Tomentella qingyuanensis H.S. Yuan & Y.C. Dai, sp. nov.

Index Fungorum number: IF 555772; MycoBank number: MB555772; Facesoffungi number: FoF 05642; Figs. 1, 2, 3

Etymology – Refers to where the type specimen was collected.

Holotype – IFP 019321.

Basidiocarps annual, resupinate, adherent to the substrate, arachnoid, without odour or taste when fresh, 0.1–0.3 mm thick, continuous. Hymenophoral surface smooth or indistinctly granulose, brown to dark brown (7E8–7F8) and concolorous with subiculum when dry. Sterile margin often indeterminate, farinaceous, concolorous with hymenophore. Rhizomorphs present in subiculum and margin, 10–35 μm diam; rhizomorphic surface more or less smooth; hyphae in rhizomorph monomitic, differentiated, of type C, compactly arranged; hyphae in central rhizomorph with both clamps and simple septa, thick-walled, unbranched, 3.5–4.5 μm diam; hyphae at outer part of rhizomorph with both clamps and simple septa, thick-walled, unbranched, 1.5–2.5 μm diam; all the hyphae pale yellow in KOH, cyanophilous, inamyloid. Subicular hyphae monomitic; generative hyphae clamped and simple septate, thin- to slightly thick-walled, occasionally branched, 2–3.5 μm diam, occasionally collapsed, without encrustation, pale yellow in KOH, cyanophilous, inamyloid. Subhymenial hyphae clamped, thin-walled, occasionally branched, 2.5–4.5 μm diam; hyphal cells more or less uniform, pale yellow in KOH, acyanophilous, inamyloid. Cystidia absent. Basidia 20–60 μm long and 5–10 μm diam at apex, 4–7 μm at base, with a clamp connection at base, clavate, stalked, sinuous, without transverse septa, pale yellow in KOH, pale yellow in distilled water, 4-sterigmate; sterigmata 2–5 μm long and 0.3–0.5 μm diam at base. Basidiospores thick-walled, (6–)6.5–7.7(–8)×(5.5– )6–6.9(–7.5) μm, L=6.92 μm, W=6.25 μm, Q=1.07–1.15 (n=60/2), irregularly globose or lobed in frontal view and ellipsoid in lateral view, echinulate, orange in KOH, deep yellow in distilled water, cyanophilous, inamyloid; echinuli usually grouped in 2 or more, up to 1.2 μm long.

Material examined – CHINA, Liaoning Province, Qingyuan County, Experimental Station of Forest Ecology, on rotten angiosperm branch, 10 October 2015, Yuan 10616 (IFP 019321, holotype); Xifeng County, Binglashan National Forest Park, on rotten angiosperm wood debris, 2 August 2016, 11109 (IFP 019322) & 11145.

GenBank numbers – ITS: KY686223, KY686222; LSU: MK446409, MK446410.

Notes – Tomentella maroana Yorou is similar to T. qingyuanensis by having dark brown, continuous basidiocarps adherent to the substrate, a smooth or granulose hymenophore, the presence of rhizomorphs; generative hyphae with both clamped and simple septa and echinulate basidiospores of approximately the same shape. However, the former species is differentiated by crustose basidiocarps, thick-walled subhymenial hyphae and bigger basidiospores with short echinuli (8.5–11×7.5–8.5 μm, Yorou et al. 2011). T. fuscogranulosa resembles T. qingyuanensis by having continuous basidiocarps adherent to the substrate, a smooth or granulose hymenophore, the presence of rhizomorphs, thin- to thick-wall subicular hyphae with both clamped and simple septa and irregularly globose or lobed basidiospores. However, it differs from T. qingyuanensis by having undifferentiated rhizomorphs (type B) and bigger basidiospores (8.0–9.4×7.1–9.0 μm).

Figure 1 – A basidiocarp of Tomentella qingyuanensis (IFP 019321, holotype)

Figure 2 – SEM of basidiospores of Tomentella qingyuanensis (IFP 019321, holotype)

Figure 3 – Microscopic structures of Tomentella qingyuanensis (IFP 019321, holotype). a Hyphae from a rhizomorph. b Section through a basidiocarp. c Basidiospores in frontal view. d Basidiospores in lateral view