Medium to large agaric, growing on the ground, with a white spore print. Pileus pale, brown, green, blue, grey or black, dry or moist, viscid or glutinous. Lamellae adnexed, adnate or subdecurrent. Stipe central, with a buried pseudorhiza. Partial veil remnants absent. Spores relatively large, hyaline, non-amyloid, smooth; germ pore absent. Cheilocystidia present. Lamellar trama regular. Pileipellis a hymeniderm with pileocystidia. Clamp connections present or absent.

Oudemansiella exannulata grows directly on wood, has a partial veil and lacks a pseudorhiza. Smaller, pale forms of Oudemansiella (other) can be confused with terrestrial species of Mycena, but those lack a pseudorhiza and the pileipellis is not a hymeniderm.

Nine species: Oudemansiella atrocaerulea (= Xerula, Hymenopellis), O. eradicata (= Xerula, Hymenopellis), O. flavo-olivacea (= Xerula, Protoxerula; with var. kimberleyana), O. gigaspora (= Xerula, Hymenopellis, X. radicata var. australis, X. australis [not to be confused with Oudemansiella australis which is a quite separate species]), O. mundroola (= Xerula, Hymenopellis, X. radicata var. mundroola), O. raphanipes (= Xerula, Hymenopellis), O. superbiens (= Xerula, Hymenopellis, X. radicata var. superbiens), O. trichofera (= Xerula, Hymenopellis), O. variabilis (= Xerula, Hymenopellis). Although often reported in older literature, Oudemansiella radicata (= Xerula, Hymenopellis) does not occur in Australia.

W.A., N.T., S.A., Qld, N.S.W., Vic. and Tas.

In native forests, often in open or grassy areas, occasionally in gardens with native plants.

On the ground, but attached to deeply buried wood, or rarely on rotted stumps.

Saprotrophic.

Bougher, N.L. (2009a), Fungi of the Perth region and beyond: a self-managed field book, Western Australian Naturalists' Club (Inc.), Perth. [Description and Illustration of O. mundroola (as Xerula)]

Bougher, N.L. & Syme, K. (1998), Fungi of Southern Australia. University of Western Australia Press, Nedlands. [Description, Illustration and Microcharacters of O. gigaspora (as X. australis)]

Dörfelt, H. (1983), Taxonomische Studien in der Gattung Xerula R.Mre. (VIII), Feddes Repert. 94: 549–561. [Description and Microcharacters of O. superbiens (as X. radicata var. superbiens)]

Dörfelt, H. (1984), Taxonomische Studien in der Gattung Xerula R.Mre. (IX), Feddes Repert. 95: 189–200. [Description and Microcharacters of O. gigaspora (as X. radicata var. australis)]

Fuhrer, B. (2005), A Field Guide to Australian Fungi. Bloomings Books, Hawthorn. [Description and Illustration of O. gigaspora (as X. australis)]

Grey, P. & Grey, E. (2005), Fungi Down Under. Fungimap, South Yarra. [Description, Illustration and Map for O. radicata group]

Grgurinovic, C.A. (1997a), Larger Fungi of South Australia. The Botanic Gardens of Adelaide and State Herbarium and The Flora and Fauna of South Australia Handbooks Committee, Adelaide. [Description, Illustration and Microcharacters of O. mundroola (as X. australis var. mundroola)]

Hood, I.A. (2003), An Introduction to Fungi on Wood in Queensland. University of New England, School of Environmental Sciences and Natural Resources Management, Armidale. [Description and B&W Illustration of O. radicata]

McCann, I.R. (2003), Australian Fungi Illustrated. Macdown Productions, Vermont. [Illustration of O. radicata (as Xerula)]

Pegler, D.N. & Young, T.W.K. (1987), Classification of Oudemansiella (Basidiomycota: Tricholomataceae), with special reference to spore structure, Trans. Brit. Mycol. Soc. 87: 583–602. [Microcharacters of O. gigaspora (as O. radicata var. australis) and O. superbiens (as O. radicata var. superbiens)]

Petersen, R.H. (2008), The genus Xerula (Agaricales; Fungi) in Australia and New Zealand, Nova Hedwigia 87: 1–67. [Description and Microcharacters and often Illustration and/or B&W Illustration of O. atrocaerulea, O. eradicata, O. flavo-olivacea, O. flavo-olivacea var. kimberleyana, O. gigaspora, O. mundroola, O. raphanipes, O. superbiens, O. trichofera and O. variabilis (all under Xerula) and Key to species from Australia and New Zealand (all under Xerula)]

Petersen R.H. & Hughes K.W. (2010), The Xerula/Oudemansiella complex (Agaricales), Beih. Nova Hedwigia 137: 1–625. [Description and Microcharacters and often Illustration and/or B&W Illustration of O. atrocaerulea, O. eradicata, O. gigaspora, O. mundroola, O. raphanipes, O. superbiens, O. trichofera and O. variabilis (all under Hymenopellis) and O. flavo-olivacea and O. flavo-olivacea var. kimberleyana (under Protoxerula) and Key to species worldwide, the Australian species all under Hymenopellis or Protoxerula]

Petersen, R.H. & Methven, A.S. (1994), Mating systems in the Xerulaceae: Xerula, Canad. J. Bot. 72: 1151–1163. [Description, B&W Illustration and Microcharacters of O. gigaspora (as X. australis)]

Shepherd, C.J. & Totterdell, C.J. (1988), Mushrooms and Toadstools of Australia. Inkata Press, Melbourne. [Description and Illustration of O. radicata]

Young, A.M. (2005b), A Field Guide to the Fungi of Australia. University of New South Wales Press, Sydney. [Description and B&W Illustration of O. gigaspora (as X. australis)]