Amyloceraceomyces angustisporus S.H. He, sp. nov.

MycoBank number: MB 830033; Index Fungorum number: IF 830033; Facesoffungi number: FoF 06038; Fig. 85

Etymology: Referring to the narrow basidiospores.

Holotype: BJFC 021279.

Basidiocarp Annual or perennial, resupinate, effuse to slight effuse-reflected, separable, without odour or taste when fresh, pellicular to membranaceous, more or less brittle with age and after drying, effuse part up to 15 cm long, 5 cm wide, 1.5 mm thick, stratified; reflected part indistinct and curved after drying, slightly darker than the hymenophore suface. Hymenophore smooth, white, cream to pale yellow, not cracking or sparsely cracking after drying; margin thining out, fimbriate, white or concolorous with hymenophoral surface. Hyphal system monomitic; generative hyphae with clamp connections at all septa. Subiculum distinct, thick, with a loose texture; hyphae in this layer hyaline, thin- to slightly thick-walled, smooth or slight encrusted with small crystals, moderately branched, frequently septate, loosely interwoven, 2–4.5 µm diam. Subhymenium with a rather compact texture; hyphae in this layer hyaline, thin- walled, frequently branched and septate, densely interwoven, more or less agglutinated, 2.5–5.5 µm diam. Cystidia and cystidioles absent. Basidia clavate to subcylindrical, with a basal clamp connection and four sterigmata, 20–32 × 4–6 µm; basidioles similar in shape to basidia, but slightly smaller. Basidiospores narrowly cylindrical to slightly allantoid, hyaline, thin-walled, smooth, amyloid in Melzer’s reagent, 7–10 × (1.8–)2–2.5 µm, L = 8.52 µm, W = 2.15 µm, Q = 3.78–4.16 (n = 60/2).

Material examined: CHINA, Yunnan Province, Binchuan County, Jizushan Forest Park, on dead angiosperm branch, 30 August 2017, He 2844 (BJFC 021279, holotype), He 2819 (BJFC 021256) & He 2824 (BJFC 021260).

GenBank numbers: ITS: MK520873, MK520871, MK520872; LSU: MK491338, MK491337l.

Notes: Amyloceraceomyces angustisporus is charac- terized by the rather long and narrow basidiospores. It is so far the only species of the genus. In the phylogenetic tree, the new species is distantly related to Amylocorticium cebennense (Bourdot) Pouzar (Fig. 84), but the latter species has pure white basidiomata and shorter basidiospores (6.5–7.5 × 1.8–2.2 µm, Bernicchia and Gorjón 2010), and grows on Pinus spp.

Fig. 84 Phylogenetic position of Amyloceraceomyces angustisporus and Amylocorticium ellipsosporum inferred from the ITS and LSU sequences. Bootstrap support values (ML and MP) ≥ 50% and Bayesian posterior probabilities ≥ 0.95 are given near nodes respectively. The tree is rooted with Jaapia argillacea (KHL 11734, CBS252.74) and J. ochroleuca (KHL 8433). The new isolates are in bold.

Fig. 85 Microscopic structures of Amyloceraceomyces angustisporus (BJFC 021279, holotype). a Basidiospores. b Basidia and basidioles. c Hyphae from subiculum