlilies (Nymphaea) in the waterlily<br />
family (Nymphaeae, 79), peace lily (Spathiphyllum)<br />
in the arum Family (Araceae, 127), blackberry lily<br />
(Belamcanda chinensis) in the iris family (Iridaceae,<br />
129), and spider lilies (Lycoris spp.) in the amaryllis<br />
family (Amaryllidaceae).<br />
Lilium michiganense Michigan Lily<br />
This wild lily is a perennial herb that grows to two meters<br />
in height. It is native to the midwestern prairie region<br />
<strong>of</strong> the Unit<strong>ed</strong> States. Whorls <strong>of</strong> leaves (a) occur<br />
along the stem (b). At the top are flowers with 6 orange<br />
or, rarely, orange-r<strong>ed</strong>, recurv<strong>ed</strong> tepals (c) that arise on<br />
p<strong>ed</strong>uncles (d).<br />
The flower also has 6 stamens (e) with each filament<br />
(f) attach<strong>ed</strong> in the center <strong>of</strong> the anther (g), providing<br />
for free movement. The single pistil (h) has a superior<br />
ovary compos<strong>ed</strong> <strong>of</strong> 3 carpels (i) with numerous ovules<br />
(j) in axile placentation, a long style (k), and a 3-lob<strong>ed</strong><br />
stigma (l). Sweat bees, butterflies and hummingbirds<br />
are the pollinators.<br />
A loculicidal capsule (m) is form<strong>ed</strong> from the ovary.<br />
One <strong>of</strong> the 3 locules shows a stack <strong>of</strong> flat, wing<strong>ed</strong><br />
se<strong>ed</strong>s (n).<br />
COLOR CODE<br />
green: leaves (a), stem (b), p<strong>ed</strong>uncle (d),<br />
pistil (h)<br />
orange: tepals (c), anther (g)<br />
brown: stamens (e), capsule (m)<br />
light green: filament (f), style (k), stigma (l)<br />
white: carpels (i), ovules (j)<br />
tan: se<strong>ed</strong> (n)
Iris Family (Iridaceae)<br />
Plants are perennial herbs or subshrubs with underground<br />
storage organs <strong>of</strong> rhizomes, bulbs, or corms.<br />
The leaves sheath at the base, overlapping each<br />
other transversely to form a flat fan-like arrangement<br />
(equitant) unique to this family. Venation is parallel.<br />
The 3 sepals <strong>of</strong> flowers in this family are color<strong>ed</strong> and<br />
petal-like. They may differ in size, shape, and color from<br />
the 3 petals. The bisexual flower has 3 stamens and a<br />
single pistil with an inferior ovary compos<strong>ed</strong> <strong>of</strong> 3 fus<strong>ed</strong><br />
carpels. The fruit type is a loculicidal capsule. There<br />
are about 70 genera and about 1800 species.<br />
Of interest...ornamentals: Antholyza, Belamcanda<br />
chinensis (blackberry or Chinese lily), Crocus, Eustylis,<br />
Freesia, Gladiolus, Iris, Ixia, Moraea, Nemastylis, Neomarica,<br />
Sisyrinchium, Tigridia; commercial: Crocus<br />
sativus (saffron flavoring, saffron dye), Iris rhizomes<br />
(orris root).<br />
Iris germanica Flag, Beard<strong>ed</strong> Iris, German Iris<br />
Iris plants are perennial herbs with a rhizome (a) storage<br />
organ and adventitious roots (b). Sword-shape leaves<br />
(c) overlap at the base in a fan-like arrangement.<br />
Flower color is wide-ranging in cultivat<strong>ed</strong> hybrids. It<br />
varies from white, yellow, orange, blue, purple, r<strong>ed</strong>, pink,<br />
to tan and various bicolors. A pair <strong>of</strong> green bracts (d)<br />
occurs below the elaborate flower. Bracts cover a flower<br />
bud (e). The 3 petal-like sepals (f), “falls,” are beard<strong>ed</strong><br />
129<br />
with hairs (g). The 3 upright petals (h), “banners,” curve<br />
inward. Above each sepal is a stamen (j).<br />
In the flower structure drawing, an upright stamen made<br />
up <strong>of</strong> filament (k) and anther (l) can be discern<strong>ed</strong> clearly.<br />
Nectar glands (m) occur where the filament emerges<br />
from the sepal tube (f).<br />
Where is the pistil? The bulge below the sepal tube is an<br />
obviously inferior ovary (n) with indentations denoting<br />
the three fus<strong>ed</strong> carpels. In an ovary cross-section, each<br />
carpel (o) has a chamber (locule, p) with ovules (q) in<br />
axile placentation.<br />
In the flower structure drawing, only one portion remains<br />
unidentifi<strong>ed</strong>. What looks like a petal with crest<strong>ed</strong><br />
wings above is one <strong>of</strong> 3 styles (r) with a flap <strong>of</strong> tissue,<br />
the stigma (s).<br />
Pollination involves insects. When a bee (t, u) alights on<br />
the sepal, it is guid<strong>ed</strong> by the beard hairs and color markings<br />
to the nectar location. As it works its way through<br />
a tunnel between style (v, r) and sepal (f) to the nectar<br />
glands, pollen on its body from another flower is rubb<strong>ed</strong><br />
<strong>of</strong>f onto the stigma flap (w, s). Then, as the bee backs<br />
out <strong>of</strong> the flower, its hairs are dust<strong>ed</strong> with pollen that is<br />
sh<strong>ed</strong> outwardly from anther sacs ( j, l). At maturity, the<br />
sepals raise upward against the styles, closing <strong>of</strong>f the<br />
tunnels.<br />
The iris fruit is a loculicidal capsule (x) with se<strong>ed</strong>s.<br />
COLOR CODE<br />
tan: rhizome (a), roots (b), capsule (x)<br />
green: leaves (c), bracts (d), bud (e),<br />
p<strong>ed</strong>uncle (i)<br />
yellow: beard (g), bee’s thorax (t) and<br />
abdomen (u)<br />
optional: 1 color from text: sepals (f), petals (h),<br />
styles (r, v)<br />
white: stamen ( j), filament (k), anther (l), nectar<br />
glands (m), ovary (n), carpel (o), ovules<br />
(q), stigma (s, w)
Orchid Family (Orchidaceae)<br />
The orchid flower is so specializ<strong>ed</strong> that the illustrat<strong>ed</strong><br />
species is ne<strong>ed</strong><strong>ed</strong> for a description <strong>of</strong> its structures. In<br />
general, the flower is usually bisexual, has 3 sepals that<br />
may resemble the 3 petals in color and form, a column <strong>of</strong><br />
fus<strong>ed</strong> stamens and stigmas, and an inferior ovary compos<strong>ed</strong><br />
<strong>of</strong> 3 carpels. Flower colors and color patterns<br />
vary widely. Nectar, odor, and form <strong>of</strong> the flower attract<br />
pollinators (specific in many cases). The fruit is a capsule<br />
that contains very tiny se<strong>ed</strong>s. Since the endosperm<br />
aborts as se<strong>ed</strong>s mature, a mutualistic fungal relationship<br />
has evolv<strong>ed</strong> that provides a source <strong>of</strong> metabolites<br />
for se<strong>ed</strong> germination.<br />
The plants are generally leafy, sometimes leafless.<br />
Leaves are alternate, very rarely opposite, whorl<strong>ed</strong> or<br />
r<strong>ed</strong>uc<strong>ed</strong> to scales. They are simple, thicken<strong>ed</strong>, usually<br />
linear, strap-shap<strong>ed</strong> or round, and basally sheathing the<br />
stem. These perennial herbs are distribut<strong>ed</strong> worldwide<br />
and comprise the largest plant family, with an estimat<strong>ed</strong><br />
30,000 species. They are terrestrial and saprophytic,<br />
deriving nutrients from soil and dead organic matter.<br />
Or they are epiphytic, attach<strong>ed</strong> to the surface <strong>of</strong> another<br />
plant, where they obtain nutrients from the atmosphere<br />
and debris accumulations among the roots. Orchids<br />
have fungus-root (mycorrhizal) association.<br />
Nutrient storage organs may be swollen stems (pseudobulbs,<br />
see 16) or swollen root-stem tubers, which<br />
the Greeks call<strong>ed</strong> “orchis” for their testiculate appearance;<br />
hence, the orchid name. Roots <strong>of</strong> most epiphytes<br />
are cover<strong>ed</strong> with a layer <strong>of</strong> white-color<strong>ed</strong> dead corky<br />
cells call<strong>ed</strong> velamen. Habitats vary enormously from<br />
dry sand to acidic bogs and wet meadows, from temperate<br />
forest and mangrove swamps to tropical cloud<br />
forests. There is even an underground orchid, Thizanthella<br />
gardneri.<br />
Of interest...flavoring: Vanilla (vanilla extract from<br />
capsules, commonly call<strong>ed</strong> beans); wild: most wild orchids<br />
are consider<strong>ed</strong> to be endanger<strong>ed</strong> species and<br />
are legally protect<strong>ed</strong>. In the Unit<strong>ed</strong> States, there are<br />
about 62 native genera; ornamentals: Anagrecum,<br />
Brassavola nodosa (lady-<strong>of</strong>-the-night, nam<strong>ed</strong> for release<br />
<strong>of</strong> scent at night when moth pollinators will<br />
be attract<strong>ed</strong>), Brassia spp. (spider orchids), Cattleya,<br />
Cymbidium, Dendrobium, Epidendrum, Habenaria spp.<br />
(fring<strong>ed</strong> orchids), Laelia, Miltonia spp. (pansy orchids),<br />
Odontoglossum, Oncidium, Paphiop<strong>ed</strong>ilum spp. (lady’s<br />
slipper orchids), Phalaenopsis spp. (moth orchids),<br />
Stanhopea, and Vanda are a few examples. In the<br />
130<br />
quest for more exotic specimens, growers combine<br />
genera through plant bre<strong>ed</strong>ing to form multigeneric<br />
types. For example Sophrolaeliocattleya is a hybrid<br />
compos<strong>ed</strong> <strong>of</strong> Sophronitis, Laelia,and Cattleya, abbreviat<strong>ed</strong><br />
as Slc. Further tinkering has produc<strong>ed</strong> Slc. Jewel<br />
Box ‘Scheherazade,’ with Sophronitis coccinea, us<strong>ed</strong><br />
to produce r<strong>ed</strong> hybrids; Laelia is us<strong>ed</strong> to produce<br />
free flowering and a fleshy substance, and Cattleya is<br />
us<strong>ed</strong> to produce size and modify form <strong>of</strong> foliage and<br />
flower.<br />
Cattleya bowringiana<br />
This plant is a tropical perennial epiphyte. Pseudobulbs<br />
(a) provide nutrient storage. R<strong>ed</strong>uc<strong>ed</strong> leaves (b)<br />
cover the stem. Expand<strong>ed</strong> leaves (c) are alternate and<br />
strap-shap<strong>ed</strong>. A sheath (d) encloses the base <strong>of</strong> the<br />
p<strong>ed</strong>uncle (e). In this genus, the flower’s sepals (f) are<br />
