Trans. Br. mycol. Soc. 90 (4), 619-625 (1988)

[ 619 ]

Printed in Great Britain

A NEW SPECIES OF WIESNERIOMYCES (HYPHOMYCETES)FROM SUBMERGED DECAYING LEAVES

By A. J. KUTHUBUTHEEN AND A. NAWAWI

Department of Botany, University of Malaya, 59100 Kuala Lumpur, Malaysia

Wiesneriomyces conjunctosporus sp. nov. with unicellular spores connected by narrow isthmiinto unbranched chains produced from a setose sporodochium is described and comparedwith the only other species in the genus, W. laurinus.

The genus Wiesneriomyces was erected by Koorders(1907) with W. javanicus as the type species. Kirk(1984) examined the holotype of Volutellarialaurina Tassi and showed that this provided anearlier name for Wiesneriomyces javanicus andhence proposed the new combination Wies-neriomyces laurinus (Tassi) P. M. Kirk. Volutellarialaurina, Chaetopeltis laurina (Tassi) Sacc., Tassialaurina (Tassi) H. & P. Sydow and Wiesneriomycesjavanicus Koorders were all reduced by Kirk(1984) to synonymy with W. laurinus. The fungusis evidently widespread and has been reportedfrom many parts of the world including Java(Koorders, 1907), India (Subramanian, 1956),Panama (Manotis & Strain, 1968), Papua-NewGuinea (Matsushima, 1971), Japan (Matsushima,1975), Taiwan (Matsushima, 1980), the BritishIsles (Kirk, 1983) and Australia (Shaw & Sutton,1985). It is also very common on a variety of leaf-litter in Malaysia. Wiesneriomyces laurinus is theonly species hitherto described in the genus.Matsushima (1975) described a Wiesneriomyces sp.(MFC 4038) which differs from W. laurinus inhaving shorter, 1-3 times branched conidiophoresand somewhat broader conidiogenous cells andconidia. The conidial lengths of the two, however,are similar.

In a survey of hyphomycetes on decayingsubmerged leaves in Malaysia, another species ofWiesneriomyces with conidia and conidiophoresmarkedly different from W. laurinus was isolated.

Wiesneriomyces conjunctosporus sp.nov.(Figs 1-11, 16-22)

Etym.: conjunctus (L.) - connected et spora-spore

Coloniae effusae, olivaceae ad atrobrunneae. Myceliumpartim superficiale, partim in substrato immersum, exhyphis ramosis, septatis, tuberculatis, pallide brunneis adbrunneis, 3'5-6 pm latiscompositum.Conidiomatasporo-dochia, solitaria vel 2-3 gregaria, pulvinata; stipitis

sporodochium teretiuscula, ex hyphis atra, turgida,crassitunicata, 2-3 pm diam composita; 2-10 setas basimferentia. Setae subulatae, apice acutae, septatae, atro-brunneae, crassitunicatae, laeves, ex strato conidio-phororum protrudentes, usque ad 650 pm altae, ad basim9-18 pm latae. Conidiophora semi-macronematosa, arctecontigua, ad basim pallide brunnea ad subhyalina, adapicem hyalina, septata, i -j-plo ramosa irregularia,37-60 flm alta, 1'5-3'0 pm lata. Cellulae conidiogenaeterrninales, clavatae, hyalinae, in conidiophoris incor-poratae. Conidia acrogenosa, hyalina, o-septata, albidaad brunneoalbida in massa (15-) 17-19 (-21) - cellularia,per isthmos breves connecta, cylindrica utrinqueattenuata, (280--) 330--340 (-360) I'll longa, U-, S- vel y-forrnata semper in tres dimensiones; cellula apicalisconicavelobclavata,hyalina, 12-13 flm longa, 2'7-3'5 flmlata; cellula basalis cylindrica vel bacillaria, subhyalina,15"5-18 pm longa, 3'6-4'2 pm lata; cellulae intermediaecylindricae, (14-) i8-20 (-25) pm longae, (3"6-) 4'5-5'0(-6) pm latae.

In foliis emortuis submersis angiospermae, PasuhForest Reserve, Negeri Sembilan, Malaysia, October1986, A. J. Kuthubutheen, IMI 318659, holotypus.

