Trechispora tropica S.L. Liu & L.W. Zhou.
MycoBank number: MB 559904; Index Fungorum number: IF 559904; Facesoffungi number: FoF 12884;
Basidiomes annual, resupinate, effused, thin, soft and fragile, easily separated from substrates, up to 11 cm long, 5 cm wide. Hymenophore grandinioid to odontioid with numerous, small aculei, white to cream when fresh, cream to straw-yellow when dry. Margin white, fimbriate, up to 2 mm wide. Hyphal system monomitic; generative hyphae with clamp connections. Subicular hyphae hyaline, thin-walled, moderately branched and septate, subparallel, 2.5–6 µm in diam, ampullate septa up to 8 μm wide. Aculei composed of a central core of compact hyphae and subhymenial and hymenial layers; generative hyphae distinct, hyaline, thin or thick-walled, moderately branched, smooth, subparallel, 2.5–5.5 μm in diam; hyphal ends present at apex, cystidium-like, long-celled, 2.5–4 μm in diam. Cystidia absent. Crystals only present in subiculum, bipyramidic, aggregated. Basidia cylindrical with a slight median constriction, hyaline, thin-walled, with four sterigmata and a basal clamp connection, 7–10 × 4–5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores ellipsoid, hyaline, thin-walled, aculeate, inamyloid, indextrinoid, acyanophilous, 2.5–3 × 2.2–2.5(–2.6) µm, L = 2.8 µm, W = 2.3 µm, Q = 1.2 (n = 60/2).
Material examined: CHINA, Hainan, Ledong County, Jianfengling National Forest Park, on fallen angiosperm branch, 13 June 2017, L.W. Zhou, LWZ 20170613-14 (holotype in HMAS).
Notes: Trechispora tropica is phylogenetically close to T. laevis, T. stevensonii and T. taiwanensis (Fig. 6). However, T. laevis differs in smooth hymenophore (Larsson 1996), T. stevensonii in the presence of arthroconidia (Larsson 1995), and T. taiwanensis in longer basidiospores (3–4 µm in length) sometimes with one oil drop in the protoplasm and the growth on bamboo.
Fig. 1. Basidiomes of Trechispora tropica (LWZ 20170613-14, holotype). — Scale bars: a = 1 cm; b = 1 mm.
Fig. 2. Microscopic structures of Trechispora tropica (drawn from the holotype). a. Vertical section of basidiomes; b. Basidia; c. Basidiospores. — Scale bars = 10 μm.