Mycol. Res. 101 (12) : 1531–1534 (1997)
1531
Printed in the United Kingdom
Two new coelomycetes with appendaged conidia on stems of
eucalypts from Australia
Z I Q I N G Y U A N1, 2 A N D C A R O L I N E M O H A M M E D1, 2
" Department of Agricultural Science, University of Tasmania, GPO Box 252-54, Hobart, Tas. 7001, Australia
# CSIRO, Forestry and Forest Products, Tasmanian Research Centre, GPO Box 252-12, Hobart, Tas. 7001, Australia
Two new coelomycetes with appendaged conidia collected on branches of Eucalyptus species in Tasmania are described, illustrated
and compared with closely related taxa. They are Ciliosporella tuberculiformis sp. nov. on E. regnans and Neoplaconema cymbiforme
sp. nov. on E. nitens.
Fourteen mitosporic fungal species associated with eucalypt
stem cankers or dead branches in Tasmania are reported in
Yuan & Mohammed (1997 a). Seven of these species are
undescribed with the exception of Seiridium papillatum Z. Q.
Yuan (Yuan & Mohammed, 1997 b). This paper describes
another of the unnamed species and one recently collected
coelomycetous fungus, Ciliosporella tuberculiformis and
Neoplaconema cymbiforme.
Ciliosporella tuberculiformis was collected on Eucalyptus
regnans F. Muell. on two occasions at a single locality. Fruit
bodies are typically immersed in wart-like swellings on either
healthy or dead tissue at the edge of necrotic lesions
associated with stem tip dieback (Fig. 4). Neoplaconema
cymbiforme was associated with cankers at branch bases of
trees in plantations of E. nitens (Deane & Maiden) Maiden with
severe Mycosphaerella leaf disease. Both fungi have sufficiently
distinctive characteristics to be proposed as new anamorphspecies. This is the first time members of Ciliosporella Petr. and
Neoplaconema B. Sutton have been found on eucalypts in the
southern hemisphere.
Microscopic examination of each specimen was carried out
on squash mounts and thin median sections. The material was
mounted in Shear’s mounting fluid or lactophenol. Fifty
mature conidia were measured for each species, and arithmetic
means calculated.
The holotypes are deposited in the Herbarium of the
Institute for Horticultural Development, Knoxfield, Australia
(VPRI).
DESCRIPTION AND DISCUSSION
Ciliosporella tuberculiformis Z. Q. Yuan & C. Mohammed,
sp. nov.
(Figs 1–7)
Etym. : refers to the association of the fungal fruiting bodies
with wart-like swellings of host tissue.
Conidiomata caulicola, pycnidialia, immersa, discreta vel gregaria
catervatim, globosa vel subglobosa, 125–195 µm lata, 100–175 µm
alta, dehiscentia e fissura apicali ; paries 15–20 µm crassus, ad apicem
25–30 µm crassus, e textura angulari parietibus crassis brunnea vel
pallide brunneisque compositus. Conidiophora 15 µm longa, stratum
intimum telae basalis conidiomatum tegentia, hyalina, ramosa et 1–3-
Figs 1–3. Ciliosporella tuberculiformis. Fig. 1. Conidia. Fig. 2.
Conidiophores. Fig. 3. Vertical section of conidioma (bar, 20 µm for
Figs 1, 2 ; 50 µm for Fig. 3).
New coelomycetes on eucalypts
1532
Figs 4–7. Ciliosporella tuberculiformis. Fig. 4. Conidiomata associated with wart-like swellings in necrotic lesions caused by stem tip
dieback. Fig. 5. Conidia. Fig. 6. Conidiophores. Fig. 7. Vertical section of conidioma (bar, 2 mm for Fig. 4 ; 25 µm for Figs 5, 6 ; 40 µm
for Fig. 7).
septata, glabro-tunicata, in muco involuta. Cellulae conidiogenae
5–7±5¬2±5–3 µm, discretae, ampulliformes vel lageniformes,
hyalinae, laeves. Conidia 30–45¬3±8–5 µm, unicellularia, hyalina,
fusiformia vel naviculata, vulge curvata, basi truncata et apice acuta,
laevia, guttulata et granulata ; appendix apicalis cellularis, singularis,
attenuata, rostrata vel tubularis, simplex, unicellularis, a corpore
conidii non secta, 4±5–7±5 µm longa ; ratione conidii long.}lat.
¯ 7±9 : 1.
In ramulis Eucalypti regnantis F. Muell., Florentine Valley, Westfield,
Tasmania, Australia, 15 Feb. 1996, Z. Q. Yuan 93 (VPRI 20828),
holotypus.
