Trechispora subfarinacea S.L. Liu & L.W. Zhou, sp. nov.

Index Fungorum number: IF 901062; Mycobank number: MB 901062; Facesoffungi number: FoF 14815; Figs. 1, 2, 3

Etymology – subfarinacea (Lat.) referring to the morphological similarity and phylogenetic kinship to Trechispora farinacea.

Holotype – LWZ 20200921-33a (HMAS).

Diagnosis – Differing from T. farinacea in smooth hymenophore and smaller basidiospores (Larsson 1995).

Basidiomes annual, resupinate, effused, thin, soft, easily separated from substrates, up to 20 cm long, 2 cm wide, 50–80 µm thick. Hymenophore smooth, arachnoid, white when fresh, ash-grey to pale mouse-gray when dry, not cracked. Margin white, thinning out as byssoid, 0.2 mm wide.

Hyphal system monomitic; generative hyphae with clamp connections. Subicular hyphae long-celled, hyaline, thin-walled, frequently branched and septate, interwoven, 3–4 µm in diam, ampullate septa up to 5 μm wide. Subhymenium composed of indistinct generative hyphae, much branched. Cystidia absent. Crystals rare, aggregated, rhomboidal flakes. Basidia cylindrical with a slight median constriction, hyaline, thin-walled, with four sterigmata and a basal clamp connection, 10–15×5–6 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores subglobose, hyaline, thick-walled, verrucose, IKI–, CB–, 3–3.5(–3.7) × 2.8–3(–3.1) µm, L = 3.2 µm, W = 2.9 µm, Q=1.1 (n=30/1).

Material examined – China, Sichuan Province, Liangshan Yi Autonomous Prefecture, Leibo County, Mamize Nature Reserve, on fallen branch of Picea, 21 September 2020, L.W. Zhou, LWZ 20200921-33a (HMAS, holotype).

GenBank numbers – ITS=OM523528, LSU=OM339331.

No00tes – Trechispora gracilis is quite similar to T. subfarinacea by thin basidiomes and smooth hymenophore, but differs in cream to light ash-grey hymenophore when fresh and slightly smaller basidiospores (2.8–3.2×2.3–2.8 µm, Liu et al. 2022b).

Figure 1 – Basidiomes of Trechispora subfarinacea (LWZ 20200921- 33a, holotype). Scale bars: a=1 cm, b=1 mm

Figure 2 – Microscopic structures of Trechispora subfarinacea (LWZ 20200921-33a, holotype). a A vertical section of basidiomes. b Basidia. c Basidiospores. Scale bars: 10 μm

Figure 3 – Scanning electron micrograph of basidiospores of Trechispora tuberculata (LWZ 20200921-33a, holotype). Scale bars: 2 μm