Notes and brief articles

of its conidia and also by the fact that the latter hasslightly smaller conidia (22-35 x 15-20 pm) in size.

I am deeply grateful to Professor J. Webster,University of Exeter, for helpful advice and MrH. W. Stubbs for the Latin diagnoses .

REFERENCES

ABDULLAH, S. K. (1980). British aero-aquatic fungi.Ph.D. Thesis, University of Exeter.

ABDULLAH, S. K. & WEBSTER, ] . (1980). Occurrence ofaero-aquatic fungi in soil. Transactions of the BritishMycological Society 75, 511-514.

ABDULLAH, S. K. & WEBSTER, ]. (1981). Lambertellatubulosa sp .nov., teleomorph of Helicodendron tubulo-sum. Transactions of the British Mycological Society 76,261-263·

ABDULLAH, S. K., FISHER, P.]. & WEBSTER, ] . (1979).Two new species of aero-aquatic hyphomycetes.Transactions of the British Mycological Society 72,324-329·

BEVERWIJK, A. L. VAN (1953). Helicosporous Hypho-mycetes. 1. Transactions of the British MycologialSociety 36, 111-124.

GLEN-BoTT, ] .1. (1951). Helicodendron giganteum n.sp.and other aerial sporing hyphomycetes of submergeddead leaves. Transactions of the British MycologicalSociety 34, 275-279.

GLEN-BoTT, ]. I. (1955). On Helicodendron tuoulosumand some similar species. Transactions of the BritishMy cological Society 38, 17-30.

LINDER, D . H. (1929). A monograph of the helicosporousfung i imperfecti. Annals of the M issouri BotanicalGarden 16, 227-388.

PEYRONEL, B. (1918). Micromiceti di Val Germanasca,quarto contributo alia flora micologica della ValliValdesi del Piemonte. Nuooo Giornale Botanico ItalianoN .S. 25, 405-464·

VARGHESE, K . 1. & RAo, V. G . (1980) . Two undescribedspecies of dematiaceous hyphomycetes. NorwegianJournal of Botany 37, 55-57.

NEW SPECIES OF VESICULAR-ARBUSCULAR MYCORRHIZAL FUNGI

BY K. G. MUKERJI AND M. BHATTACHARJEE

Department of Botany, University of Delhi, Delhi-t iooor, India

AND J. P. TEWARI

Department of Plant Science, University of Alberta, Edmonton, Alberta, Canada T6G 2PS

Two new species of VAM fungi, Glomus delhiense and G. multisubstensum, are describedfrom India.

Since vesicular-arbuscular mycorrhizal (VAM)fungi may vary considerably in their reaction todifferent plant and soil conditions, the ir properapplication to further plant productivity willrequire that they be taxonomically characterized(Trappe, 1982). The discussion on 'Future Direc-tions and Priorities in Mycorrhizal Research'during the 1982 Annual Meeting of the AmericanPhytopathological Society held at Salt Lake City,Utah also recognized taxonomic characterization ofthe VAM fungi as one of the priority objectives.This is one of a series of communications to furtherthis goal and reports two new species of GlomusTul. & TuI. Both were isolated by the wet-sievingand decanting method (Gerdemann & Nicolson,1963) from soils collected from the Old DelhiRidge, Delhi, India which is a natural forest stand.

The spores were studied by light and scanningelectron microscopy (SEM). For SEM the air-driedspores were vapour-fixed with osmium tetroxide,mounted on stubs with conductive carbon paint,

coated with gold and examined in a CambridgeStereoscan 150 SEM.

Glomus multisubstensum sp.nov. (Figs 1-4)

Chlamydosporae singulatim vel in solo vel in glomer-aminibus densis, 5-8 sporas continentibus, efformatae,globosae, pallide brunneae, 100-150 pm diam, tunicasporarum ltr-15 pm crassa, duabus stratis inseparabilibuscons istans; tunica externa 1tr-12 pm crassa, brunnea;tunica intema 1-4 pm crassa, pallide luteo-brunnea.Hyphae sustinentes 2-4 numero, in termino altero sporaecolligatae, hyalinae, pallide fiavae, tenuitunicatae, propelocum colligationis ltr-15 pm crassae, deinde ad 5-7 pmfastigatae, septum aliquando praesens, 2tr-25 pm sec-undum hyphas sustinentes nonnumquam ramosas.

Chlamydospores formed singly in the soil or incompact clusters of 5 to 8 spores, globose, lightbrown, 100-150 pm diam; spore wall 10-15 pmthick, with two inseparable layers; outer layer10-12 pm thick, brown; inner layer 1-4 pm thickand pale yellow brown. Subtending hyphae 2 to 4 innumber, attached at one end of the spore, hyaline,

Trans . Br. mycol . Soc. 81 (3) (1983)21

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Notes and brief articles

3

6

Figs 1-4. Glomus multisubstensum. Figs 1, 2 SEM; Figs 3, 4 light micrographs. Chlamydospores with multiplehyphal attachment at one end of the spore. 1 x 450; 2 X 600; 3, 4 x 550.

Figs 5---6. Glomus delhiense. Figs. 5 SEM; Fig. 6 light micrograph. Chlamydospores with single hyphalattachment. In Fig. 5 the subtending hypha is broken off revealing the point of attachment. 5 x 550; 6 x 300.