Colonies effuse, olivaceous-brown to darkbrown. Mycelium partly superficial, partly im-mersed in substratum, composed of branched,septate, tuberculate hyphae, 3'5-6,um wide, palebrown to brown. Conidiomata sporodochial,solitary to aggregates of 2-3, pulvinate, elevated bya dark pseudoparenchymatous stalk consisting ofdark inflated, thick-walled cells 2-3 ,urndiam, with2-10 setae arising from the margins of thepseudoparenchymatous base. Setae subulate, withacute apex, septate, thick-walled, dark brown,protruding above the level of conidiophores andconidial mass, up to 650,um tall, 9-18 ,urn wide atthe base. Conidiophores semi-macronematous,arising close to one another, pale brown tosubhyaline towards base, hyaline towards apex,septate, 1-3 times irregularly branched, withprimary, secondary and tertiary branches, 37-60,urn tall, 1'5-3'0,um wide, apex somewhat truncateto rounded, invariably with a single scar markingposition of conidial attachment. Conidiogenous cells

620 Wiesneriomyces conjunctosporus sp, nov.

A '---'100 pm B '-----'

lOpm c 50 urn

Fig, 1. Wiesneriomyces conjunctosporus, (A) Sporodochium; (B) conidiophores; (C) seta; (D) conidia,

terminal, clavate to cylindrical, hyaline, smooth,integrated, Conidia in whitish mass sometimesbecoming pale whitish brown, aerogenous, inuniseriate chains of (15-) 17-19 (-21) cells con-nected by narrow isthmi; conidial chains (280-)

330-340 (-360) /Lm long, hyaline, U-, S- or v:shaped, often in three planes; apical cell conical toobclavate, 12-13/Lm long, 2'7-3'5 /Lm wide; basalcell subhyaline, cylindrical to rod-shaped, 15"5-18/Lm long, 3'6-4'2 /Lm wide; intermediate cells along

A. J. Kuthubutheen and A. Nawawi 621

10

20 /tffi

11

\

20 /tffi

-I

Figs 2-11. Wiesneriomyces conjunctosporus. Figs 2-5. Sporodochia on the natural substratum. Fig. 6.Sporodochium showing coiled spore mass. Fig. 7. Sporodochium and conidiophores. Figs 8, 9.Conidiophores. Figs 10, 11. Conidia with basal cell arrowed.

622

12

Wiesneriomyces conjunctosporus sp. nov.

13

14 15

Figs 12-15. Wiesneriomyces laurinus. Figs 12-14. Sporodochia with incurved setae and conidia. Fig. 15.

Sporodochium with conidiophores.

A. J. Kuthubutheen and A. Nawawi

1918

--I17

10 JIm 10JIm 10 JIm 10 JIm

20 2 1 22 23

1-' tI!'........

I\ I \I I I, , I ...-- , //

I , I / ,.''-- - --"I I /

I - ---,.I --

20 JIm I 20 JIm 20 JIm20 JIm

24/ \

..." \\

\ ,III

_-/ I/

III II, I,

\\

.// /20 JIm \

Figs 16-27. Figs 16-22. Conidia of W. conjunctosporus. Fig. 17. Apical cell arrowed. Fig. 18. Intermediatecells in conidial chain. Fig. 19 Basal cell arrowed. Figs 23-27 Conidia of W. laurinus.

624 Wiesneriomyces conjunctosporus sp, nov.

conidial chains cylindrical, (14-) 18-20 (-25) #m-x (3'5-) 4'5-5 (-6) #m; mostly only one conidialchain produced from each conidiogenous cell.

Conidia germinate readily on CMA. Germ-tubes are produced from each end and also fromany of the cells in the chain. Colonies are ofmoderate growth, at first pale, later becoming darkbrown to nearly black. Mycelium mostly sub-merged, aerial mycelium sparse. Sporulation abun-dant, appearing as white dots in concentric circleson the agar surface. Conidial masses are alsoproduced below the agar surface. Sporodochia(complete with setae) formed on the agar arecomparable to those formed on the natural sub-strate.

Ellis (1971) described W. javanicus as havingconidia in chains of up to 15 cells, with individualcells mostly 10-12 #m long x 3-4'5 #m wide. Heobserved that 'some of the collections seen havemuch smaller conidia and may be different'.Manotis & Strain (1968) described W. javanicusfrom Panamanian soil having conidial chains of 6--8cells measuring 58-73'5 #m long x 2'2-3'7 #mwide and the individual cells 2'8-11'2 #m long.Wiesneriomycesjavanicus described by Matsushima(1975) produces (5-) 7-8 (-9)-celled conidialchains measuring (45-) 62-75 (-85) #m longx 2'5-4 #m wide in culture and 7-8-celled conidialchains measuring 50-60 #m long x 3'5-4 #m wideon the natural substratum. Our own collection ofW. laurinus (IMI 318660) (Figs 12-15, 23-27)produces 7-9-celled conidial chains measuring60-90 #m long with individual cells 9-11 #m longx 3-3'5 #m wide on the natural substratum. Fromthe various descriptions of W. laurinus, it isapparent that the number of cells in the conidialchain usually varies between 5-8 cells while thesize of the individual cells which may be 8-12 #mlong x 3-4 #m wide appears to be consistent formost isolates.