strap-shap<strong>ed</strong>, whereas, the 3 petals (g) are ruffl<strong>ed</strong>.<br />
In orchids, the central petal, call<strong>ed</strong> a lip, is usually<br />
larger and highly modifi<strong>ed</strong>, sometimes occurring in quite<br />
bizarre forms. The lip encloses the column, resulting<br />
from a fusion <strong>of</strong> male and female parts. At the<br />
tip <strong>of</strong> the column is an anther cap (h) with 4 masses<br />
<strong>of</strong> pollen, call<strong>ed</strong> pollinia (i), tuck<strong>ed</strong> into 2 pocket-like<br />
structures. A pollinium has a sticky pollen sac (j) and<br />
a hook<strong>ed</strong> caudicle (k). The remaining end <strong>of</strong> the column<br />
is form<strong>ed</strong> by 3 fus<strong>ed</strong> fertile stigmas (l) with the end<br />
<strong>of</strong> the terminal stigma forming a sterile, sticky flap, the<br />
rostellum (m).<br />
An insect follows the nectar guides (n) in order to locate<br />
the nectar tube (o), dislodges the anther cap, and<br />
carries pollinia to another flower, where they stick to<br />
the rostellum. The 3-carpell<strong>ed</strong> ovary (p), surrounding<br />
the nectar tube, contains minute ovules. The remaining<br />
part <strong>of</strong> the column (q) is stamen-style tissue, and is<br />
therefore, bisexual. A capsule (r) fruit is form<strong>ed</strong>.<br />
COLOR CODE<br />
tan: pseudobulb (a), r<strong>ed</strong>uc<strong>ed</strong> leaves (b),<br />
wither<strong>ed</strong> petals (s)<br />
green: expand<strong>ed</strong> leaves (c), sheath (d),<br />
p<strong>ed</strong>uncle (e), capsule (r)<br />
pink-purple: sepals (f), petals (g)<br />
yellow: pollinia (i), pollen sac (j)<br />
white: anther cap (h), caudicle (k), stigmas (l),<br />
rostellum (m), nectar tube (o), ovary (p),<br />
column (q)<br />
purple: nectar guides (n)
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132
Glossary <strong>of</strong> Word Roots<br />
a not, without (acephala) gamet spouse, sex cell (gamete)<br />
ab away from (abscise) gamo union, marriage (oogamy)<br />
aleuron flour (aleurone) gen origin, birth (gene)<br />
andro male (androecium) genus race (genus)<br />
angio box, vessel (angiosperm geo earth (epigeous)<br />
sporangium) glab bald (glabrous)<br />
anth flower (perianth) gland secrectory spot (glandular)<br />
antheros flowery (antheridium) glut glue (glutinous)<br />
anti against (antipodal) gymn nak<strong>ed</strong> (gymnosperm)<br />
apertur opening, hole (triaperturate) gyn female (gynoecium)<br />
api tip, apex (apical) habitus condition, physique (habit)<br />
arche beginning (archegonium) hal salt (halophyte)<br />
asco sac (ascocarp) hemi half (hemiparasite)<br />
ate provid<strong>ed</strong> with, (perfoliate) hetero other, different (heterospory)<br />
form<strong>ed</strong> into hex six (hexagonal)<br />
auto self (autotrophic) holo entire (holoparasitic)<br />
basidio small base (basidiocarp) homo same, alike (homospory)<br />
bi two, double (biloba) hydro water (hydroponics)<br />
cap head (capitate) hyph web (hyphae)<br />
capill hair (capillitium) hypo below (hypogeous)<br />
carp fruit (schizocarp) idium diminutive ending (antheridium)<br />
caul stem (cauline) il diminutive ending (lentil)<br />
cephal head (acephala) infra below (infrar<strong>ed</strong>)<br />
chloro green (chlorophyll) inter between (intercalary)<br />
chrom color (chromosome) intra within (intracellular)<br />
cid cut, kill (septicidal) iso equal, homogenous (isogamy)<br />
circ circle (circinate) karyron nut, nucleus (eukaryote)<br />
cleisto clos<strong>ed</strong> (cleistothecium, lab lip (bilabiate)<br />
cleistogamous) lamel plate, layer (lamella)<br />
coll glue (collenchyma) lamin blade (Laminaria)<br />
coma hair (comose) lance lance, blade (lanceolate)<br />
cyan dark blue (anthocyanin) leuco white (leucocyte)<br />
cyst bladder, bag (pneumatocyst) lig strap, ribbon (ligulate)<br />
cyt cell (leucocyte) lith stone (Lithops)<br />
dendr tree (dendrite) loc a small place, cell (locule)<br />
dent tooth (dentate) ligne wood (lignin)<br />
derm skin (epidermis) logos discourse, study (ecology)<br />
di two, separate (dicot) macro large, long (macroscopic)<br />
dictyo net (Dictydium, mega large (megaspore)<br />
dictyosome) meiosis r<strong>ed</strong>uction (meiosis)<br />
dichotomos cut into two (dichotomous) meri part, segment, (mericarp,<br />
el diminutive ending (p<strong>ed</strong>icel) component meristem)<br />
endo inside (endocarp) meso middle (mesophyll)<br />
epi upon (epiphyte) micro small, tiny (microphyll)<br />
equinus horse (Equisetum, mitos thread (mitosis)<br />
equitant) mono one, single (monocot)<br />
erythr r<strong>ed</strong> (phycoerythrin) morph form, structure (dimorphic)<br />
eu true, good (eukaryote) myco fungus, mushroom (Basidiomycota)<br />
ex from, beyond (excise) myx slime (Myxomycota)<br />
exo outside (exocarp) nat born, borne (circinate)<br />
fer bearer (conifer) nom name (binomial)<br />
fil thread-like (filiform) ode like (phyllode)<br />
fissio splitting (fission) oec household (dioecious, ecology)<br />
flagellum whip (flagellum) oid like (rhizoid)<br />
flav yellow (rib<strong>of</strong>lavin) ol little (petiole)<br />
flor flower (inflorescence) orth straight (orthotropism)<br />
fol leaf (perfoliate) ostiol little door (ostiole)<br />
fungus mushroom (fungus) ov egg (ovule, ovary)<br />
funiculus a small cord (funiculus) paleo ancient (paleobotany)<br />
133
palm hand (palmate) septum partition, wall, (septate)<br />
palustr swamp (palustris) enclosure<br />
para beside (parasite) sessilis fit for sitting (sessile)<br />
pect comb (pectinate) soma body (somatic)<br />
p<strong>ed</strong>, pod foot, stalk (stylopodium, soros heap (sorus)<br />
p<strong>ed</strong>uncle) species kind (species)<br />
pelt shield (peltate) sperm se<strong>ed</strong> (angiosperm)<br />
per through, by means <strong>of</strong> (perfoliate) sphen w<strong>ed</strong>ge (sphenophyll)<br />
peri around (perianth) sporo se<strong>ed</strong>, spore (sporophyte)<br />
phellos cork (phelloderm) stell star (stellate)<br />
phil love (Philodendron) strobilos twist<strong>ed</strong> object, top, (strobilus)<br />
phloos bark (phloem) pinecone<br />
phore bearer (antheridophore) stoma mouth (stomate)<br />
phyle tribe (phylogenic) stroma cushion, mattress (stroma)<br />
phyll leaf (sporophyll) stylo pillar (stylopodium)<br />
phyco seawe<strong>ed</strong> (phycoerythrin) sub under, less than (subtropical)<br />
phyte plant (epiphyte, super, supar above, over (superior)<br />
phytoplankton) syn, sym together, with, at the (synergid)<br />
pinn feather (pinnate) same time<br />
plast thing mold<strong>ed</strong> (protoplast) taxis arrangement, order (taxonomy)<br />
ploid fold (polyploid) terra earth (terrestrial)<br />
plume feather (plumose, plumule) tetra four (tetraspore)<br />
pneum lung, air, gas (pneumatocyst) thall shoot (thallus)<br />
poly many, much (Polyporus) tri three (triaperturate)<br />
por small opening (pore, poricidal) trichom hair (trichome)<br />
prim first (primordial) trop bend (tropism)<br />
pro before (prophase) troph nourish, food (autotrophic)<br />
protiston the very first (Protista) tuber knob, swelling (tuberous)<br />
proto first, original (protoplast) ul little (pinnule)<br />
pseud false (pseudobulb) uni one (unisexual)<br />
psilos bare, mere (Psilotum) vor eat (insectivorous)<br />
pterid fern (Pteridophyta) xanthos yellow (xanthophyll)<br />
pyle gate (micropyle) xer dry (xerophyte)<br />
rad root (radicle) xylon wood (xylem)<br />
reticulum a small net (reticulate) zygo yoke, pair (zygote, zygospore)<br />
rhap ne<strong>ed</strong>le (Rhapidophyllum)<br />
rhiz root (mycorrhizae)<br />
rhodon rose color (Rhodophyta, Singular (Plural) Endings<br />
Rhododendron)<br />
ros rose (rosette) alga (algae)<br />
sagitt arrow (sagittate) mitochondrion (mitochondria)<br />
sapro rotten (saprophyte) nucleus (nuclei)<br />
schiz deeply divid<strong>ed</strong> (schizocarp) phytum (phyta)<br />
scis cut (abscise)<br />
sect cut (dissect)<br />
semi half (Semibegoniella)<br />
Metric Equivalents<br />
nanometer (nm) = 10 −9 meter<br />
1 micrometer (micron, µm) = 10 −6 meter<br />
1 millimeter (mm) = 0.001 meter, 0.04 inch<br />
1 centimeter (cm), 10 mm = 0.01 meter, 0.39 inch<br />
2.54 centimeters = 1 inch<br />
1 decimeter, 10 cm = 3.9 inches<br />
0.91 meter = 1 yard<br />
1 meter (m), 100 cm = 3.28 feet<br />
134
<strong>Index</strong><br />
Aaron’s-beard, 98<br />
Abies, 73<br />
Abrus precatorius, 100<br />
Absidia, 47<br />
Abutilon, 90<br />
Acacia, 23, 100<br />
Acalypha hispida, 103<br />
Acer<br />
ginnala, 105<br />
japonicum, 105<br />
macrophyllum, 105<br />
negundo, 35<br />
palmatum, 105<br />
platanoides, 105<br />
pseudoplatanus, 105<br />
saccharinum, 14, 38, 105<br />
saccharum, 26, 105<br />
Aceraceae (Maple Family), 35, 105<br />
Acetabularia, 58<br />
Achimenes, 116<br />
Achlya, 46<br />
Aconitum, 80<br />
Adder’s-tongue ferns, 67<br />
Adiantum, 67, 72<br />
Aegopodium, 109<br />
Aeschynanthus lobbianus, 116<br />
African violet, 116<br />
Agar, 20, 57<br />
Agaricus, 50<br />
Aglaonema, 127<br />
Agrostemma githago, 87<br />
Agrostis, 123<br />
Ajuga, 113<br />
Albizzia, 100<br />
Albugo, 46<br />
Alder, 35, 84<br />
Aleurites fordii, 103<br />
Alfalfa, 12, 100<br />
Algae (see also Plant Kingdom)<br />
Blue-green “Algae,” 4, 6, 24, 41, 44,<br />
54,70<br />
Brown Algae, 4, 41, 59, 60, 61<br />
Golden Algae, 41, 56<br />
Green Algae, 4, 41, 54, 58, 62<br />
R<strong>ed</strong> Algae, 4, 41, 57<br />
Yellow-green Algae, 41, 56<br />
Alisma, 120<br />
Alismataceae, 120<br />
Alismatidae, 75<br />
Allium (onion), 16, 49, 128<br />
Allomyces, 46<br />
Almond, 99<br />
Alnus, (alder), 35, 84<br />
Alocasia, 127<br />
Aloe, 128<br />
Althea rosea, 90<br />
Altingis, 81<br />
Alyssum, 75, 96<br />
Amanita, 50<br />
Ambrosia, 119<br />
American chestnut, 48, 83<br />
American elm, 38, 82<br />
Amianthemum, 128<br />
Amorphophallus, 127<br />
Amur maple, 105<br />
Anabaena, 44, 70<br />
Anacardiaceae, 106<br />
Anacardium occidentale, 106<br />
Anagrecum, 130<br />
Andreaea, 63<br />
Androm<strong>ed</strong>a glaucophylla, 97<br />
Anemone, 80<br />