Caulicolous. Conidiomata pycnidial, immersed, scattered or
gregarious in groups on the upper surface of wart-like
swellings of branch tissue, globose to subglobose, small,
125–195 µm wide, 100–175 µm high, dehiscence by a split in
the apical wall ; wall 15–20 µm thick, up to 25–30 µm thick at
top parts, composed of textura angularis, cells thick-walled,
brown, becoming paler and thin-walled toward the conidial
hymenium. Conidiophores lining the cavity of the conidioma,
hyaline, 1–3-septate, branched, smooth, up to 15 µm long,
invested in mucus. Conidiogenious cells discrete, ampulliform to
lageniform, hyaline, 5–7±5¬2±5–3 µm. Conidia 30–45¬3±8–5
(mean 38¬4±8) µm, one-celled, hyaline, fusiform to naviculate,
mostly curved, with a truncate base and an acute apex,
smooth, guttulate and granular ; apex attenuated into a
rostrate, tubular, unbranched, cellular appendate (type A, sensu
Nag Raj, 1993), not separated from the conidium by a septum,
4±5–7±5 (mean 5) µm long ; mean conidium length}width ratio
¯ 7±9 : 1.
On moribund branches of Eucalyptus regnans.
Specimens examined : Tasmania, Florentine Valley, Westfield, on E.
regnans, 15 Feb. 1996, Z. Q. Yuan 93 (VPRI 20828), holotype ; same
locality and host, 22 Sep. 1996, Z. Q. Yuan 296.
Ciliosporella was proposed by Petrak (Annales mycologici 25 :
217, 1927), based on the type mitosporic species C. selenospora
Petr. So far the genus has remained monotypic (Hawksworth
et al., 1995). C. selenospora was described on stems of Trifolium
alpestre in Austria and is characterized by fusiform to naviculate,
one-celled, hyaline conidia bearing an apical rostrate, tubular,
unbranched appendage of type A (sensu Nag Raj, 1993).
The fungus collected on eucalypts in Tasmania fits the
concept for Ciliosporella given by Nag Raj (1993), even
though it is very different from C. selenospora in its host and
geographical distribution.
Ciliosporella tuberculiformis differs from C. selenospora in that
its conidiomata are always associated with wart-like swellings
on dying branches of eucalypt and the conidiomatal wall is
characteristically thicker at its apex. Conidia in C.
tuberculiformis are curved, filled with guttules and granules,
whilst those of C. selenospora are straight, without contents,
and much smaller (20–29¬2–3 µm for C. selenospora, fide Nag
Raj, 1993).
Z. Q. Yuan and Caroline Mohammed
1533
Figs 8–10. Neoplaconema cymbiforme. Fig. 8. Conidia. Fig. 9.
Conidiophores. Fig. 10. Vertical section of conidioma (bar, 20 µm for
Figs 8, 9 ; 150 µm for Fig. 10).
Conidial morphology in C. tuberculiformis is also similar to
that of Monochaetiella hyparrheniae E. Castell. which has
fusiform to naviculate, unicellular conidia bearing an apical
appendate of type A (Nag Raj, 1993). M. hyparrheniae,
however, has conidiomata of typical acervuli and much wider
conidia with a mean conidium length}width ratio of 5±7 : 1.
Neoplaconema cymbiforme Z. Q. Yuan & C.
Mohammed, sp. nov.
(Figs 8–13)
Etym. : refers to the naviculate shape of the conidia.
Conidiomata caulicola, pseudostromatica, immersa, unilocularia,
400–500 µm diam., paries 12±5–20 µm crassus, e textura angulari
5–8 µm diam. parietibus tenuibusque compositus ; loculus
150–200 µm diam., e pseudoparenchymate texturae intricatae cum
hospiti cingulatus. Conidiophora hyalina, 1–2-septata, basi ramosa,
glabro-tunicata, in muco involuta. Cellulae conidiogenae
5–12±5¬2±5–4±0 µm, discretae vel integratae, lageniformes vel
cylindricae, laeves ; canalis minuta, cum parieti a latere incrassato.
Conidia 15±0–21±3¬2±5–4±0 µm, unicellularia, hyalina, tenui- vel
crassitunicata, naviculata, ad extrema attenuata, apice obtusa et basi
anguste truncata, recta vel raro leviter curvata, appendicem apicalem
ferentia ; appendix apicalis cellularis, singularis, attenuata, tubularis,
simplex, unicellularis, a corpore conidii secta, 7±5–11±3 µm longa ;
ratione conidii long.}lat. ¯ 5±45 : 1.