Trans. Br. mycol. Soc. 81 (3) (1983) Printed in Great Britain

Notes and brief articles 643pale-yellow, thin walled, 10-15 pm wide at thepoint of attachment, tapering to 5-7 pm width,septum present in some cases, 20-25 pm along thesubtending hyphae which may be branched.

This species was consistently isolated from OldDelhi Ridge soil from near the roots of Maeruaarenaria H. f. & T. (Capparidaceae). It was veryabundant in February 1980 but declined innumbers during the summer months. Experimen-tally this species formed VAM with Zea mays L. inpot cultures. The holotype specimen is depositedin the Mycological Herbarium of the University ofDelhi as DU/KMB500.

Two species of Glomus (G. multicaule Gerdem.& Bakshi and G. lacteum Rose & Trappe) havespores sometimes with 3 or more subtendinghyphae (Trappe, 1982). Glomus multisubstensum isclearly distinguishable from G. multicaule (Gerde-mann & Bakshi, 1976) in having globose, smooth-walled spores, with multiple hyphal attachmentsbeing always present on one end of the spore. It canbe distinguished from G. lacteum (Rose & Trappe,1980) in having light brown spores with two walllayers.

Attempts were made to study the development ofthe spores, but it was not possible to determinewhether the spores were zygosporic or chlamydo-sporic. Until the life cycle is established it would bebest to assign it to the genus Glomus.

Many spores ofG. multisubstensum revealed signsof hyperparasitism. In surface views perforationsin the cell wall were seen (Fig. 2), while in thesectional views transverse fissures were seen. Inthese respects the mode of hyperparasitism ap-peared to be similar to that described for Gigasporacandida Bhattacharjee, Mukerji, Tewari & Skoro-pad (Bhattacharjee et al., 1982).

Glomus delhiense sp.nov. (Figs 5,6)Chlamydosporae Iibere in conglomerationibus raris insolonatae,globosae, 1ocr-US pmcrassae,tunicasporarumduplex; tunica externa 5-7 pm crassa, luteo-brunnea,cum laminis et leviter asperata; tunica interna 5pmcrassa, hyalina, hyphae sustinentes simplices usque ad15 pm crassae propelocumcolligationis, tunicatransversapraesens vel in forarnine ipso vel 25-30 pm secundumhyphas sustinentes. Cytoplasmsgranulare,

Chlamydospores borne freely in loose aggregates inthe soil, globose, 100-125 pm; spore wall double;outer layer 5-7 pm, yellowish brown, laminate andslightly roughened; inner layer 5 pm, hyaline.Subtending hyphae simple, up to 15 pm wide at thepoint of attachment, with a cross wall present either

at the pore itself or 25-30 pm along the subtendinghypha. Cytoplasm granular.

This species was isolated during February to July1980 from soil from a grassy area in the Old DelhiRidge. In pot cultures it formed VAM withTrigonella foenum-graecum L. (Leguminosae). Theholotype specimen is deposited in the MycologicalHerbarium ofthe University of Delhi as DU/KMB499·

In the genus Glomus, only one species (G.magnicaule Hall) is known to possess spores withouter brown and inner hyaline wall layers(Trappe, 1982). Thickness of the outer spore walllayer and that of the subtending hypha clearlydistinguish G. delhiense from G. magnicaule (Hall,1977). According to Hall & Fish (1979), G. delhiensekeys out to Type 8 but differs in having a simple,instead of an infundibuliform, hyphal attachment(Sward et al., 1978).

Thanks are gratefully acknowledged to Mr G.Braybrook, Department of Entomolgy, Universityof Alberta for helping with use of the SEM and toMr M. Hertwig-Jaksch of the Department ofClassics, University of Alberta for the Latindescriptions.

REFERENCES

BHATTACHARJEE, M., MUKERJI, K. G., TEwARI, J. P. &SKOROPAD, W. P. (1982). Structure and hyperpara-sitismofa newspecies of Gigaspora. Transactions of theBritish Mycological Society 78, 184-188.

HALL, I. R. (1977). Species and mycorrhizal infections ofNewZealandEndogonaceae. Transactions of the BritishMycological Society 68, 341-356.

HALL, I. R. & FISH, B. J. (1979). A key to theEndogonaceae. Transactions of the British MycologicalSociety 73, 261-27°.

GERDEMANN,J. W.&BAKSHI,B. K. (1976). Endogonaceaeof India: two new species. Transactions of the BritishMycological Society 66, 340--343.

GERDEMANN, J. W. &NICOLSON, T. H. (1963). Sporesofmycorrhizal Endogone species extracted from soil bywet sieving and decanting. Transactions of the BritishMycological Society 46, 235-244.

ROSE, S. L. & TRAPPE, J. M. (1980). Three newendomycorrhizal Glomus spp, associated with actinor-rhizal shrubs. Mycotaxon 10,413-420.

SWARD, R. J., HALLAM, N. D. &HOLLAND, A. A. (197 8).Endogone spores in a heathland area of south-easternAustralia.Australian Journal of Botany %6, 29-43.

TRAPPE, J. M. (1982). Synoptic keys to the genera andspecies of zygomycetous mycorrhizal fungi. Phyto-pathology 7%, 1102-1108.

Trans. Br. mycol. Soc. 81 (3) (1983) Printed in Great Britain