Anemonella, 80<br />
Anethum graveolens, 26, 109<br />
Angelica, 109<br />
Angel’s trumpet, 111<br />
Angiosperms, 75<br />
Anise, 109<br />
Anthoceros, 63<br />
Anthriscus cerefolium, 109<br />
Anthurium, 75, 127<br />
Antigonon, 89<br />
Antirrhinum, 115<br />
Aphanomyces, 46<br />
Apiaceae, 109<br />
Apical dominance, 19<br />
Apium graveolens, 109<br />
Apple, 4, 16, 31, 39, 49, 75, 99<br />
Apricot, 99<br />
Aquilegia, 81<br />
Arabis, 96<br />
Araceae (Arum Family), 23, 34, 127<br />
Arachis, 100<br />
Araucaria, 73<br />
Arborvitae, 73<br />
Arbutus, 97<br />
Arctostaphylos uva-ursi, 97<br />
Arcyria, 45<br />
Areca catechu, 125<br />
Arecaceae, 125, 126<br />
Arecastrum, 125<br />
Arecidae, 75<br />
Arenaria, 87<br />
Arenga pinnata, 125<br />
Aril, 73, 102<br />
Arisaema triphyllum, 127<br />
Armillaria, 50<br />
Armoracia, 96<br />
Arrow arum, 127<br />
Arrowhead, 120<br />
Arrowroot, 124<br />
Arrowroot Family, 124<br />
Arrow-wood, 117<br />
Artemisia dracunculus, 119<br />
Artichoke, 119<br />
Artist’s fungus, 50<br />
Arum Family, 23, 34, 127<br />
Asclepiadaceae, 110<br />
Asclepias<br />
curassavica, 110<br />
syriaca, 38, 110<br />
tuberosa, 110<br />
Ash, 35, 99, 114<br />
Asparagus <strong>of</strong>ficinalis, 128<br />
Aspen, 50, 95<br />
Aspirgillus, 48<br />
Asplenium nidus, 67<br />
Aster, 19, 119<br />
Asteraceae, 119<br />
Aster Family, 119<br />
Asteridae, 75<br />
Asterionella, 56<br />
Astilbe, 98<br />
Astraeus, 53<br />
Astragalus, 100<br />
ATP (adenosine triphosphate), 24<br />
Atropa belladonna, 112<br />
Aubrieta, 96<br />
Aucuba, 101<br />
Auricularia, 49<br />
Aurinia saxatilis, 96<br />
Australian gum tree, 75<br />
Autotroph, 55, 58, 115<br />
Auxin, 19, 20<br />
Avena sativa (oat), 19, 20, 26, 49, 123<br />
Avocado, 78<br />
Azalea, 97<br />
Azolla, 44, 67, 70<br />
Baby’s-breath, 87<br />
Bacillariophyceae, 56<br />
Bacillus radicicola, 43<br />
Bacteria, 6, 12, 24, 25, 41, 42, 45<br />
Bald cypress, 73<br />
Balsam poplar, 95<br />
Bamboo, 123<br />
Bambusa, 123<br />
Banana Family, 124<br />
Banana shrub, 77<br />
Barberry, 23, 49<br />
Bark, 9, 10, 15<br />
Barley, 26, 49, 123<br />
Basil, 113<br />
Basket-<strong>of</strong>-gold, 96<br />
Bauhinia, 100<br />
Bay laurel, 78<br />
Bazzania, 63<br />
Bean, 12, 14, 40, 100<br />
Bearberry, 97<br />
Beauty-bush, 117<br />
Beebalm, 113<br />
Beech, 35, 52, 83<br />
Beech Family, 35, 83<br />
Beet, 2, 4, 12, 88<br />
Begonia, 12, 93<br />
Begoniaceae, 93<br />
Begonia Family, 93<br />
Begoniella, 93<br />
Beilschmi<strong>ed</strong>ia, 78<br />
Belamcanda, 129<br />
Bell morel, 48<br />
Bell pepper, 111<br />
Bells-<strong>of</strong>-Ireland, 113<br />
Bellwort, 128<br />
Berberis (barberry), 23, 49<br />
Bergamot, 113<br />
Bermuda grass, 123<br />
Beta (beet), 2, 4, 12, 88<br />
Betel nut palm, 125<br />
Betula<br />
papyrifera, 84<br />
pendula, 75, 84<br />
Betulaceae (Birch Family), 35, 84<br />
Biennial, 12, 26, 87, 109, 115, 118, 119<br />
Big leaf maple, 105<br />
135
Bindwe<strong>ed</strong>, 112<br />
Birch, 35, 52, 75, 85<br />
Birch Family, 35, 85<br />
Bird-<strong>of</strong>-paradise Family, 124<br />
Bird’s-nest fern, 67<br />
Bird’s-nest fungus, 53<br />
Bishop’s-cap, 98<br />
Bitter nightshade, 111<br />
Bittersweet, 102<br />
Blackberry, 99<br />
Blackberry lily, 129<br />
Black-ey<strong>ed</strong> Susan, 119<br />
Black locust, 38<br />
Black m<strong>ed</strong>ic, 38<br />
Black nightshade, 111<br />
Black oak, 39<br />
Black raspberry, 39, 99<br />
Bladderwort, 23<br />
Blood-flower, 110<br />
Blueberry, 97<br />
Bluegrass, 123<br />
Blue-green “Algae,” 4, 6, 24, 41, 44, 54,<br />
70<br />
Blue lace-flower, 109<br />
Blue milkwe<strong>ed</strong>, 110<br />
Blushwort, 116<br />
Bog rosemary, 97<br />
Boston fern, 67<br />
Boston ivy, 104<br />
Botrychium, 67<br />
Bougainvillea, 23<br />
Bouncing Bet, 87<br />
Bowstring-hemp, 20, 128<br />
Box elder, 35<br />
Bracken fern, 67<br />
Bract, 23, 29, 33, 34, 36, 38, 75, 77, 83,<br />
87, 93, 95, 101, 103, 109, 112,<br />
117, 118, 119, 122, 123, 124, 126,<br />
127, 129<br />
Brasenia, 79<br />
Brassavola, 130<br />
Brassia, 130<br />
Brassica, 38, 96<br />
Brassicaceae (Mustard Family), 38, 96<br />
Bridal wreath, 99<br />
British soldiers, 54<br />
Broccoli, 96<br />
Browallia, 111<br />
Brown Algae, 4, 41, 59, 60, 61<br />
Brussels sprouts, 96<br />
Bryophyte, 63<br />
Bucklandia, 81<br />
Buckwheat, 89<br />
Buckwheat Family, 89<br />
Bud<br />
axillary (lateral) bud, 14, 19<br />
flower bud, 29<br />
terminal bud, 14, 19, 25<br />
Bud scale, 14, 35, 82, 83<br />
Bud scale scar, 14<br />
Bugbane, 80<br />
Bugloss, 113<br />
Bulb, 8, 12, 16, 18, 128, 129<br />
Bull-bay, 77<br />
Bulrush, 122<br />
Bunchlberry, 101<br />
Bur-head, 120<br />
Burning bush, 102<br />
136<br />
Butter-and-eggs, 115<br />
Buttercup, 80<br />
Buttercup Family, 80<br />
Butterfly-we<strong>ed</strong>, 110<br />
Butterwort, 10, 23<br />
Cabbage, 97<br />
Cabbage palmetto, 125, 126<br />
Cabomba, 79<br />
Cactaceae, 4, 16, 85, 86<br />
Cactus Family, 4, 16, 85, 86<br />
Cafta, 102<br />
Caladium, 127<br />
Calamites, 43, 66<br />
Calamus, 125<br />
Calathea, 124<br />
Calceolaria, 115<br />
Calcium carbonate, 2, 63<br />
Calcium oxalate, 127<br />
California laurel, 78<br />
Calla lily, 127<br />
Calla palustris, 127<br />
Callirhoë, 90<br />
Callisia, 121<br />
Calodendrum, 107<br />
Calonyction aculeatum, 112<br />
Caltha, 80<br />
Calvatia, 53<br />
Caemonorops, 125<br />
Camphor, 78<br />
Camptosorus, 67<br />
Candy-tuft, 96<br />
Cannaceae,123<br />
Canna Family, 124<br />
Cantaloupe, 94<br />
Cape chestnut, 107<br />
Cape primrose, 116<br />
Capillitium, 45, 53<br />
Caprifoliaceae, 117<br />
Capsella bursa-pastoris, 96<br />
Capsicum, 111<br />
Caraway, 109<br />
Carbon dioxide, 24, 25, 43, 47<br />
Carbon fixation, 3, 24<br />
Carex hystericina, 122<br />
Carnation, 87<br />
Carnauba palm, 125<br />
Carnegiea gigantea, 36<br />
Carnivorous plants, 19, 23, 91<br />
Carrion-flower, 110<br />
Carrot, 4, 12, 38, 109<br />
Carrot Family, 109<br />
Carophyllaceae, 87<br />
Carum carvi, 109<br />
Caryophyllidae, 4, 75<br />
Caryota mitis, 125, 126<br />
Cashew, 106<br />
Cashew Family, 106<br />
Casparian strip, 13<br />
Cassia, 100<br />
Castanea, 83<br />
Castilleja coccinea, 115<br />
Castor-bean, 103<br />
Catha, 102<br />
Catnip, 113<br />
Cattail Family, 35<br />
Cattleya, 130<br />
Cauliflower, 96<br />
Cayenne pepper, 111<br />
C<strong>ed</strong>ar, 49, 73<br />
Celastraceae, 102<br />
Celery, 109<br />
Cell structure<br />
cell organelles, 2, 3, 7, 18, 41, 59<br />
amyloplast, 3, 13<br />
chloroplast, 2, 3, 10, 13, 22, 24, 55,<br />
56, 58, 59<br />
chromoplast, 2, 3<br />
dictyosome, 2, 3<br />
endoplasmic reticulum, 2, 3<br />
leucoplast, 2, 3<br />
mitochondrion, 2, 3<br />
nucleus, 2, 3, 5, 6, 7, 10, 30, 31, 32,<br />
37, 41, 44, 45, 58<br />
plastid, 2, 3, 41<br />
ribosome, 2, 3, 43<br />
vacuole, 2, 4, 5, 59<br />
cell wall, 2, 3, 5, 7, 8, 11, 13, 43, 44<br />
chromosome, see Chromosome<br />
cytoplasm, 2, 3, 5, 7, 8, 18, 24, 43, 58<br />
middle lamella, 2<br />
nucleoid, 6, 43<br />
nucleolus, 2, 7, 58<br />
plasma membrane, 2, 5,43<br />
pit field, 2, 8, 10, 11, 72<br />
protoplast, 2, 8, 43, 56<br />
Cell types<br />
antipodal cell, 32<br />
bulliform cell, 22<br />
collenchyma cell, 8<br />
companion cell, 8, 11<br />
cork cell, 9, 10, 15, 22<br />
egg cell, 27, 30, 32, 46, 56, 59, 60, 61,<br />
62, 63, 64, 66, 67, 71<br />
epidermal cell, 10, 13, 22<br />
eukaryotic cell, 2, 41, 42<br />
fiber cell, 8, 11, 22<br />
guard cell, 10, 22, 24<br />
laticifer, 11<br />
mother cell, 30, 31, 32<br />
parenchyma cell, 8, 11, 13, 22, 60, 124<br />
prokaryotic cell, 41, 43, 44<br />
sclereid (stone cell), 8, 11, 22<br />
sclerenchyma cell, 8, 22<br />
sex cell (gamete), 6, 30, 45, 46, 55, 57,<br />
59, 60, 61, 65<br />
sieve element, 11<br />
sieve cell, 8, 11<br />
sieve tube element, 8, 11, 18<br />
silica cell, 10, 22<br />
somatic (vegetative) cell, 6, 30<br />
subsidiary cell, 10, 22<br />
synergid cell, 32, 37<br />
tracheary element, 11<br />
tracheid, 8, 11, 17<br />
vessel element, 8, 11, 17<br />
Cellulose, 2, 8<br />
Celtis tenuifolia, 82<br />
Centaurea, 4<br />
Cephalaria, 118<br />
Cerastrium, 87<br />
Ceratium, 55<br />
Ceratocystis ulmi, 48, 82<br />
Cercis, 100<br />
Ceropegia woodii, 110<br />
Cetarias, 54
Chaetomium, 48<br />
Chamaecyparis, 73<br />
Chama<strong>ed</strong>orea, 125, 126<br />
Chamaerops, 125<br />
Chantharellus, 51<br />
Chara, 62<br />
Charophyta, 41, 62<br />
Cheeses, 90<br />
Chenille plant, 103<br />
Chenopodiaceae, 88<br />
Chenopodium, 26, 89<br />
Cherry, 39, 99<br />
Chervil, 109<br />
Chestnut, 35, 83<br />
Chestnut blight, 48, 83<br />
Chichorium, 119<br />
Chick pea, 100<br />
Chickwe<strong>ed</strong>, 87<br />
Chicory, 119<br />
Chinese anise, 77<br />
Chinese elm, 82<br />
Chinese evergreen, 127<br />
Chinese lantern, 111<br />
Chinese water chestnut, 122<br />
Chinese windmill palm, 125<br />
Chionanthus, 114<br />
Chitin, 46<br />
Chives, 128<br />
Chlamydomonas, 58<br />
Chloroplast, 2, 3,10,13, 22, 24, 55, 56,<br />
58, 59<br />
Chlorophyll, 3, 4, 24, 47, 56, 57, 58, 59,<br />
62, 66<br />
chlorophyll a, 4, 24, 45, 55, 56, 57, 58,<br />
59, 62<br />
chlorophyll b, 4, 58, 62<br />
chlorophyll c, 4, 55, 56, 59<br />
chlorophyll d, 4, 57<br />
Choanephora, 47<br />
Chondrus, 57<br />
Christmas rose, 80<br />
Christmas vine, 112<br />
Chromosomes, 2, 6, 7, 30, 55<br />
crossing-over (chiasma), 6, 30<br />
diploid (2n), 6, 30, 37, 59, 61, 64, 67<br />
haploid (1n), 6, 30, 31, 37, 59, 61, 63,<br />
64, 67<br />
Chrysophyceae, 56<br />
Chysalidocarpus, 125<br />
Chysanthemum, 19, 26, 119<br />
Cibotium, 67<br />
Cicer, 100<br />
Cicuta maculata, 109<br />
Cimicifuga, 80<br />
Cinnamomum, 78<br />
Cinnamon, 78<br />
Cirsium, 119<br />
Cissus, 104<br />
Citron, 94, 107<br />
Citrullus lanatus, 94<br />
Citrus, 39, 107<br />
Cladonia, 54<br />
Cladophora, 58<br />
Clathrus, 53<br />
Claviceps, 48<br />
Clavulinopsis, 52<br />
Clematis, 16, 80<br />
Clover, 12, 26, 33, 100<br />
Clubmosses, 41, 42, 65<br />
Coccoloba uvifera, 89<br />
Cocklebur, 26, 119<br />
Coco-de-mer, 125<br />
Coconut palm, 125<br />
