Fibrodontia subaustrosinensis S.L. Liu, S.H. He & L.W. Zhou
MycoBank number: MB 559881; Index Fungorum number: IF 559881; Facesoffungi number: FoF 12861;
Basidiomes annual, resupinate, easily detached, without odor or taste, soft corky and brittle when dry, up to 13 cm long, 3 cm wide and 0.2 mm thick. Hymenophore grandinioid, white to cream when fresh, usually with curry-yellow to olive tinge, olivaceous buff to honey-yellow when dry. Margin white, cottony, up to 0.5 mm wide.Hyphal system dimitic; generative hyphae with clamp connections. Subiculum composed of a loose layer of distinct hyphae; generative hyphae, hyaline, thin- to slightly thick-walled, occasionally branched, smooth, 2–3.5 μm in diam; skeletal hyphae rare, hyaline to yellowish, thick-walled with a wide to narrow lumen, unbranched, smooth, slightly flexuous, 2–3 μm in diam. Aculei composed of a central core of compact hyphae and subhymenial and hymenial layers, at apex terminal hyphae slightly tapered; generative hyphae distinct, hyaline, thin- to slightly thick-walled, occasionally branched, smooth, subparallel, 2–3 μm in diam; skeletal hyphae rare, hyaline to yellowish, thick-walled with a wide to narrow lumen, unbranched, smooth, slightly flexuous, more or less parallel along the aculei, 2–3 μm in diam. Basidia suburniform to clavate, thin-walled, with four sterigmata and a basal clamp connection, 20–27 × 3.8–5 μm; basidioles similar in shape to basidia, but smaller. Basidiospores ellipsoid to ovoid, hyaline, thin-walled, smooth, inamyloid, indextrinoid, acyanophilous, (4.5–)4.8–6 × (3.9–)4–5(–5.5) μm, L = 5.2 μm, W = 4.4 μm, Q = 1.2 (n = 60/2).
Material examined: CHINA, Yunnan, Xichou County, Xiaoqiaogou Forest Park, on fallen angiosperm trunk, 16 Nov. 2019, S.H. He, He 6279 (holotype in BJFC 033223, isotype in HMAS).
Notes: Fibrodontia subaustrosinensis closely resembles F. austrosinensis, but the latter species has shorter basidia (13–16 µm in length) and slightly smaller basidiospores (4.2–5.2 × 3.5–4.5 µm; Liu et al. 2021). Fibrodontia brevidens is also similar to F. subaustrosinensis by the yellowish hymenophore with an olive tinge, but differs in the presence of moderately encrusted skeletal hyphae and smaller basidiospores (4–4.5 × 3.5–4.5 μm; Yurchenko & Wu 2014).
Fig. 1. Basidiomes of Fibrodontia subaustrosinensis (He 6279, holotype). — Scale bars: a = 1 cm; b = 1 mm.
Fig. 2. Microscopic structures of Fibrodontia subaustrosinensis (drawn from the holotype). a. Vertical section of basidiomes; b. Basidia; c. Basidiospores. — Scale bar = 10 μm.