Lyomyces crystallina Xue W. Wang & L.W. Zhou, sp. nov.

Index Fungorum number: IF 900296; Mycobank number: MB 900296; Facesoffungi number: FoF 14059; Figs. 1, 2

Etymology – crystallina (Lat.) referring to crystalline materials covering generative hyphae.

Holotype – LWZ 20190810-6b (HMAS).

Diagnosis – Characterized by annual, resupinate, adnate basidiomes, smooth to slightly grandinioid, cream to pale buff hymenophore, fusoid cystidia with subulate apex, subcylindrical basidia, and narrowly ellipsoid to oblong basidiospores.

Basidiomes annual, resupinate, adnate, cracked and brittle when dry, without odour. Hymenophore smooth to slightly grandinioid, cream to pale buff. Margin concolorous with subiculum, abrupt.

Hyphal system monomitic; generative hyphae with clamp connections, hyaline, dichotomous branching, interwoven, thin-walled, 2.5–3.5 μm in diam, encrusted with coarse crystalline materials throughout the hymenium. Cystidia fusoid with subulate apex, 20–25×3.5–4 μm. Basidia subcylindrical and constricted, with four sterigmata and a clamp connection at the base, 30–35×5–5.5 μm; basidioles subclavate, 13–20 ×4.5–5.5 μm. Basidiospores narrowly ellipsoid to oblong, usually with an oily drop, hyaline, smooth, thin-walled, IKI–, CB–, (5–)5.1–5.6(–5.7)×3.1–3.4(–3.5) μm, L=5.32 μm, W=3.26 μm, Q=1.63 (30/1).

Materials examined – China, Sichuan Province, Ganzi Tibetan Autonomous Prefecture, Jiulong County, on fallen branch of angiosperm, 10 August 2019, L.W. Zhou, LWZ 20190810-6b (HMAS, holotype).

GenBank number – ITS=OQ540901.

Notes – Lyomyces juniperi resembles L. crystallina for sharing annual, resupinate, adnate basidiomes, slightly grandinioid hymenophore, fusoid cystidia with subulate apex, and ellipsoid basidiospores; however, L. juniperi differs in its larger basidiospores (5–6.5×3.5–4 μm, Langer 1994).

Figure 1 – Basidiomes of Lyomyces guttulatus (LWZ 20200921-29a, holotype)

Figure 2 – Microscopic structures of Lyomyces crystallina (LWZ 20190810-6b, holotype). a Basidiospores. b Basidia and basidioles. c Cystidia. d Hyphae from subiculum. e A vertical section of hymenium. Scale bars: 10 μm