Cocothrinax argentea, 125<br />
Codiaeum, 103<br />
Colchicine, 128<br />
Colchicum, 128<br />
Coleus, 19, 113<br />
Collinea, 126<br />
Colocasia, 127<br />
Columbine, 80<br />
Columnea, 116<br />
Commelina, 121<br />
Commelinaceae, 121<br />
Commelinidae, 75<br />
Common blue violet, 92<br />
Common mallow, 90<br />
Common rue, 107<br />
Common toadflax, 115<br />
Cone, 38, 71, 73, 74<br />
Coneflower, 26, 119<br />
Conifer, 8, 9, 12, 13, 15, 21, 22, 33, 38,<br />
40, 41, 42, 50, 63, 71, 73, 76<br />
Conium maculatum, 109<br />
Convallaria majalis, 128<br />
Convolvulaceae, 112<br />
Convolvulus, 112<br />
Copernicia, 125<br />
Coprinus, 51<br />
Coquitos palm, 125<br />
Coral bells, 98<br />
Corallina, 57<br />
Coral plant, 115<br />
Coral-sumac, 106<br />
Cordaites, 42<br />
Coriander, 109<br />
Coriandrum sativum, 109<br />
Coriolus, 52<br />
Cork, 9, 10, 15, 22<br />
Cork tree, 107<br />
Corm, 12, 16, 18, 65, 128, 129<br />
Corn, 12, 19, 24, 40, 123<br />
Cornaceae, 101<br />
Corn cockle, 87<br />
Cornelian cherry, 101<br />
Cornflower, 4<br />
Cornus, 101<br />
Cortinarius, 50<br />
Corylopsis, 81<br />
Corylus, 84<br />
Coscinodiscus, 56<br />
Cotinus coggygria, 106<br />
Cotton, 10, 90<br />
Cottonwood, 95<br />
Cow cockle, 87<br />
Cow-parsnip, 109<br />
Cranberry, 97<br />
Crane’s-bill, 109<br />
Crataegus, 99<br />
Crocus, 16, 129<br />
Cronartium, 49<br />
Croton, 103<br />
Crown-<strong>of</strong>-thorns, 103<br />
Crucibulum, 53<br />
Cucumber, 39, 94<br />
Cucumber tree, 77<br />
Cucumis, 39, 94<br />
Cucurbita, 94<br />
Cucurbitaceae (Gourd Family), 39, 94<br />
Cumin, 109<br />
Cuminum cyminium, 109<br />
Cup-<strong>of</strong>-gold, 111<br />
Cupressus, 73<br />
Curl<strong>ed</strong> dock, 38<br />
Curl<strong>ed</strong> mallow, 90<br />
Curly palm, 125<br />
Currant, 98, 104<br />
Cuscuta, 112<br />
Cutin, 2,10,13, 22<br />
Cut-leaf philodendron, 127<br />
Cyanobacteria, 41, 44<br />
Cyanotis, 121<br />
Cyathus, 53<br />
Cycads, 41, 42, 44, 71, 72<br />
Cycadophyta, 41, 71<br />
Cydonia, 99<br />
Cylindrospermum, 44<br />
Cymbalaria, 115<br />
Cymbidium, 130<br />
Cynara scolymus, 119<br />
Cynodon, 123<br />
Cyperaceae, 122<br />
Cyperus, 122<br />
Cypress, 73<br />
Cypress spurge, 88<br />
Cypress vine, 112<br />
Cyrtomium, 67<br />
Cytokinin, 19<br />
Dacryopinax, 49<br />
Dactylis, 123<br />
Dahlia, 12, 119<br />
DaIdinia concentrica, 48<br />
Dandelion, 119<br />
Darlingtonia, 91<br />
Date palm, 125<br />
Datura, 111<br />
Daucus carota (carrot), 4, 12, 38, 109<br />
Dayflower, 121<br />
Day lily, 128<br />
Deadly nightshade, 111<br />
Dead man’s finger, 48<br />
Death camas, 128<br />
Delonix, 100<br />
Delphinium, 4,80<br />
Dendrobium, 130<br />
Deptford-pink, 87<br />
Destroying angel, 50<br />
Deuteromycota, 46<br />
Deutzia, 98<br />
Devil’s-ivy, 127<br />
Diachea, 45<br />
Dianthus, 75, 87<br />
Diatom, 4, 41, 56<br />
Diatrypella, 48<br />
Dichondra, 112<br />
Dichorisandra, 121<br />
Dicot (dicotyl<strong>ed</strong>on), 1, 9, 12, 13, 14, 15,<br />
19, 21, 22, 27, 31, 37, 74, 75,<br />
77–119<br />
Dictamnus, 107<br />
Dictydium, 45<br />
Dictyophora, 53<br />
Didymium, 45<br />
137
Dieffenbachia, 127<br />
Digitalis purpurea, 115<br />
Dill, 26, 109<br />
Dilleniidae, 75<br />
Dinobryon, 56<br />
Din<strong>of</strong>lagellates, 41, 55<br />
Dioecious condition, 28, 35, 60, 63, 71,<br />
72, 73, 74, 78, 95, 105<br />
Dionaea, 23<br />
Dioön <strong>ed</strong>ule, 71<br />
Dipsacaceae, 118<br />
Dipsacus, 118<br />
Dipteronia, 105<br />
Diseases <strong>of</strong> plants, 43, 46, 47, 48, 49, 82,<br />
83<br />
Dittany, 107<br />
DNA (deoxyribonucleic acid), 2, 3, 6, 7,<br />
24, 41, 43, 44<br />
Doctor gum, 106<br />
Dodder, 112<br />
Dogtooth lily, 128<br />
Dogwood Family, 101<br />
Douglas fir, 73<br />
Draba, 96<br />
Dracaena, 15<br />
Drosera, 23<br />
Drymaria pachyphyua, 87<br />
Dryopteris carthusiana (spinulosa), 68<br />
Duckwe<strong>ed</strong>, 75<br />
Dulse, 57<br />
Dumb-cane, 127<br />
Dusty miller, 87<br />
Dutch elm disease, 82<br />
Dwarf chinkapin oak, 83<br />
Dwarf hackberry, 82<br />
Dyer’s woad, 96<br />
Ear fungus, 49<br />
Earth star, 53<br />
Earth tongue, 48<br />
Echinodorus, 120<br />
Echinopsis, 85<br />
Ecosystem, 43, 44, 45, 54, 56, 57, 58, 59<br />
Ectocarpus, 59<br />
Edelweiss, 119<br />
Egg, 27, 30, 32, 37, 46, 56, 59, 60, 61,<br />
62, 63, 64, 66, 67, 71<br />
Elaeis guineesis, 125<br />
Elaeodendron, 102<br />
Elderberry, 117<br />
Eleocharis tuberosa, 122<br />
Elephant’s-ear, 127<br />
Elm, 35, 38, 82<br />
Elm Family, 35, 82<br />
Encyclia, 16<br />
Endiandra, 78<br />
Endive, 119<br />
Endothia parasitica, 48, 83<br />
English oak, 83<br />
Enzyme, 2, 3, 4, 10<br />
Eph<strong>ed</strong>ra, 74<br />
Epidendrum, 130<br />
Epiphyte, 16, 20, 59, 64, 67, 76, 130<br />
Episcia, 116<br />
Equisetum, 15,16, 20, 43, 66<br />
Ergot <strong>of</strong> rye, 48<br />
Erica, 97<br />
Ericaceae, 97<br />
138<br />
Erodium, 108<br />
Eryngium, 109<br />
Erythea, 125<br />
Erythronium, 128<br />
Eucalyptus, 75<br />
Eudorina, 58<br />
Euonymus, 102<br />
Eupatorium rugosum, 119<br />
Euphorbia, 23, 26,103<br />
Euphorbiaceae (Spurge Family), 16, 103<br />
European fan palm, 125<br />
European spindle-tree, 102<br />
European white birch, 84<br />
Evernias, 54<br />
Fabaceae (Pea Family), 34, 39, 100<br />
Fagaceae (Beech Family), 35, 83<br />
Fagopyrum, 89<br />
Fagus, 83<br />
Fairy ring mushroom, 50<br />
False cypress, 73<br />
False dragonhead, 113<br />
False goat’s-beard, 98<br />
False hellebore, 128<br />
False Iily-<strong>of</strong>-the-valley, 128<br />
False mallow, 90<br />
False sandalwood, 82<br />
False Solomon’s seal, 128<br />
Fan palm, 125<br />
Fanwort, 79<br />
Fennel, 109<br />
Ferns, 8, 41, 42, 44, 67, 68, 69, 70<br />
Fertilization, 27, 33, 34, 37, 62, 63, 64,<br />
65, 66, 67, 71<br />
Festuca, 123<br />
Festue grass, 123<br />
Figwort, 115<br />
Figwort Family, 115<br />
Filbert, 84<br />
Fir, 73, 76<br />
Firethorn, 99<br />
Fishtail palm, 125, 126<br />
Flag, 34, 129<br />
Flagellum, 43, 44, 45, 46, 55, 56, 57, 58,<br />
60, 61, 62, 63, 64, 65, 71<br />
Flamingo flower, 75, 127<br />
Flame plant, 127<br />
Flat palm, 125<br />
Flower arrangement (inflorescence), 19,<br />
27, 33, 35<br />
catkin (ament), 35, 75, 83, 95<br />
cyme, 84, 102, 108, 111<br />
fleshy spike (spadix), 34, 75, 127<br />
head (capitulum), 33, 75, 118, 119<br />
panicle, 106, 114,124,125, 126<br />
raceme, 96, 100, 120<br />
single (scapose), 80, 85, 87, 90, 91,<br />
92, 112<br />
spike, 88, 115, 122, 123<br />
umbel, 109, 110<br />
Flowering dogwood, 101<br />
Flowering maple, 90<br />
Flowering plants, 1, 30, 31, 33, 41, 75,<br />
77–130<br />
Flower structure, 27, 28, 33, 34<br />
androecium, 27<br />
calyx, 27, 34<br />
corolla, 27, 33<br />
gynoecium, 27<br />
nectaries, see Nectar<br />
perianth, 27, 75<br />
petals, 10, 27, 28, 29, 33, 34, 35, 36,<br />
75<br />
bilabiate, 34, 36, 113, 115, 116, 117<br />
cruciform, 96<br />
funnelform, 34, 112<br />
pistil (stigma, style, ovary), see Pistil<br />
structure<br />
placenta, 27, 28, 32, 111<br />
receptacle, 27, 29, 99, 120<br />
sepals, 27, 28, 29, 33, 35, 75<br />
stamen (anther, filament, connective),<br />
see Stamen structure<br />
staminoids, 78, 116, 124<br />
tepals, 1, 26, 27, 36, 76, 85, 86, 89, 93,<br />
127, 128<br />
Flower symmetry, 34, 75<br />
Flower types<br />
bisexual (perfect), 28, 33, 35, 36, 75,<br />
78, 79, 80, 81, 82, 86, 87, 88, 89,<br />
90, 91, 97, 99, 101, 102, 107, 108,<br />
114, 115, 117, 119, 121, 122, 123,<br />
124, 126, 127, 130<br />
complete, 28<br />
dicot, 27, 77–119<br />
incomplete, 28<br />
monocot, 27, 120–130<br />
unisexual (imperfect), 28, 33, 35, 75,<br />
83, 84, 93, 94, 95, 103, 104, 105,<br />
106, 119, 120, 125, 127<br />
Fly agaric, 50<br />
Fly amanita, 50<br />
Foeniculum vulgare, 109<br />
Fomes, 52<br />
Fool’s huckleberry, 97<br />
Forsythia, 114<br />
Fortunella, 107<br />
Fossils, 42<br />
Fothergilla, 81<br />
Foxglove, 115<br />
Foxtail grass, 123<br />
Fragaria (strawberry), 20, 26, 39, 99<br />
Fragrant olive, 114<br />
Fraxinella, 107<br />
Fraxinus, 99, 114<br />
Freesia, 129<br />
Fringe tree, 114<br />
Fritillaria, 128<br />
Fruiting body, 45, 46, 47, 48, 49, 50, 51,<br />
52, 53, 54<br />
aethalium, 45<br />
ascocarps:<br />
apothecium, 48, 54<br />
cleistothecium, 48<br />
perithecium, 48<br />
basidiocarps:<br />
bird’s-nest, 53<br />
coral, 50, 52<br />
earthstar, 53<br />
mushroom, 49, 50, 51<br />
puffball, 49, 53<br />
shelf, 49, 50, 52<br />
stinkhorn, 53<br />
tooth<strong>ed</strong>, 50, 52<br />
plasmodiocarp, 45<br />
sporangium, 45
Fruit (ovary wall) tissues, 38, 39<br />
endocarp, 39, 107<br />
exocarp, 39, 107<br />
mesocarp, 8, 39, 97, 107<br />
pericarp, 38, 39, 40, 94, 123<br />
Fruit types, 38, 39<br />
achene, 38, 39, 80, 89, 118, 119, 122<br />
berry, 39, 79, 86, 98, 104, 111, 117,<br />
127<br />
capsule, 38, 81, 87, 90, 92, 93, 95, 98,<br />
102, 108, 114, 121, 128, 129,<br />
130<br />
cypsela, 38<br />
drupe, 39, 78, 82, 97, 101, 106, 114,<br />
125, 126<br />
drupelet, 39<br />
follicle, 38, 77, 110<br />
grain (caryopsis), 3, 19, 38, 40, 48, 123<br />
hesperidium, 39, 107<br />
legume, 8, 38, 100<br />
loment, 38, 100<br />
mericarp, 38, 90, 109<br />
nut, 8, 38, 83<br />
nutlet, 38, 88, 97, 113<br />
pepo, 39, 94<br />
pome, 39, 99<br />
samara, 38, 82, 84, 105, 114<br />
schizocarp, 38, 90, 103, 109<br />
silicle, 38, 96<br />
silique, 38, 96<br />
Fuchsia, 4, 20, 36<br />
Fucus, 61<br />
Fullmoon maple, 105<br />
Fungi, 1, 12, 24, 41, 45, 46, 47, 48, 49,<br />
50, 51, 52, 53, 54, 64, 82, 83<br />
Fungi Kingdom<br />
Ascomycetes, 47, 48, 54, 82, 83<br />
Euascomycetidae (molds, wilts,<br />
blight, mildews), 48<br />
Hemiascomycetidae (yeast, peach<br />
leaf curl), 47<br />
Basidiomycetes, 49, 50, 51, 52, 53, 54<br />
Agaricales (gill, pore, coral, tooth<strong>ed</strong><br />
fungi), 50, 51, 52<br />
Auriculariales (jelly fungi), 49<br />
Dacrymycetales (jelly fungi), 49<br />
Lycoperdales (puffball fungi), 53<br />
Nidulariales (bird’s-nest fungi), 53<br />
Phallales (stinkhorn fungi), 53<br />
Tremellales (jelly fungi), 49<br />
Ur<strong>ed</strong>inales (rusts), 49<br />
