Small to medium agaric, growing on the ground with rusty to ochre-brown spore print. Pileus brown with covering of dense, radial, paler fibres, not viscid. Lamellae adnexed, adnate or sinuate or notched. Stipe central. Partial veil remnants a ring zone. Spores pale or yellow-brown, very finely warty (can appear smooth); plage absent; germ pore absent. Cheilocystidia present. Lamellar trama regular. Pileipellis a cutis or trichoderm, with a thick-walled hyphae. Clamp connections present.

The pileus is covered by very characteristic dense, pale, radial fibrils over the orange-brown background colour, and the stipe is conspicuously pale-fibrillose. It is differentiated from smooth-spored Inocybe by the absence of metuloids and the very fine spore ornamentation. Some Psathyrella species have a densely radially fibrillose pileus, but the spore print is blackish and the spores are smooth.

One species: Cortinarius fibrillosus (= C. cystidiocatenatus, Inocybe fibrillosa, I. austrofibrillosa, I. cystidiocatenata). Keyed out separately from other Cortinarius due to the very fine spore ornamentation. When the ornamentation is overlooked, the spores appear smooth, which explains why the species has been placed by some authors in Inocybe.

Cortinarius fibrillosus Cleland, Trans. & Proc. Roy. Soc. S. Australia 52: 222 (1928).

W.A., S.A., Qld, Vic. and Tas. (and probably also N.S.W.).

In native forests.

On the ground.

Ectomycorrhizal.

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 C. fibrillosus (as I. austrofibrillosa)]

Fuhrer, B. (2005), A Field Guide to Australian Fungi. Bloomings Books, Hawthorn. [Description and Illustration of C. fibrillosus (as Inocybe austrofibrillosa)]

Gasparini, B. (2006), Renaming of three Australian Cortinarius, Australas. Mycol. 25: 24–27. [Illustration, Description and Microcharacters of C. fibrillosus (as C. cystidiocatenatus)]

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 and Microcharacters of C. fibrillosus (as Inocybe fibrillosa and as I. cystidiocatenata, for which there is also an Illustration)]

Matheny, P.B. & Bougher, N.L. (2010), Type studies of Australian species of Inocybe (Agaricales), Muelleria 28: 87–104. [Description and Microcharacters for C. fibrillosus]

McCann, I.R. (2003), Australian Fungi Illustrated. Macdown Productions, Vermont. [Illustration of C. fibrillosus]