Wiesneriomyces conjunctosporus differs fromW. laurinus in several respects. Generally theconidiomata of W. laurinus are smaller with shortersetae than those of W. conjunctosporus. Setae of W.laurinus are incurved around the conidial masswhereas those of W. conjunctosporus are erect andstraight.

The conidial mass of W. laurinus is usually cup-shaped with a flat top and has been variouslydescribed as yellowish, yellowish brown, goldenyellow to olivaceous. The conidial mass of W.conjunctosporus is broadly conical with a roundedtop and is slightly coiled in a partial to single helix.The conidial mass is invariably white and some-times with a tinge of brown with orange.

The conidia of W. laurinus as discussed aboveare up to 90 #m long so that their greatest length is

only about one-third or a fourth of the length ofthat of W. conjunctosporus (230-360 #m). Theconidial chain in W. laurinus usually comprises 5-8cells while in W. conjunctosporus the numberranges from 15-21, which is about 3 times as many(Figs 16--22). Also, the length of the individualcells in the conidial chain of W. conjunctosporus isabout twice as long as that of W. laurinus. Both theapical and basal cells of the conidial chain in W.laurinus are conical to obclavate and the chaintapers at both ends. In W. conjunctosporus, how-ever, only the apical cell is conical to obclavatewhile the basal cell in the conidial chain iscylindrical to rod-shaped.

Conidiogenesis in both species is holoblastic.Conidia are produced in acropetal succession byrepeated budding accompanied by isthmus forma-tion between successive cells. In W. laurinus,however, the conidiophore is branched regularlyand the terminal branches bearing the conidio-genous cells often occur in groups of 3. Up to 3conidial chains may be formed simultaneouslyfrom each conidiogenous cell. Upon release of theconidial chains, the conidiogenous cells aremarkedly denticulate. In W. conjunctosporus, theconidiophore branching is irregular, often inalternate steps and the conidiogenous cells do notoccur in penicillate clusters. Invariably only oneconidial chain is formed from the tip of eachbranch bearing the conidiogenous cells. Spentconidiogenous cells are somewhat truncate torounded with slightly thickened scars.

The authors are grateful to the University ofMalaya for a research grant to study litter-inhabiting fungi in Malaysia.

REFERENCES

ELLIS, M. B. (1971). Dematiaceous Hyphomycetes. Kew,England: Commonwealth Mycological Institute.

KIRK, P. M. (1983). New or Interesting Microfungi. X.Hyphomycetes on Laurus nobilis leaf litter. Mycotaxon18, 259-298.

KIRK, P. M. (1984). Volutellaria laurina Tassi, an earliername for Wiesneriomyces javanicus Koorders. Trans-actions of the British Mycological Society 8z, 748-749.

KOORDERS, S. H. (1907). Botanische Untersuchungentiber einige in Java vorkommende Pilze, besonderstiber Blatten bewohnende, parasitisch auftretendeArten. 4. Morphologische-Systematisch notizen tibereinige mittel-Javanische, vorwiegend blatterbewohnende Pilze. Verhandelingen der koninklijkenederlandsche Akademie van Wetenschappen(Amsterdam), Section 2, 13, 1-264.

MANOTIS, J. & STRAIN, J. W. (1968). Wiesneriomycesjavanicus from Panamanian soil. Mycologia 60,203-208.

A. J. Kuthubutheen and A. Nawawi 625

MATSUSHIMA, T. (1971). Microfungi of the Solomon Islandsand Papua-New Guinea. Kobe: Matsushima.

MATSUSHIMA, T. (1975). leones Microfungorum aMatsushima Leetorum. Kobe: Matsushima.

MATSUSHIMA, T. (1980). Saprophytic Microfungi fromTaiwan. Part 1. Hyphomycetes. Matsushima Myco-logical Memoirs 1. Kobe: Matsushima Fungus Collec-tion.

SHAW, D. & SUTTON, B. C. (1985). A new aero-aquatichyphomycete from Papua-New Guinea and Australia.Botanical Journal of the Linnean Society 91, 25-36.

SUBRAMANIAN, C. V. (1956). Hyphomycetes - 1.Journalof the Indian Botanical Society 35, 53-91.

(Received for publication 7 September 1987)