Ustilaginales (smuts), 49<br />
Chytridiomycetes (chytrids & allies), 46<br />
Myxomycetes (slime molds), 45<br />
Oomycetes (water molds, downy<br />
mildews, white rusts), 46<br />
Zygomycetes (black bread mold &<br />
allies), 47<br />
Gaillardia, 119<br />
Galaxaura, 57<br />
Gametophyte, 31, 32, 40, 57, 59, 60, 61,<br />
63, 64, 65, 66, 67, 72<br />
Ganoderma, 50<br />
Garlic, 128<br />
Gas-plant, 107<br />
Gaultheria, 97<br />
Gaylussacia, 97<br />
Gazania, 119<br />
Geastrum, 53<br />
Gelidium, 57<br />
Geoglossum, 48<br />
Geologic time scale, 41, 42<br />
Geraniaceae, 108<br />
Geranium, 108<br />
Geranium, 4, 108<br />
Geranium Family, 108<br />
Gesneria Family, 116<br />
Gesneriaceae, 116<br />
Giant sequoia, 73<br />
Giant water lily, 79<br />
Gibasis geniculata, 121<br />
Ginger Family, 124<br />
Ginkgo, 16, 21, 41, 71, 72<br />
Ginkgophyta, 41, 42, 72<br />
Gladiolus, 16, 129<br />
Gl<strong>ed</strong>itsia, 100<br />
Gloetrichia, 44<br />
Gloiopeltis, 57<br />
Gloriosa, 128<br />
Gloriosa lily, 16, 128<br />
Gloxinia, 116<br />
Glycine, 100<br />
Gnetes, 41, 42, 71, 74<br />
Gnetophyta, 41, 74<br />
Gnetum, 74<br />
Golden Algae, 41, 56<br />
Golden bells, 114<br />
Golden-chain tree, 100<br />
Golden club, 127<br />
Goldenrod, 38, 119<br />
Golden seal, 80<br />
Goldfish plant, 116<br />
Gonyaulax, 55<br />
Gooseberry, 98<br />
Gossypium hirsutum, 90<br />
Gourd, 94<br />
Gourd Family, 39, 94<br />
Goutwe<strong>ed</strong>, 109<br />
Grape, 16, 39, 104<br />
Grape Family, 104<br />
Grapefern, 67<br />
Grapefruit, 107<br />
Grape-hyacinth, 128<br />
Grape ivy, 104<br />
Graphis, 54<br />
Grass Family, 10, 15, 19, 22, 23, 24, 35,<br />
38, 76, 122, 123, 125<br />
Green Algae, 4, 41, 54, 58, 62<br />
Green ash, 114<br />
Greenbriar, 16, 128<br />
Greenheart, 79<br />
Green violet, 92<br />
Grey dogwood, 102<br />
Griselinia, 102<br />
Ground cherry, 111<br />
Growth<br />
primary, 9, 13, 15<br />
secondary, 9, 12, 13, 14, 15, 65, 67, 71<br />
Growth movements, 20<br />
Growth rings, 15<br />
Gymnocladus, 100<br />
Gymnodinium, 55<br />
Gymnosperm, 41, 71, 72, 73, 74<br />
Gymnosporangium, 49<br />
Gymnosporia, 102<br />
Gypsophila, 87<br />
Gyromitra, 48<br />
Haberlea, 116<br />
Hackberry, 35, 82<br />
Hair (trichome), 8, 9, 10, 13, 17, 22, 23,<br />
44, 67, 70, 77, 81, 85, 86, 88, 90,<br />
91, 94, 95, 97, 98, 106, 111, 116,<br />
117, 129<br />
Hamamelidaceae, 81<br />
Hamamelidae, 75<br />
Hamamelis, 81<br />
Hapalosiphon, 44<br />
Haworthia, 128<br />
Hawthorn, 49, 99<br />
Hazelnut, 35, 84<br />
Heath, 97<br />
Heath Family, 97<br />
H<strong>ed</strong>era, 16<br />
H<strong>ed</strong>ge bindwe<strong>ed</strong>, 112<br />
Helenium, 119<br />
Heliamphora, 91<br />
Helianthus<br />
annuus, 19, 119<br />
tuberosus, 119<br />
Helichrysum, 119<br />
Helicodicerus, 127<br />
Helleborus, 80<br />
Helminthostachys, 67<br />
Helwingia, 101<br />
Helvella, 48<br />
Hemerocallis, 128<br />
Hemitrichia, 45<br />
Hemlock, 73, 109<br />
Hepatica, 80<br />
Heracleum, 109<br />
Hericium, 52<br />
Herpobasidium, 49<br />
Hesperis, 96<br />
Heterospory, 65, 70<br />
Heuchera sanguinea, 98<br />
Hevea brasiliensis, 103<br />
Hibiscus<br />
esculentus, 90<br />
rosa-sinensis, 29<br />
syriacus, 26<br />
Hillebrandia, 93<br />
Hoary cress, 96<br />
Holly fern, 67<br />
Hollyhock, 49, 90<br />
Hollyhock mallow, 90<br />
Homospory, 64, 65, 66<br />
Honesty, 38, 96<br />
Honey-dew melon, 94<br />
Honey locust, 100<br />
Honey mushroom, 50<br />
Honeysuckle, 117<br />
Honeysuckle Family, 117<br />
Hop-hornbeam, 84<br />
Hop tree, 107<br />
Hordeum vulgare, 26, 123<br />
Hormones, 19, 20, 24, 26<br />
Hornwort, 42, 63<br />
Horse-bush, 119<br />
Horse-radish, 96<br />
Horsetails, 41, 42, 66<br />
Hosta, 128<br />
Howeia, 125<br />
139
Hoya carnosa, 110<br />
Huckleberry, 97<br />
Huernia, 110<br />
Hyacinth, 128<br />
Hyacinthus, 128<br />
Hybanthus, 92<br />
Hybrid, 1, 6, 77<br />
Hydrangea, 98<br />
Hydrastis, 80<br />
Hypha, 12, 46, 47, 48, 50, 54<br />
Iberis, 96<br />
Illicium vernum, 77<br />
Inch plant, 121<br />
Indian paint-brush, 115<br />
Indian pipe, 97<br />
Ipomoea<br />
batatas, 12, 112<br />
pandurata, 12<br />
purpurea, 112<br />
tuberosa, 16, 112<br />
Iridaceae (Iris Family), 34, 129<br />
Iris, 16, 34, 129<br />
Iris Family, 34, 129<br />
Irpex, 52<br />
Irish moss, 57<br />
Ironwood, 35<br />
Isatis tinctoria, 96<br />
Isoetes, 65<br />
Ivy, 12, 16<br />
Ixia, 129<br />
Jack-in-the-pulpit, 127<br />
Japanese dogwood, 101<br />
Japanese honeysuckle, 117<br />
Japanese lacquer-tree, 106<br />
Japanese laurel, 101<br />
Jasmine, 114<br />
Jasminum, 114<br />
Jerusalem artichoke, 119<br />
Jerusalem-cherry, 111<br />
Jimson we<strong>ed</strong>, 111<br />
Jubaea spectabilis, 125<br />
Juncaceae, 35<br />
Juniper, 49, 73<br />
Juniperus (c<strong>ed</strong>ar, juniper), 49, 73<br />
Kale, 96<br />
Kalmia, 97<br />
Kapuka, 101<br />
Kelp, 15, 59, 60<br />
Kenilworth ivy, 115<br />
Kentucky c<strong>of</strong>fee tree, 100<br />
Kinnikinik, 97<br />
Kniph<strong>of</strong>ia, 128<br />
Knotwe<strong>ed</strong>, 89<br />
Kochia, 88<br />
Kohleria, 116<br />
Kohlrabi, 96<br />
Kolkwitzia, 117<br />
Kudzu vine, 100<br />
Kumquat, 107<br />
Laburnum, 100<br />
Lactuca sativa, 119<br />
Lady palm, 125<br />
Lady’s thumb, 89<br />
Laelia, 130<br />
140<br />
Lagenaria, 94<br />
Lambkill, 97<br />
Lamb’s quarters, 26, 88<br />
Lamiaceae (Mint Family), 34, 113<br />
Laminaria, 60<br />
Larch, 73<br />
Larkspur, 4, 80<br />
Larix, 73<br />
Latex, 11, 79, 103, 110, 112<br />
Lathyrus latifolia, 100<br />
Lauraceae, 78<br />
Laurel Family, 78<br />
Laurus nobilus, 78<br />
Lavandula, 113<br />
Lavatera, 90<br />
Lavender, 113<br />
Leaf arrangement<br />
alternate, 21, 72, 81, 88, 93, 95, 97,<br />
102, 104, 110, 112, 115, 121, 123,<br />
124<br />
decussate, 87<br />
equitant, 129<br />
opposite, 21, 74, 87, 102, 105, 113,<br />
114, 116, 117, 118<br />
spiral, 65, 71<br />
rosette, 63, 65, 91, 109, 116<br />
whorl<strong>ed</strong>, 21, 74, 128<br />
Leaf, blade margin<br />
entire, 77, 78, 101, 114, 116, 121<br />
lob<strong>ed</strong>, 67, 70, 72, 78, 79, 83, 90, 94,<br />
104, 108, 111, 120<br />
peltate, 79<br />
saw-tooth<strong>ed</strong> (serrate), 80, 82, 84<br />
scallop<strong>ed</strong> (crenate), 92<br />
tooth<strong>ed</strong> (dentate), 80, 83, 95, 99, 102,<br />
105<br />
Leaf, external structure, 21<br />
blade, 21, 23<br />
cuticle, 17, 22<br />
coleoptile, 20, 40<br />
leaflet (pinna, pinnule), 21, 23, 33, 67,<br />
68, 69, 70, 71, 80, 100, 106, 109,<br />
125, 126, 127<br />
petiole (stalk), 8, 14, 21, 22, 23, 68, 69,<br />
70, 71<br />
pulvinus, 100, 124<br />
sheath (petiole), 21, 66, 109, 120, 121,<br />
123, 124, 127, 129, 130<br />
stipule, 16, 23, 77, 84, 89, 90, 92, 93,<br />
99, 100, 102, 108<br />
Leaf persistence<br />
deciduous, 21, 72, 76<br />
evergreen, 21, 65, 68, 76<br />
Leaf types, 21, 23, 40<br />
bract, 23, 29, 33, 34, 36, 38, 75, 77,<br />
83, 87, 93, 95, 101, 103, 109, 112,<br />
117, 118, 119, 122, 123, 124, 126,<br />
129<br />
carnivorous leaf, 23<br />
conifer leaf, 15, 21, 22<br />
dicot leaf, 21, 37, 40, 77–119<br />
compound leaf, 21, 35, 67, 68, 69, 70,<br />
71, 100, 106, 109, 125, 126, 127<br />
fern leaf, 67, 68, 69, 70<br />
microphyll, 65<br />
megasporophyll, 65, 71<br />
microsporophyll, 65, 71<br />
sporophyll, 66, 71<br />
monocot leaf, 1, 21, 40, 120–130<br />
phyllode, 23<br />
plumule, 40<br />
scale leaf, 12, 16, 85<br />
se<strong>ed</strong> leaf (cotyl<strong>ed</strong>on), 1, 8, 37, 40, 72,<br />
75<br />
simple leaf, 21, 67, 77, 79, 81, 83,<br />
84, 85, 97, 101, 103, 107, 108,<br />
110, 111, 112, 113, 114, 117,<br />
130<br />
spathe, 23, 127<br />
spine, 23, 36, 85, 103<br />
succulent leaf, 23<br />
Leaf venation<br />
dichotomous, 21, 71, 72<br />
palmate, 21, 67, 90, 93, 94, 105, 108,<br />
125<br />
parallel, 21, 120, 121, 123, 128<br />
pinnate, 21, 67, 68, 125, 126<br />
Leatherleaf fern, 69<br />
Leatherleaf, 97<br />
Leek, 128<br />
Lemon, 39, 107<br />
Lens, 100<br />
Lentil, 100<br />
Leonotis, 113<br />
Leontopodium, 119<br />
Leopard lily, 128<br />
Lepidium, 96<br />
Lepidodendron, 43<br />
Letharia, 54<br />
Lettuce, 119<br />
Leucothoë, 97<br />
Levisticum <strong>of</strong>ficinale, 109<br />
Lichen, 44, 54, 76<br />
Light wavelength, 4, 34<br />
Lignin, 8, 10, 23, 125<br />
Ligustrum, 114<br />
Lilac, 14,114<br />
Liliaceae, 1, 15,128<br />
Lilidae, 75<br />
Liliopsida, 1, 75,120–130<br />
Lilium michiganense, 1, 38, 128<br />
Lily, 1, 38,128<br />
Lily-<strong>of</strong>-the-valley, 128<br />
Lily Family, 1, 15, 128<br />
Lime, 107<br />
Linaria vulgaris, 115<br />
Lindera benzoin, 78<br />
Linnaea borealis, 117<br />
Linnaeus, Carolus, 41<br />
Lion’s-ear, 113<br />
Lipstick plant, 116<br />
Liquidambar styraciflua, 81<br />
Liriodendron tulipifera, 77<br />
Lithocarpus, 83<br />
Lithops, 23<br />
Lithothamnium, 57<br />
Litsea, 78<br />
Liverwort, 41, 44, 63<br />
Living stones, 23<br />
Livistona, 125<br />
Lobularia maritima, 75, 96<br />
Locowe<strong>ed</strong>, 100<br />
Locule, 27, 31, 32<br />
Locust, 38, 100<br />
Lodoicea maldivica, 125<br />
Loganberry, 99
Lolium perenne, 26<br />
Lonicera, 117<br />
Lo<strong>of</strong>ah, 94<br />
Loropetalum, 81<br />
Lousewort, 115<br />
Lovage, 109<br />
Luffa cylindria, 94<br />
Lunaria annua, 38, 96<br />
Lupine, 100<br />
Lupinus, 100<br />
Lychnis, 87<br />
Lycogala, 45<br />
Lycoperdon, 53<br />
Lycopersicon esculentum (tomato), 3, 4,<br />
111<br />
Lypodium, 65<br />
Lyonia mariana, 97<br />
Maclura pomifera, 39<br />
Madagascar featherpalm, 125<br />
Madagascar-jasmine, 110<br />
Magnolia, 75, 77<br />
Magnoliidae, 75<br />
Magnoliaceae, 77<br />
Magnolia Family, 77<br />
Magnoliophyta, 1, 75<br />
Magnoliopsida, 1, 75, 77–119<br />
Maianthemum, 128<br />
Maiden hair fern, 67, 72<br />
Maiden hair tree, 72<br />
Majorana, 113<br />
Mallow Family, 90<br />
Malope, 90<br />
Maltese cross, 87<br />
Malus (apple), 4, 16, 31, 39, 49, 75, 99<br />
Malvaceae, 90<br />
Malva, 90<br />
Mammillaria, 85, 86<br />
Mangifera indica, 106<br />
Mango, 106<br />
Mangrove, 12<br />
Manihot, 103<br />
Manroot, 12<br />
