Public Description of Gymnopus billbowesii Desjardin & B.A. Perry

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Name: Gymnopus billbowesii Desjardin & B.A. Perry
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Description status: Unreviewed

Taxonomic Classification:

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

General Description:

Gymnopus billbowesii is characterized by a small white pileus with brown to greyish orange disc that bruises reddish brown, distant white lamellae, a tough, pruinose stipe white at the apex and reddish brown at the base, raphanoid odor and taste, small ovoid basidiospores (mean 5.8  4.4 μm), irregularly clavate cheilocystidia and caulocystidia, a cutis-type pileipellis, non-dextrinoid tissues with clamp connections, and growth on woody debris.

Diagnostic Description:

Pileus 3–15 mm diam, convex, margin striate to striatulate; surface dull, moist to dry, sometimes rugulose, glabrous to felted, subhygrophanous, disc brown (7–8E5–6) to pale greyish orange (<6B3), margin cream (4A3) to buff or white, in age buff overall or with a small greyish orange disc, often bruising reddish brown. Context <1 mm thick, soft, white. Lamellae adnexed to ascending- adnate with a very short decurrent tooth, distant with 2 series of lamellulae, broad (2–4 mm), white, non-marginate. Stipe 15–25  0.5–1.5 mm, central, terete, cylindrical or narrowed downward, tough, hollow, insititious to subinsititious; surface dull, dry, pruinose, apex white to greyish orange or pale brownish grey (6C2), base brown (6–7E4–5) to dark reddish brown (7–8F6–8). Odor and taste raphanoid.

Basidiospores 5–7  3.8–5 μm [xm = 5.8 ± 0.43  4.4 ± 0.33 μm, Q = 1.2–1.4, Qm = 1.33 ± 0.05, n = 25, s = 1], ovoid to broadly ellipsoid, smooth, hyaline, inamyloid, thin-walled. Basidia 23–32  5.7–8.0 μm, clavate, 4-spored. Basidioles clavate to subcylindrical. Pleurocystidia absent. Lamellar edge fertile. Cheilocystidia scattered, 22–36  8–12 (–20) μm, broadly clavate to irregular, with or without a few apical knobs, hyaline, inamyloid, thin-walled. Pileipellis a cutis of repent, interwoven
hyphae 3–12 μm diam, cylindrical or irregular, branched, non-diverticulate or with broad, knob-like 1386

outgrowths, non-incrusted or with thin hyaline to pale brown incrustations, hyaline, inamyloid, non- gelatinous, thin-walled; terminal cells undifferentiated. Pileus trama interwoven, hyphae 2.5–8 μm diam; lamellar trama regular, hyphae 2–5 μm diam; hyaline, inamyloid, non-incrusted, non-gelatinous, thin-walled. Stipitipellis a cutis with numerous clustered caulocystidia; cortical hyphae 2–6.5 μm diam, cylindrical, non-diverticulate, hyaline to pale brown, inamyloid, thin-walled or with walls up to 0.5 μm thick, non-incrusted, non-gelatinous; medullary hyphae 2–9 μm diam, hyaline, inamyloid, thin-walled. Caulocystidia 20–70  3.5–10 μm, irregularly cylindrical to clavate, sometimes lobed or with a few broad knobs, hyaline to pale brown, inamyloid, thin-walled or with walls up to 0.5 μm thick. Clamp connections present in all tissues.

Habitat and known distribution – Solitary on woody debris under baobab trees and mesquite in coastal xerophytic habitat, or on trunk of standing palm in coastal secondary forest. Africa (São Tomé).

Description author: Excited delirium [EXD]▼ (Request Authorship Credit)