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

Index Fungorum number: IF 900295; Mycobank number: MB 900295; Facesoffungi number: FoF 14058; Figs. 1, 2

Etymology – tasmanicus (Lat.) referring to the type locality Tasmania.

Holotype – LWZ 20180515–17 (HMAS).

Diagnosis – Characterized by annual, resupinate, adnate basidiomes, smooth, white to cream hymenophore, fusoid cystidia with subulate apex, subcylindrical basidia, and broadly ellipsoid basidiospores.

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

Hyphal system monomitic; generative hyphae with clamp connections, hyaline, dichotomous branching, interwoven, thin-walled, 2–3.5 μm in diam, without encrustation. Cystidia fusoid with tapering apex, 25–30×3.5–4 μm. Basidia subcylindrical and constricted, with four sterigmata and a clamp connection at the base, 32–35×4.5–6 μm; basidioles subclavate to suburniform, 13–20×4.5–5.5 μm. Basidiospores broadly ellipsoid, usually with an oily drop, hyaline, smooth, thin-walled, IKI–, CB–, 5–5.4(–5.5)×4–4.7(–4.8) μm, L=5.25 μm, W=4.36 μm, Q=1.20 (30/1).

Material examined – Australia, Tasmania, Tahune Adventures, The look-in look-out, on fallen twig of angiosperm, 15 May 2018, L.W. Zhou, LWZ 20180515–17 (HMAS, holotype).

GenBank number – ITS=OQ540900, LSU=OQ540860.

Notes – Lyomyces tasmanicus has a close relationship with L. crystallina from a phylogenetic perspective (Fig. 3). These two new species also have similar morphological characters, except that L. crystallina has encrusted generative hyphae and narrower basidiospores (3.1–3.4 µm). Lyomyces organensis resembles L. tasmanicus for sharing annual, resupinate, adnate basidiomes and fusoid cystidia. However, L. organensis differs in its crystalline hyphal system, and ellipsoid to narrowly ellipsoid, thin- to slightly thick-walled, narrower basidiospores (2.5‒3.5 µm in width, Yurchenko et al. 2017). Lyomyces bambusinus is also similar to L. tasmanicus by its annual, resupinate, adnate basidiomes, white to cream hymenophore, and fusoid cystidia, but it differs in the presence of capitate cystidia, thick-walled basidiospores and the growth on bamboo (Chen and Zhao 2020).

Figure 1 – Basidiomes of Lyomyces tasmanicus (LWZ 20180515–17, holotype)

Figure 2 – Microscopic structures of Lyomyces tasmanicus (LWZ 20180515–17, holotype). a Basidiospores. b Basidia. c Cystidia. d Basidioles. e Section through a basidiomes. Scale bars: a=5 μm, b–e=10 μm

Figure 3 – Phylogram generated by the maximum likelihood algorithm based on combined nLSU and ITS sequence data is presented along with the bootstrap values and the Bayesian posterior probabilities above 50% and 0.8, respectively, at the nodes. Type specimens are in bold and the isolates of new species characterized are in blue