Maple, 26, 35, 38, 105<br />
Maple Family, 35, 105<br />
Maranta, 124<br />
Marantaceae, 124<br />
Marasmius, 50<br />
Marchantia, 63<br />
Marigold, 75, 119<br />
Marjoram, 113<br />
Marsilea quadrifolia, 70<br />
Marsh marigold, 80<br />
Mastic tree, 106<br />
Matthiola, 96<br />
Maytenus, 102<br />
Meadow rue, 80<br />
M<strong>ed</strong>icago, 12, 38, 100<br />
Meiosis, 30, 31, 32, 45, 46, 61, 63<br />
Melilotus, 100<br />
Melocactus, 85<br />
Melon, 94<br />
Mentha, 38, 113<br />
Menziesia ferruginea, 97<br />
Mercurialis, 103<br />
Mercury, 103<br />
Meristem, 9, 11, 13, 14, 15, 25, 40, 60,<br />
66, 69, 71, 74<br />
apical meristem, 9, 11, 13, 14, 15, 25,<br />
40<br />
cork cambium, 9, 13, 15<br />
ground meristem, 13, 15<br />
intercalary meristem, 15, 66, 74<br />
procambium, 9, 11, 13, 14, 15<br />
protoderm, 13, 15<br />
vascular cambium, 9, 13, 15<br />
Metopium toxiferum, 106<br />
Metroxylon, 125<br />
Mexican fan palm, 125<br />
Michelia fuscata, 77<br />
Michigan lily, 1, 38, 128<br />
Microasterias, 58<br />
Microglossum, 48<br />
Microsphaera, 48<br />
Milkwe<strong>ed</strong>, 38, 110<br />
Milkwe<strong>ed</strong> Family, 110<br />
Millet, 123<br />
Miltonia, 130<br />
Mimosa, 38, 100<br />
Mimulus, 115<br />
Miniature hollyhock, 90<br />
Mint, 38, 113<br />
Mint Family, 113<br />
Mitella, 98<br />
Mitosis, 7, 30, 31, 32, 45<br />
Mock orange, 98<br />
Molucella, 113<br />
Monarda, 113<br />
Money plant, 96<br />
Monera, 41<br />
Monilinia, 48<br />
Monkey-flower, 115<br />
Monkshood, 80<br />
Monocot (monocotyl<strong>ed</strong>on), 1, 9, 11, 12,<br />
13, 15, 21, 22, 27, 31, 35, 40, 75,<br />
120–130<br />
Monoecious condition, 28, 70, 73, 74, 83,<br />
84, 93, 94, 104<br />
Monotropa, 97<br />
Monstera deliciosa, 127<br />
Moonflower, 112<br />
Morel, 48<br />
Morchella, 48<br />
Morina, 118<br />
Morning glory, 112<br />
Morning Glory Family, 112<br />
Moses-in-the-cradle, 121<br />
Mosquito fern, 67, 70<br />
Moss, 41, 51, 63<br />
Mother-<strong>of</strong>-thousands, 98<br />
Moth orchid, 75<br />
Mountain ash, 99<br />
Mountain laurel, 97<br />
Mountain-rose vine, 89<br />
Mouse-ear chickwe<strong>ed</strong>, 87<br />
Mucor, 47<br />
Mullein, 115<br />
Murraya, 107<br />
Musaceae, 124<br />
Muscari, 128<br />
Musk mallow, 90<br />
Mustard, 38, 96<br />
Mustard Family, 38, 96<br />
Mutinus, 53<br />
Mutualist (symbiont), 12, 44, 46, 54, 55<br />
Mycelium, 46, 47, 48, 49<br />
Mycophycophyta, 54<br />
Mycorrhizae, 12, 46, 50, 64, 97, 130<br />
Myrrhis odorata, 109<br />
Myxomycetes, 45<br />
Nannyberry, 117<br />
Narcissus, 31<br />
Nasturtium, 96<br />
Neathe bella, 126<br />
Nectar, 33, 34, 36, 47, 99, 109, 115<br />
Nectar gland, disc, 8, 10, 23, 33, 34, 35,<br />
36, 75, 81, 94, 95, 96, 97, 101,<br />
103, 104, 106, 107, 108, 109, 112,<br />
115, 116, 129<br />
osmophor, 10<br />
Nectar guide, 33, 34, 92, 116, 130<br />
Nectar spur, 33, 34, 36, 92, 115<br />
Nectar tube, 33, 34, 130<br />
N<strong>ed</strong>dle palm, 125<br />
Nemopanthus, 116<br />
Neoporteria, 85<br />
Nepeta, 113<br />
Nephrolepis, 67<br />
Nereocystis, 60<br />
Neurospora, 48<br />
New Zealand spinach, 88<br />
Nicotiana, 34, 111<br />
Nidularia, 53<br />
Nierembergia, 111<br />
Nightshade Family, 111<br />
Ninebark, 99<br />
Nitrogen, 12, 23, 25, 43, 70, 100<br />
Nitrogen fixation, 12, 25, 43, 44, 100<br />
Nori, 57<br />
Norway maple, 105<br />
Nucleic acid, 24<br />
Nucleoid, 6, 43<br />
Nucleolus, 2, 7, 58<br />
Nucleoplasm, 2<br />
Nucleus, 2, 3, 5, 6, 7, 30, 31, 32, 37, 41,<br />
45, 58<br />
Nuphar, 79<br />
Nutrients, 25<br />
Nymphaeaceae, 79<br />
Nymphaea, 79<br />
Oak, 17, 35, 38<br />
Oats, 19, 20, 26, 49, 123<br />
Ochrolechia, 54<br />
Ocimum, 113<br />
Ocotea, 78<br />
Odontoglossum, 130<br />
Oil palm, 125<br />
Okra, 90<br />
Olea, 114<br />
Oleaceae, 114<br />
Olive, 114<br />
Olive Family, 99, 114<br />
Oncidium, 130<br />
Onion, 16, 49, 128<br />
Onoclea, 67<br />
Ophioglossum, 67<br />
Opuntia, 16, 85<br />
Orange jessamine, 107<br />
Orchard-grass, 123<br />
Orchid, 16, 75, 130<br />
Orchidaceae, 130<br />
Orchid Family, 130<br />
141
Orchid tree, 100<br />
Oregano, 113<br />
Oriental walnut, 78<br />
Origanum, 113<br />
Ornithogalum umbellatum, 128<br />
Orontium, 127<br />
Oryza sativa (rice), 3, 19, 26, 38, 70, 123<br />
Osage-orange, 39<br />
Osmanthus, 114<br />
Osmosis, 5,18<br />
Osmunda, 67<br />
Ostrya, 84<br />
Oswego tea, 113<br />
Otaheite gooseberry, 103<br />
Oxypetalum caeruleum, 110<br />
Oyster mushroom, 50<br />
Pachystima, 102<br />
Paeonia, 80<br />
Palm, 15, 25, 125<br />
Palmaria, 57<br />
Palm Family, 125, 126<br />
Pansy, 92<br />
Papaver, 38<br />
Paper birch, 84<br />
Paphiop<strong>ed</strong>ilum, 130<br />
Paprika, 111<br />
Parasite, 46, 47, 49, 54, 55, 112, 115<br />
Parlor palm, 125, 126<br />
Parmelia, 54<br />
Parsley, 109<br />
Parsnip, 109<br />
Parthenocissus<br />
quinquefolia, 16, 104<br />
tricuspidata, 104<br />
Pastinaca sativa, 109<br />
Pea, 12, 40, 100<br />
Peaberry palm, 125<br />
Peach, 99<br />
Pea Family, 34, 38, 100<br />
Peanut, 15, 100<br />
Pear, 8, 49, 99<br />
Peat moss, 63<br />
P<strong>ed</strong>icularis, 115<br />
Pelargonium, 4,108<br />
Peltandra, 127<br />
Penicillium, 48<br />
Penny cress, 96<br />
Pepper-grass, 96<br />
Perennial, 12, 14, 21, 64, 65, 66, 67, 68,<br />
79, 80, 86, 88, 91, 92, 93, 96, 98,<br />
100, 108, 110, 111, 112, 113, 115,<br />
120, 121, 122, 123, 124, 127, 128,<br />
129, 130<br />
Pereskia grandifolia, 85<br />
Persea, 78<br />
Petroselinum crispum, 109<br />
Petunia, 26, 111<br />
Phaeophyta, 41, 59, 60, 61<br />
Phalaenopsis, 75, 130<br />
Phallus, 53<br />
Phaseolus (bean), 12, 14, 40, 100<br />
Philadelphus, 98<br />
Philodendron, 16, 127<br />
Phleum, 123<br />
Phloem, 8, 9, 11, 13, 15, 17, 18, 22, 24,<br />
42<br />
Phoenix dactylifera, 125<br />
142<br />
Photosynthesis, 3, 4, 5, 8, 24, 40, 41, 44,<br />
60, 63, 85<br />
Phyllanthus, 103<br />
Phellodendron, 107<br />
Physalis, 111<br />
Physarum cinereum, 45<br />
Physcia, 54<br />
Physocarpus, 99<br />
Physoderma, 46<br />
Physostegia, 113<br />
Phytophthora infestans, 46<br />
Picea, 73<br />
Pieris, 97<br />
Pigments, 2, 3, 4, 24, 44<br />
accessory pigments, 4, 24, 44<br />
betalains, 4, 76, 87, 88<br />
betacyanin, 4, 75<br />
betaxanthin, 4, 75<br />
carotenoids, 3, 4, 10<br />
carotene, 4, 44, 55, 56, 57, 58, 59,<br />
62<br />
xanthophylls, 3, 4, 55, 57, 58, 62<br />
fucoxanthin, 4, 56, 59<br />
leutein, 4<br />
peridinin, 55<br />
violaxanthin, 4, 59<br />
zeaxanthin, 4<br />
chlorophylls, see Chlorophyll<br />
flavinoids, 4<br />
anthocyanin, 4, 25, 87<br />
flavin, 4<br />
rib<strong>of</strong>lavin, 4<br />
phycobilins, 4, 57<br />
phycocyanin, 4, 44, 57<br />
phycoerythrin, 4, 44, 57<br />
phytochrome, 4<br />
Pimpinella anisum, 109<br />
Pincushion cactus, 85, 86<br />
Pincushion flower, 118<br />
Pine, 41, 49, 73, 76<br />
Pinophyta, 41, 73<br />
Pinguicula, 10, 23<br />
Pink, 75, 87<br />
Pink Family, 87<br />
Pinnularia, 57<br />
Pinus, 40, 73<br />
Pistachio, 106<br />
Pistacia, 106<br />
Pistia, 126<br />
Pistil structure, 27, 28, 29, 32, 33, 37, 38,<br />
77–130<br />
carpel, 27, 28, 29, 32, 35, 38, 39, 75,<br />
79, 80, 92, 93, 94, 99, 101, 102,<br />
103, 105, 108, 109, 110, 111,<br />
112, 113, 114, 115, 121, 128,<br />
129<br />
ovary, 27, 28, 29, 32, 33, 35, 36, 37,<br />
38, 39, 75, 77, 78, 79, 82, 90, 92,<br />
93, 95, 97, 99, 101, 105, 109, 110,<br />
113, 114, 116, 118, 119<br />
ovary placentation, 27, 28, 32, 75<br />
axile, 28, 81, 91, 97, 114, 128, 129<br />
basal, 28, 75, 120, 127<br />
free-central, 28, 75, 87<br />
parietal, 28, 75, 86, 92, 94, 98, 100,<br />
110<br />
ovary position, 28, 33<br />
haif-inferior, 28, 81, 116<br />
inferior, 28, 33, 38, 39, 75, 84, 86,<br />
93, 94, 98, 99, 101, 109, 116, 117,<br />
118, 119, 124, 129, 130<br />
superior, 28, 29, 33, 38, 75, 77, 78,<br />
82, 87, 88, 90, 91, 96, 97, 100,<br />
102, 103, 104, 105, 107, 109, 111,<br />
112, 113, 114, 115, 116, 121, 122,<br />
123, 126, 128<br />
ovule, 27, 28, 29, 30, 32, 37, 40, 75,<br />
78, 79, 80, 86, 87, 90, 91, 92, 93,<br />
94, 95, 97, 98, 99, 100, 101, 106,<br />
109, 110, 111, 112, 114, 115, 118,<br />
119, 122, 123, 126, 129<br />
antipodal cells, 32<br />
egg, 27, 30, 32, 37<br />
embryo sac, 27, 30, 32, 37<br />
endosperm, 37, 40, 75, 123<br />
filiform apparatus, 32<br />
funiculus, 32, 40<br />
integument, 32, 37, 40, 75<br />
micropyle, 32, 37, 40<br />
nucellus, 32<br />
polar nuclei, 32, 37<br />
synergid cells, 32, 37<br />
stigma, 27, 29, 32, 33, 35, 36, 37, 81,<br />
85, 86, 91, 92, 93, 96, 97, 98, 99,<br />
100, 101, 103, 106, 107, 108, 110,<br />
111, 112, 113, 114, 115, 116, 117,<br />
118, 120, 121, 124, 128, 129, 130<br />
branch<strong>ed</strong>, 86, 122<br />
capitate, 96, 104<br />
double (bifurcate), 95, 98, 103, 113<br />
feathery (plumose), 35, 82, 87, 105,<br />
123<br />
style, 27, 29, 32, 33, 36, 37, 77, 81, 84,<br />
86, 88, 91, 95, 97, 98, 99, 100,<br />
101, 103, 108, 109, 111, 112, 113,<br />
114, 115, 117, 118, 119, 120, 121,<br />
124, 128, 129<br />
Pisum, 12, 40, 100<br />
Pitcher-plant, 23, 91<br />
Pitcher-plant Family, 91<br />
Planera albelica, 82<br />
Plantain, 38<br />
Plant body, 8, 9, 11<br />
Plant communities, 76<br />
Plant Kingdom (Plantae), 41,<br />
Bryophyta, 41, 63<br />
Anthocerotae (Hornworts), 63<br />
Hepaticae (Liverworts), 63<br />
Musci (Mosses), 63<br />
Charophyta (Stoneworts), 41, 62<br />
Chlorophyta (Green Algae), 41, 58<br />
Cycadophyta (Cycads), 41, 71<br />
Equisetophyta (Horsetails & Scouring<br />
Rushes), 41, 66<br />
Ginkgophyta, 41, 72<br />
Gnetophyta (Gnetes), 41, 74<br />
Lycopodiophyta, 41, 65<br />
Isoetales (Quillworts), 65<br />
Lycopodiales (Clubmosses), 65<br />
Selaginellales (Spikemosses), 65<br />
Magnoliophyta (Flowering Plants), 41,<br />
75<br />
Liliopsida (monocotyl<strong>ed</strong>ons), 75<br />
Magnoliopsida (dicotyl<strong>ed</strong>ons), 75<br />
Phaeophyta (Brown Algae), 41, 59, 60,<br />
61
Ectocarpales, 59<br />
Fucales, 61<br />
Laminariales (kelps), 60<br />
Pinophyta (Conifers), 41, 73<br />
Polypodiophyta (Ferns), 41, 67<br />
Marsileales (water ferns), 70<br />
Ophioglossales (adder’s-tongue<br />
