Public Description of Gymnopilus P. Karst.

Title: Public Description
Name: Gymnopilus P. Karst.
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 Draft For Agaricales By Chaelthomas (Private)

Description status: Unreviewed

Taxonomic Classification:

Domain: Eukarya
Kingdom: Fungi
Phylum: Basidiomycota
Class: Agaricomycetes
Order: Agaricales
Family: Hymenogastraceae

General Description:

Pileus 5–27 mm, conical to campanulate becoming more rounded with expansion, circular, dull, pale ferruginous, M 7n5YR’7’10 ; margin entire, becoming slightly reflexed ; pileus surface dull, dry, not hygrophanous, finely but not radially fibrillose. Lamellae broadly adnate with a decurrent tooth, thin, crowded, cream then yellow-cream, at last pale yellow- ferruginous, margin a little paler. Stipe 20–38i2–4 mm, central, circular, equal, with a very pruinose apex continuing well down the stipe with short fine fibrils below, giving a completely white covering throughout; dull-cream to dull- buff, firm to fairly tough, no obvious velar remains. Odour not recorded. Taste bland. Spore print not recorded.

Chemical tests: 5% KOH on pileus surface turns black (jve). Pale yellow pigment diffusing from lamella fragments mounted in 5% KOH. Pigment analysis by TLC confirmed the presence of low levels of bis-noryangonin and hispidin.

Basidiospores [25’2’1], 8n7–9n6i6n0–6n6 (x– l 9n2p0n3i 6n2p0n2) μm, Ql1n47, ellipsoid to amygdaliform, rust- coloured, with a conspicuous, deeper coloured ornamentation, dextrinoid, moderately verrucose, no obvious suprahilar depression although an area of lowered ornamentation is visible in some cases, no germ pore or perisporium. Basidia 30–33i9–10 μm, broadly clavate, four-spored, hyaline, sterigmata to 5 μm. Cheilocystidia 29–36i7–8 μm, lecythiform to tibiiform with long, frequently narrow, necks surmounted by capitellum 3–4 μm diam., rarely septate, terminally thickened, frequently filled with bright, rust-coloured pigment. Pleurocystidia 18–28i4–10 μm, more versiform than cheilo- cystidia, ranging from broadly filamentous to lecythiform with capitellum 3 μm wide, or sphaeropedunculate with slight terminal thickening ; many filled with olivaceous-gold pigment, others hyaline. Hymenophoral trama sub-parallel, consisting of cylindrical hyphae 1n8–6n2 μm diam. with clamp-connections. Caulocystidia 35–55i4–9 μm, tibiiform, with conspicuous capitella 3–4 μm wide, in fascicles at apex and also along length of the stipe, becoming sparse at the base, occasionally filled with golden pigment, mostly hyaline. Pileipellis consisting of an outer layer of lightly encrusted, rust-coloured, radially parallel hyphae 2n5–11n5μm with rounded to finger-like terminal cells; beneath this layer the hyphae are more deeply pigmented and more heavily encrusted. Tramal hyphae pale, straw-coloured, radially parallel. Clamp-connections are obvious on most hyphae. Scanning electron micrographs reveal well demarcated area of lowered ornamentation at suprahilar depression.

Growth habit and habitat: In small groups on wood in wet sclerophyll forest.
Material examined: Australia. Tasmania. Hartz Mtns, A. E. Wood & A. K. Mills, 17 May 1985 (UNSW 85’443, holotype).

The presence of rust-coloured, pigmented pileipellis hyphae, conspicuously ornamented basidiospores 8n7–9n6μm long and capitate, lecythiform to tibiiform pileocystidia is sugges- tive of a close relationship of G. tasmanicus with G. tyallus, G. corticophilus and G. eucalyptorum. G. tasmanicus may be distinguished from the other three species by its overall paler colour, smoother pileus, hairy stipe surface and lack of strong rust-coloured, diffusing pigment. Microscopically G. tasmani- cus has a broader, more discrete ornamentation pattern which is slightly lower in height than G. tyallus and G. corticophilus, and has a prominent suprahilar disc (Fig. 4). Cheilocystidia are infrequently septate, and are not so heavily pigmented as in the other two species. G. tasmanicus is easily separated from G. tomentulosus which has a woolly surface, hyaline pileo- cystidia and less heavily ornamented basidiospores. See G. tyallus for comparison with exotic species.

- Treading the fine line between small-statured Gymnopilus and excentrically stipitate Galerina species in Australia

Description author: Excited delirium [EXD]▼ (Request Authorship Credit)
Description editor: Joseph D. Cohen