In ramulis Eucalypti nitentis, Basil’s Rd, Ridgley, North Forest
Products, Tasmania, Australia, 12 Sep. 1996, D. de Little 297 (VPRI
21090), holotypus.
Caulicolous. Conidiomata pseudostromatic, immersed, unilocular, black, ostiolate, 400–500 µm diam. ; wall composed of
thin-walled textura angularis (5–8 µm diam.) ; loculi
Figs 11–13. Neoplaconema cymbiforme. Figs 11, 12. Conidia. Fig.
13. Vertical section of conidioma (bar, 15 µm for Figs 11, 12 ; 90 µm
for Fig. 13).
150–200 µm diam., surrounded by pseudoparenchyma of
textura intricata intermixed with host tissue. Conidiophores
hyaline, 1–2-septate, branched at the base, smooth-walled,
invested in mucus. Conidiogenous cells hyaline, discrete or
integrated, lageniform to cylindrical, channel minute but
periclinal wall considerably thickened, smooth-walled,
5–12±5¬2±5–4±0 µm. Conidia 15±0–21±3¬2±5–4±0 (mean
16±9¬3±1) µm, unicellular, colourless, thin and smooth-walled,
naviculate, tapering towards both ends, with an obtuse apex
and a narrow truncate base, straight or occasionally slightly
curved, bearing an apical appendage of type A ; appendage
arising as a tubular extension of the conidium body and
delimited from it by a septum, unbranched, slightly attenuated,
flexuous, 7±5–11±3 (mean 9±6) µm long ; mean conidium
length}width ratio ¯ 5±45 : 1.
On cankered branch of Eucalyptus nitens.
Specimens examined : Tasmania, Basil’s Rd, Ridgley, North Forest
Products, on E. nitens (Deane & Maiden) Maiden, 12 Sep. 1996, D.
de Little (VPRI 21090), holotype.
Only a single species, N. napelli (Maire & Sacc.) B. Sutton,
is accepted in Neoplaconema (Sutton, 1977 ; Nag Raj, 1993), on
stems and branches of Aconitum napellum and A. toxicum from
Germany and Romania (Nag Raj, 1993). The conidia of N.
napelli are shorter but wider than those of N. cymbiforme, with
New coelomycetes on eucalypts
a mean conidium length}width ratio of 3±54 : 1 and apical
appendages up to 27 µm long ( fide Nag Raj, 1993).
Conidial shape, size and apical appendage in N. cymbiforme
are similar to those of Mastigosporella hyalina (Ellis & Everh.)
Ho$ hn. on leaves of Quercus coccinea (Nag Raj, 1993). Species
of Mastigosporella Ho$ hn., however, have pycnidial conidiomata
(without surrounding pseudostromatic tissue) and percurrently
proliferating conidiogenous cells. Conidia of Mastigosporella
do have apical appendages of type A as in Neoplaconema, but
they are not separated from the conidium by a septum.
The teleomorph of Neoplaconema has never been reported.
Some immersed, spherical perithecia were found adjacent to or
below the conidiomata of N. cymbiforme in the cankered area
of stems of the present collection, but no ascospores were
present.
The senior author wishes to thank the University of Tasmania
and CSIRO Forestry and Forest Products for his scholarship,
(Accepted 17 April 1997)
1534
and North Forest Products for partial financial assistance. Dr
D. de Little (North Forest Products, Tasmania) sent us one of
the specimens examined in the paper and for this we are
grateful.
REFERENCES
Hawksworth, D. L., Kirk, P. M., Sutton, B. C. & Pegler, D. N. (1995).
Ainsworth and Bisby’s Dictionary of the Fungi, 8th ed. CAB International :
Wallingford.
Nag Raj, T. R. (1993). Coelomycetous Anamorphs with Appendage-bearing
Conidia. Mycologue Publications : Waterloo, Canada.
Sutton, B. C. (1977). Nomenclature and taxonomy of Shanoria, Placonema and
Neoplaconema (Sphaeropsidales). Kew Bulletin 31, 461–464.
Yuan, Z. Q. & Mohammed, C. (1997 a). Investigation of fungi associated with
stem cankers of eucalypts in Tasmania, Australia. Australasian Plant
Pathology 26, (In press).
Yuan, Z. Q. & Mohammed, C. (1997 b). Seiridium papillatum, a new species
(mitosporic fungus) described on stems of eucalypts in Australia. Australian
Systematic Botany 10, 69–75.