ferns), 67<br />
Polypodiales (common ferns), 68, 69<br />
Salviniales (floating ferns), 70<br />
Psilophyta (Whisk Ferns), 41, 64<br />
Rhodophyta (R<strong>ed</strong> Algae), 41, 57<br />
Bangiophycidae, 57<br />
Florideophycidae, 57<br />
Plantago, 38<br />
Plasmolysis, 5<br />
Plasmopara viticola, 46<br />
Platycerium, 67<br />
Pleurotus, 50<br />
Plum, 99<br />
Poa, 123<br />
Poaceae (Grass Family), 10, 15, 19, 22,<br />
23, 24, 35, 38, 76, 122, 123, 125<br />
Podosphaera, 48<br />
Poinciana, 100<br />
Poinsettia, 23, 26, 103<br />
Poison-ivy, 106<br />
Poison-oak, 106<br />
Poison-sumac, 106<br />
Poison-wood, 106<br />
Pollen (pollen grain), 27, 30, 31, 33, 34,<br />
35, 36, 37, 71, 72, 73, 74, 75, 92,<br />
94, 97, 108, 111, 112, 113, 115,<br />
118, 119, 120, 124, 127, 129, 130<br />
Pollen sac, see Stamen structure<br />
Pollen tube, 31, 37<br />
Pollination, 33, 34, 35, 36, 37<br />
cross-pollination, 33, 92, 109, 113<br />
self-pollination, 33, 92, 109, 125<br />
wind pollination, 33, 35, 75, 82, 83, 84,<br />
88, 89, 95, 105, 123, 125<br />
Pollinators<br />
bats, 36<br />
birds, 36, 116<br />
insects, 33, 34, 35, 75, 81, 92, 95, 109,<br />
113, 125, 127, 129, 130<br />
bees, 34, 110, 113, 115, 129<br />
beetles, 33<br />
butterflies, 33<br />
flies, 34, 127<br />
moths, 33, 34, 117<br />
Polygamodioecious condition, 28, 102<br />
Polygamomonoecious condition, 28<br />
Polygonaceae, 89<br />
Polygonatum, 128<br />
Polygonum, 89<br />
Polyploidy, 6<br />
Polypodiophyta, 41, 67, 68, 69, 70<br />
Polyporus, 50<br />
Polysiphonia, 57<br />
Poncirus, 107<br />
Pond spice, 78<br />
Poplar, 35, 95<br />
Poppy, 38<br />
Poppy mallow, 90<br />
Populus, 95<br />
Porana paniculata, 112<br />
Porcupine s<strong>ed</strong>ge, 122<br />
Porphyra, 57<br />
Potato, 3, 16, 46, 111<br />
Pothos, 127<br />
Prayer plant, 124<br />
Precatory bean, 100<br />
Prickly ash, 107<br />
Prickly-pear, 85<br />
Privet, 114<br />
Protein (amino acids), 2, 3, 6, 24, 34, 36,<br />
37, 40, 43, 123<br />
Prunus, 39, 99<br />
Pseudotsuga, 73<br />
Psilocybe, 50<br />
Psilophyta, 41, 64<br />
Psilotum, 43, 64<br />
Ptelea, 107<br />
Pteridium, 67<br />
Pterocephalus, 118<br />
Puccinia, 49<br />
Pueraria lobata, 100<br />
Puffball, 53<br />
Pumpkin, 94<br />
Pyracantha, 99<br />
Pyrethrum, 119<br />
Pyrola, 97<br />
Pyrrophyta, 41, 55<br />
Pyrus, 99<br />
Pythium debaryanum, 46<br />
Pyxie cup, 54<br />
Quaking aspen, 95<br />
Quamoclit pennata, 112<br />
Queen Anne’s lace, 109<br />
Queen-<strong>of</strong>-the-border, 90<br />
Queen palm, 125<br />
Quercus, 38, 83<br />
Quillworts, 41, 42, 65<br />
Quince, 8, 99<br />
Radish, 96<br />
Raffia, 125<br />
Ragwe<strong>ed</strong>, 119<br />
Ragwort, 119<br />
Ramonda, 116<br />
Ranunculaceae, 80<br />
Ranunculus, 80<br />
Raphanus, 96<br />
Raphia, 125<br />
Rasamala, 81<br />
Raspberry, 99<br />
Rechsteineria, 116<br />
R<strong>ed</strong> Algae, 4, 41, 57<br />
R<strong>ed</strong> campion, 87<br />
R<strong>ed</strong> crown cactus, 85<br />
R<strong>ed</strong>-hot-poker, 128<br />
R<strong>ed</strong>leg, 89<br />
R<strong>ed</strong>-osier dogwood, 101<br />
R<strong>ed</strong> squill, 128<br />
R<strong>ed</strong>wood, 15, 73<br />
Reindeer moss, 54<br />
Reproduction<br />
asexual:<br />
budding, 47<br />
division (fission), 3, 7, 43, 44, 47, 55,<br />
56<br />
fragmentation, 47, 56, 57, 59, 63<br />
asexual structures:<br />
akinete, 44<br />
bulb, 8, 12, 16, 18, 128, 129<br />
conidium, 47, 48<br />
corm, 12, 16, 18, 65, 128, 129<br />
cyst, 55, 58<br />
gemma, 63, 64<br />
isidium, 54<br />
pseudobulb, 16, 130<br />
pycnidium, 54<br />
rhizome, 16, 20, 65, 66, 67, 68, 70,<br />
79, 92, 108, 124, 128, 129<br />
sporangium (spore case), 46, 59, 60,<br />
64, 65, 66, 67, 68<br />
sporocarp, 70<br />
stolon, 16, 20<br />
strobilus, 65, 66<br />
tuber, 3, 8, 16, 18, 112, 130<br />
tuberous root, 18<br />
sexual:<br />
anisogamy, 55, 59<br />
isogamy, 55, 59<br />
oogamy, 56, 57, 59, 60, 61, 62<br />
sexual structures:<br />
aethalium, 45<br />
antheridium, 46, 56, 60, 61, 62, 63,<br />
64, 66, 67<br />
archegonium, 63, 64, 66, 67<br />
ascus, 47, 48<br />
basidium, 49, 50, 51, 52, 53<br />
carpogonium, 57<br />
gametangium, 46, 59<br />
megasporangium, 32, 65<br />
microsporangium, 31, 65, 71<br />
oogonium, 46, 56, 60, 61, 62<br />
plasmodiocarp, 45<br />
sporangium (spore case), 45, 46, 47,<br />
49, 71, 72, 74<br />
strobilus, 71, 72, 73, 74<br />
trichoblast, 57<br />
Resin, 2, 10, 15, 22, 98, 106<br />
Respiration, 3, 24, 43<br />
Rex begonia, 93<br />
Rhapidophyllum, 125<br />
Rhapis, 125<br />
Rheum, 89<br />
Rhizine, 54<br />
Rhizobium radicicola, 43<br />
Rhizoid, 57, 58, 62, 63, 64<br />
Rhizome, 16, 20, 65, 66, 67, 68, 70, 79,<br />
92, 108, 124, 128, 129<br />
Rhizophora, 12<br />
Rhizophore, 65<br />
Rhizopus, 47<br />
Rhododendron, 38, 97<br />
Rhodophyta, 41, 57<br />
Rhoeo, 121<br />
Rhubarb, 89<br />
Rhubarb chard, 88<br />
Rhus, 106<br />
Rhynia, 43<br />
Ribes, 98<br />
Rice, 3, 19, 26, 38, 44, 70, 123<br />
Ricinus communis, 103<br />
Rinorea, 92<br />
River-bank grape, 104<br />
RNA (ribonucleic acid), 2, 3, 24<br />
Rock cress, 96<br />
Robinia, 38, 100<br />
Roccella, 54<br />
143
Rocket, 96<br />
Root, external structure, 12, 13, 17, 20,<br />
40<br />
coleorhiza, 40<br />
nodule, 12, 43, 100<br />
root cap, 3, 9, 13, 20<br />
root hair, 9, 10, 13, 17<br />
root tip (apex), 9, 13, 25, 40<br />
Root types, 12<br />
adventitious roots, 12, 13, 16, 123, 129<br />
aerial roots, 12, 20<br />
contractile roots, 12<br />
lateral root, 12, 13, 20<br />
primary root, 12<br />
prop roots, 12<br />
radicle, 12, 40<br />
seminal roots, 12<br />
storage roots, 12, 18<br />
tap root, 12, 109<br />
tuberous roots, 18<br />
Rosa, 99<br />
Rosaceae (Rose Family), 39, 99<br />
Rose, 99<br />
Rose cactus, 85<br />
Rose Family, 39, 99<br />
Rosemary, 113<br />
Rose-<strong>of</strong>-China, 29, 90<br />
Rose-<strong>of</strong>-Sharon, 26, 90<br />
Roselle, 90<br />
Rosidae, 75<br />
Rosmarinus, 113<br />
Royal fern, 67, 68<br />
Royal palm, 125<br />
Royal water lily, 79<br />
Roystonea regia, 125<br />
Rubus, 39, 99<br />
Rubutia, 85<br />
Rudbeckia hirta, 26, 119<br />
Rue anemone, 80<br />
Rumex crispus, 38<br />
Rumohra adiantiformis, 69<br />
Rush Family, 35<br />
Russelia, 115<br />
Russula, 51<br />
Rusty ho<strong>of</strong> fungus, 52<br />
Ruta, 107<br />
Rutabaga, 96<br />
Rutaceae (Rue Family), 39, 107<br />
Rye, 19, 48, 123<br />
Ryegrass, 26<br />
Sabal palmetto, 125, 126<br />
Sacaline, 89<br />
Saccharomyces, 47<br />
Saccharum, 123<br />
Saffron, 129<br />
Sage, 113<br />
Sagittaria latifolia, 120<br />
Sago palm, 125<br />
Saguaro cactus, 36<br />
Saint Augustine grass, 123<br />
Saintpaulia ionantha, 116<br />
Salicaceae (Willow Family), 35, 95<br />
Salix (willow), 10, 35, 95<br />
Salvia, 113<br />
Salvinia, 70<br />
Sambucus, 117<br />
Sandwort, 87<br />
144<br />
Sansevieria, 20, 128<br />
Sap, 2, 8, 18, 79, 89, 103, 110, 112, 127<br />
Saponaria, 87<br />
Saprolegnia, 46<br />
Saprophyte, 46, 49, 115, 130<br />
Sarracenia, 23, 91<br />
Sarraceniaceae, 91<br />
Sassafras albidum, 78<br />
Satureja, 113<br />
Saucer magnolia, 77<br />
Savory, 113<br />
Saw-palmetto, 125<br />
Saxifraga, 16, 98<br />
Saxifragaceae, 98<br />
Saxifrage Family, 98<br />
Scabiosa, 118<br />
Scarlet oak, 83<br />
Scarlet sage, 113<br />
Scen<strong>ed</strong>esmus, 58<br />
Scent (odor, aroma, fragrance), 33, 34,<br />
35, 36, 62, 72, 78, 98, 109, 111,<br />
113, 127, 130<br />
Schinopsis, 106<br />
Schizanthus, 111<br />
Scirpus, 122<br />
Schlumbergera, 26, 85<br />
Scilla, 128<br />
Scindapsis, 127<br />
Scotch elm, 82<br />
Scleranthus, 87<br />
Sclerotium, 45, 48<br />
Scouring rush, 20, 41, 42, 66<br />
Script lichen, 54<br />
Scrophularia, 115<br />
Scrophulariaceae, 115<br />
Sea grape, 89<br />
Sea holly, 109<br />
Secale cereale (rye), 19, 48, 123<br />
S<strong>ed</strong>ge, 122<br />
S<strong>ed</strong>ge Family, 23, 76, 122<br />
Se<strong>ed</strong>, 27, 37, 38, 39, 40, 41, 71, 72, 73,<br />
74, 77, 79, 81, 82, 84, 86, 87, 90,<br />
92, 93, 95, 96, 99, 100, 102, 105,<br />
106, 107, 108, 110, 111, 128, 129,<br />
130<br />
Se<strong>ed</strong> ferns, 41, 42<br />
Se<strong>ed</strong>ling, 20, 40<br />
Se<strong>ed</strong> structure, 37, 40<br />
aleurone, 40, 123<br />
coleoptile, 20, 40<br />
coleorhiza, 40<br />
coma (surface hairs), 10, 90, 95<br />
embryo, 12, 37, 40, 75, 107, 123<br />
endosperm, 8, 37, 40, 75, 123, 125,<br />
130<br />
epicotyl, 40<br />
hilum, 40<br />
plumule, 40<br />
radicle, 12, 40<br />
se<strong>ed</strong> coat (testa), 20, 37, 40, 123<br />
se<strong>ed</strong> leaf (cotyl<strong>ed</strong>on), 1, 8, 37, 40, 72,<br />
75<br />
scutellum, 40<br />
Se<strong>ed</strong> types<br />
angiosperm, 41, 75<br />
dicot, 40, 75<br />
monocot, 40, 75<br />
gymnosperm, 41, 71, 72, 74<br />
conifer, 40, 41, 71, 73<br />
cycad, 41, 71<br />
Ginkgo, 41, 71, 72<br />
gnete, 41, 71, 74<br />
Selaginella, 65<br />
Semibegoniella, 94<br />
Senecio, 119<br />
Senna, 100<br />
Sensitive fern, 67<br />
Sensitive plant, 100<br />
Sentinel palm, 125<br />
Sentry palm, 125<br />
Sequoiadendron giganteum, 73<br />
Sequoia sempervirens, 73<br />
Serenoa, 125<br />
Setaria, 123<br />
Shaggy mane, 51<br />
Shallot, 128<br />
Sheepberry, 117<br />
Shepherd’s purse, 96<br />
Shinleaf, 97<br />
Shoot, 9, 19, 20, 37, 40<br />
bud, 14, 19, 25, 29<br />
plumule, 40<br />
spur shoot, 16, 72, 99<br />
tiller, 19<br />
tip (apex), 14, 15, 16, 18<br />
Siberian elm, 82<br />
Sidalcea, 90<br />
Silica, 2, 10, 56, 66<br />
Silver-lace vine, 89<br />
Silver maple, 14, 38, 105<br />
Silver palm, 125<br />
Silvery lupine, 100<br />
Sinningia, 116<br />
Sisyrinchium, 129<br />
Skunk cabbage, 34, 127<br />
Slime molds, 41, 45<br />
Slipper-flower, 115<br />
Smartwe<strong>ed</strong>, 89<br />
Smilacina, 128<br />
Smilax, 16, 128<br />
Smithiantha, 116<br />
Smoke tree, 106<br />
Snake plant, 128<br />
Snapdragon, 115<br />
Sneezewe<strong>ed</strong>, 119<br />
Snowberry, 117<br />
Solanaceae, 111<br />
Solanum<br />
dulcamara, 111<br />
nigrum, 111<br />
pseudocapsicum, 111<br />
tuberosum (potato), 3, 16, 111<br />
Solidago, 38, 119<br />
