Athelopsis subglaucina S.L. Liu & L.W. Zhou, sp. nov.

Index Fungorum number: IF 901055; Mycobank number: MB 901055; Facesoffungi number: FoF 1480; Figs. 1, 2

Etymology: subglaucina (Lat.) referring to the similarity to A. glaucina.

Holotype: LWZ 20180512–13 (HMAS).

Diagnosis: Differing from A. glaucina in whitish to ashgray basidiomes and wider basidiospores (Eriksson and Ryvarden 1973; Bernicchia and Gorjón 2010).

Basidiomes resupinate, effused, thin, loosely adnate, up to 12 cm long, 3 cm wide, 100 µm thick. Hymenophore smooth, continuous, whitish to ash-gray when fresh, grayish when dry, not cracked. Margin thinning out, concolorous.

Hyphal system monomitic; generative hyphae with clamp connections, hyaline, thin-walled, frequently branched, 2–3 µm. Cystidia absent. Basidia clavate, 14–16×6–7 µm, with four sterigmata and a basal clamp connection. Basidiospores cylindrical, some narrowed toward the apex, hyaline, thin-walled, smooth, IKI–, CB–, 8.5–10 ×2.5–3 µm, L=9 µm, W=2.6 µm, Q=3.5 (n=30/1).

Material examined – Australia, Victoria, Yarra Ranges National Park, Dandenong Ranges Botanic Garden, on fallen branch of Eucalyptus, 12 May 2018, L.W. Zhou, LWZ 20180512–13 (HMAS, holotype).

GenBank numbers – ITS=OR557255, LSU=OR527279.

Notes – Athelopsis subglaucina is morphologically similar to A. glaucina and these two species have a close phylogenetic relationship (Fig. 3). However, A. glaucina differs in yellowish basidiomes and narrower basidiospores (2–2.5 µm in width; Eriksson and Ryvarden 1973; Bernicchia and Gorjón 2010).

Figure 1 – Basidiomes of Athelopsis subglaucina (LWZ 20180512–13, holotype). Scale bars: a=1 cm, b=1 mm

Figure 2 – Microscopic structures of Athelopsis subglaucina (LWZ 20180512–13, holotype). a A vertical section of basidiomes. b Basidiospores. Scale bars: 10 μm

Figure 3 – Phylogeny generated by the maximum likelihood algorithm based on combined ITS and nLSU regions is presented along with the bootstrap values and the Bayesian posterior probabilities above 50% and 0.8, respectively, at the nodes. Coniophora marmorata MUCL 31667 and Pseudomerulius aureus FP-103859 were selected as the outgroup taxa. Holotypes are in bold and the newly generated sequences are in blue