Solomon’s seal, 128<br />
Sonchus, 119<br />
Sorbus, 99<br />
Sorghum bicolor, 24, 123<br />
Sorus, 67, 68<br />
South African stinkwood, 78<br />
Sow-thistle, 119<br />
Soybean, 100<br />
Spadix, 34, 75, 127<br />
Spathe, 34, 75, 127<br />
Spathiphyllum, 127<br />
Spatterdock, 79<br />
Spiraea, 99
Spe<strong>ed</strong>well, 115<br />
Sperm, 31, 37, 56, 59, 60, 61, 62, 63, 64,<br />
66, 67, 71<br />
Sphaerotheca, 48<br />
Sphagnum, 63<br />
Spice bush, 78<br />
Spiderwort, 121<br />
Spiderwort Family, 121<br />
Spikemosses, 41, 42, 65<br />
Spinach, 26, 88<br />
Spinacia oleracea, 26, 88<br />
Spinulose woodfern, 68<br />
Spirillum lip<strong>of</strong>erum, 43<br />
Spirogyra, 58<br />
Spore, 45, 46, 47, 48, 49, 50, 53, 54, 57,<br />
63, 65, 66, 67<br />
ascospore, 47, 48, 54<br />
basidiospore, 49, 50, 51, 53, 54<br />
carpospore, 57<br />
conidium, 47, 48<br />
endospore, 43<br />
exospore, 44<br />
megaspore, 27, 32, 65, 70<br />
microspore, 31, 65, 70, 71<br />
oospore, 46, 56, 62<br />
statospore, 56<br />
teleutospore, 49<br />
tetraspore, 57<br />
zoospore, 46, 56, 59, 60<br />
zygospore, 47<br />
Sporophyte, 40, 59, 60, 63, 64, 66, 67<br />
Spruce, 73, 76<br />
Spurge Family, 16, 103<br />
Squash, 94<br />
Squill, 128<br />
Staff-tree Family, 102<br />
Stagger-bush, 97<br />
Stagger-grass, 128<br />
Staghorn fern, 67<br />
Staghorn sumac, 106<br />
Stamen structure, 27, 28, 30, 31, 33, 35,<br />
36, 75, 77–130<br />
androecial types:<br />
didynamous, 115<br />
monadelphous, 90<br />
tetradynamous, 96<br />
anther (pollen sac), 27, 29, 30, 31, 33,<br />
35, 77, 78, 79, 81, 82, 90, 93, 94,<br />
97, 106, 108, 110, 111, 112, 113,<br />
114, 116, 119, 120, 121, 123, 124,<br />
127, 128, 129<br />
connective, 27, 93, 113<br />
filament, 27, 29, 31, 35, 36, 79, 87, 90,<br />
94, 96, 97, 100, 104, 106, 107,<br />
108, 111, 112, 113, 119, 120, 121,<br />
127, 128, 129<br />
pollen, see Pollen<br />
staminode, 78, 116, 121, 124<br />
tapetum, 31<br />
Stanhopea, 130<br />
Stapelia, 110<br />
Star anise, 77<br />
Starch, 3, 13, 24, 36, 37, 39, 40, 55, 57<br />
Star magnolia, 77<br />
Star-<strong>of</strong>-Bethlehem, 128<br />
Starwort, 87<br />
Stellaria, 87<br />
Stem, external structure, 14, 15, 40<br />
areole, 85, 86<br />
bud scale scar, 14<br />
internode, 14, 15, 16, 25, 62, 66<br />
leaf scar, 14, 35, 71, 83<br />
lenticel, 14, 15, 17<br />
node, 14, 16, 21, 62, 66, 74, 85, 87,<br />
89, 100, 104<br />
spur shoot, 16, 77, 99<br />
vascular bundle scar, 14<br />
Stemonitis, 45<br />
Stem types<br />
bulb, 8, 13, 16, 18, 128, 129<br />
conifer, 9, 15<br />
corm, 12, 16, 18, 65, 128, 129<br />
dicot, 9, 15<br />
herbaceous stem, 1, 9, 15, 65<br />
monocot, 9, 15<br />
p<strong>ed</strong>icel, 27, 35, 39, 78, 95, 96, 100,<br />
102, 103, 104, 106, 107, 108, 109,<br />
110, 111, 113, 114, 115, 116, 120,<br />
121<br />
p<strong>ed</strong>uncle, 26, 27, 29, 33, 34, 36, 39,<br />
79, 80, 81, 91, 92, 98, 99, 101,<br />
103, 107, 108, 109, 110, 112, 115,<br />
117, 119, 120, 121, 124, 127, 128,<br />
129, 130<br />
pseudobulb, 16, 130<br />
rhizome, 16, 20, 65, 66, 67, 68, 70, 79,<br />
92, 108, 124, 128, 129<br />
stolon, 16, 20<br />
storage stem, 16<br />
succulent (fleshy) stem, 16, 17, 85, 93,<br />
103<br />
tuber, 3, 8, 16, 18, 112, 128, 130<br />
vine, 12, 16, 20, 67, 74, 78, 80, 89, 94,<br />
97, 102, 104, 106, 111, 113, 114,<br />
116, 117, 119<br />
woody stem, 1, 9, 15, 72, 73<br />
Stenotaphrum, 123<br />
Stephanotis floribunda, 110<br />
Stinkhorns, 53<br />
Stock, 96<br />
Stomata, 10, 15, 17, 22, 23<br />
Stoneworts, 41, 62<br />
Stork’s-bill, 108<br />
Strawberry, 20, 26, 39, 99<br />
Strawberry-blite, 88<br />
Strawberry begonia, 16, 98<br />
Strawflower, 119<br />
Strelitziaceae, 124<br />
Streptocarpus, 116<br />
String-<strong>of</strong>-hearts, 110<br />
Strip<strong>ed</strong> inch plant, 121<br />
Strobilus, 65, 66, 71, 72, 73, 74<br />
Stroma, 3, 24, 48<br />
Stylites, 65<br />
Succulent plants, 17, 23, 67, 76, 93, 103,<br />
110, 128<br />
Sugar, 2, 5, 10, 18, 24, 33, 37<br />
Sugar beet, 88<br />
Sugar cane, 24, 123<br />
Sugar maple, 26, 105<br />
Sugar palm, 125<br />
Suillus, 51<br />
Sulfur mushroom, 50<br />
Sumac, 106<br />
Sundew, 23<br />
Sunflower, 19, 119<br />
Swamp laurel, 97<br />
Swamp mallow, 90<br />
Sweet alyssum, 96<br />
Sweet-bay, 77<br />
Sweet bay, 78<br />
Sweet cicely, 109<br />
Sweet clover, 100<br />
Sweet gum, 81<br />
Sweet orange, 107<br />
Sweet pea, 100<br />
Sweet potato, 12, 112<br />
Swiss chard, 88<br />
Swiss-cheese plant, 127<br />
Sycamore maple, 105<br />
Symbegonia, 93<br />
Symphoricarpos, 117<br />
Symplocarpus foetidus, 34, 127<br />
Synchytrium, 46<br />
Synechococcus, 44<br />
Syringa vulgaris, 14, 114<br />
Tagetes patula, 75, 119<br />
Tahitian bridal veil, 121<br />
Talauma, 77<br />
Tamarack, 73<br />
Tamarind, 100<br />
Tamarindus, 100<br />
Tangerine, 107<br />
Tannia, 127<br />
Tannin, 10, 15, 22<br />
Tan oak, 83<br />
Taphrina, 47<br />
Tapioca, 103<br />
Taraxacum, 119<br />
Taro, 127<br />
Tarragon, 119<br />
Taxodium, 73<br />
Taxus, 73<br />
Teasel, 118<br />
Teasel Family, 118<br />
Temple bells, 116<br />
Tendril, 16, 94, 100, 104<br />
Tetradymia, 119<br />
Tetragonia expansa, 88<br />
Tetraphis, 63<br />
Thanksgiving cactus, 26, 85<br />
Thalia dealbata, 124<br />
Thalictrum, 80<br />
Thistle, 119<br />
Thlaspi, 96<br />
Thrinax, 125<br />
Thuja, 73<br />
Thyme, 113<br />
Thymus, 113<br />
Tilletia, 49<br />
Timothy, 123<br />
Tissue<br />
dermal tissue, 9, 13<br />
collenchyma, 15, 39<br />
cortex, 8, 9, 13, 15, 17, 72<br />
endodermis, 9, 13, 17, 22<br />
endosperm, 8, 37, 40, 75, 123, 125,<br />
130<br />
epidermis, 8, 9, 10, 13, 15, 22, 23, 24,<br />
39<br />
ground tissue, 9, 13, 15, 22<br />
hypodermis, 22<br />
leaf tissue, 17, 22<br />
145
mesophyll, 15, 17, 22, 23, 24<br />
parenchyma, 8, 13, 15, 16, 18, 22, 38,<br />
39, 56<br />
pericycle, 9, 13, 17<br />
periderm (outer bark), 9, 15, 102<br />
phelloderm, 9, 15<br />
pith, 8, 9, 15, 72, 122<br />
root tissue, 13<br />
sclerenchyma, 8, 13, 15, 22, 38<br />
stem tissue, 15<br />
transfusion tissue, 22<br />
vascular tissue, 2, 8, 9, 11, 13, 15, 17,<br />
18, 22, 37, 42, 63<br />
phloem (food-conducting), 8, 9, 11,<br />
13, 15, 17, 18, 22, 24, 42<br />
xylem (water-conducting), 2, 8, 9,<br />
11, 13, 15, 17, 18, 22, 24, 42<br />
Tmesipteris, 43, 64<br />
Tobacco, 34, 111<br />
Tomato, 3, 4, 111<br />
Tooth<strong>ed</strong> fungus, 52<br />
Torch lily, 128<br />
Torenia, 115<br />
Toxicodendron, 106<br />
Trachycarpus fortunei, 125<br />
Trachymeme, 109<br />
Tradescantia, 121<br />
Translocation, 18<br />
Transpiration, 10, 17<br />
Trebouxia, 54<br />
Tree fern, 67<br />
Tree-mallow, 90<br />
Tremella, 49<br />
Trifoliate orange, 107<br />
Trifolium, 12, 26, 33, 100<br />
Trillium, 128<br />
Tripterygium, 102<br />
Triticum (wheat), 19, 49, 123<br />
aestivum, 26<br />
Tropisms, 20<br />
Truffle, 48<br />
Tsuga, 73<br />
Tuber, 3, 8, 16, 18, 112, 128, 130<br />
Tuber, 48<br />
Tuberous begonia, 12, 93<br />
Tulip, 128<br />
Tulipa, 128<br />
Tulip tree, 77<br />
Turgor pressure, 5, 10, 123<br />
Turkey tail fungus, 52<br />
Twinflower, 117<br />
Typhaceae (Cattail Family), 35<br />
Ulmaceae (Elm Family), 35, 82<br />
Ulmus, 38, 82<br />
Umbellularia californica, 78<br />
Umbrella plant, 122<br />
Umbrella s<strong>ed</strong>ge, 122<br />
Umbrella tree, 77<br />
Urginea, 128<br />
146<br />
Urocystis cepulae, 49<br />
Urophlyctis, 46<br />
Usneas, 54<br />
Ustilago, 49<br />
Utricularia, 23<br />
Uvularia, 128<br />
Vaccinium, 97<br />
Vanda, 130<br />
Vanilla, 130<br />
Varnish tree, 106<br />
Vascular bundle (vein), 8, 9, 11, 14, 15,<br />
22, 23, 24, 25, 99<br />
Vaucheria, 56<br />
Velvet-leaf, 90<br />
Vein, see Vascular bundle<br />
Venus’-flytrap, 23<br />
Veratrum, 128<br />
Verbascum thapsus, 115<br />
Vernal witch hazel, 81<br />
Veronica, 115<br />
Verpa,48<br />
Vetch, 100<br />
Viburnum, 117<br />
Vicia, 100<br />
Victoria amazonica, 79<br />
Viola, 23, 92<br />
Violaceae, 92<br />
Violet, 23, 92<br />
Violet Family, 92<br />
Virginia creeper, 16, 104<br />
Vitaceae, 104<br />
Vitamin, 24, 92, 123<br />
Vitis (grape), 16, 39, 104<br />
Vivipary, 107<br />
Voodoo lily, 127<br />
Wafer ash, 107<br />
Walking fern, 67<br />
Walnut bean, 78<br />
Wandering Jew, 121<br />
Wapato, 120<br />
Washingtonia filifera, 125<br />
Water canna, 124<br />
Water clover, 70<br />
Water cress, 96<br />
Water fern, 44, 70<br />
Water hemlock, 109<br />
Water lettuce, 127<br />
Water lily, 79<br />
Water Lily Family, 79<br />
Watermelon, 94<br />
Water-plantain, 120<br />
Water-plantain Family, 120<br />
Water shield, 79<br />
Water spangles, 70<br />
Wattle, 100<br />
Wax begonia, 93<br />
Wax-plant, 110<br />
Wayfaring tree, 117<br />
Weigela, 117<br />
Welwitschia, 15, 74<br />
West Indian arrowroot, 124<br />
West Indian silkwood, 107<br />
Wheat, 19, 26, 49, 123<br />
Whisk ferns, 41, 64<br />
White birch, 84<br />
White campion, 87<br />
White snakeroot, 119<br />
Wild black currant, 98<br />
Wild buckwheat, 89<br />
Wild cabbage, 96<br />
Wild calla, 127<br />
Wild carrot, 38, 109<br />
Wild mustard, 96<br />
Williamsonia, 42<br />
Willow, 10, 35, 95<br />
Willow Family, 35, 95<br />
Wind flower, 80<br />
Wing<strong>ed</strong> wahoo, 102<br />
Wintergreen, 97<br />
Winter hazel, 81<br />
Wishbone flower, 115<br />
Wisteria, 100<br />
Witch hazel, 81<br />
Witch Hazel Family, 81<br />
Wolffia, 75<br />
Wood, 1, 9, 14, 15, 72, 73, 75<br />
Wood rose, 16, 112<br />
Xanthium strumarium, 26, 119<br />
Xanthoria, 54<br />
Xanthosoma, 127<br />
Xylaria, 48<br />
Xylem, 2, 8, 9, 11, 13, 15, 17, 18, 22, 24,<br />
42<br />
Yeast, 47<br />
Yellow-green Algae, 41, 56<br />
Yellow poplar, 77<br />
Yellow water lily, 79<br />
Yew, 73<br />
Yucca, 15<br />
Yulan magnolia, 77<br />
Zamia furfurscea, 71<br />
Zant<strong>ed</strong>eschia, 127<br />
Zanthoxylum, 107<br />
Zea mays (corn), 12, 19, 24, 40, 123<br />
Zebrina pendula, 121<br />
Zingiberaceae, 124<br />
Zingiberales, 124<br />
Zingiberidae, 75<br />
Zinnia, 119<br />
Zoysia, 123<br />
Zoysia grass, 123<br />
Zygadenus, 128<br />
Zygomycota, 41, 47<br />
Zygote, 37, 45, 46, 60, 62, 63, 64, 66,<br />
67