Amylocorticium ellipsosporum S.H. He, sp. nov.
Index Fungorum: IF 830033; MycoBank number: MB 830034; Facesoffungi number: FoF 06039; Fig. 1
Etymology – Referring to the ellipsoid basidiospores.
Holotype – BJFC 023898.
Basidiocarp Annual, resupinate, efuse, separable, without odour or taste when fresh, pellicular to membranaceous, up to 10 cm long, 2 cm wide, 0.3 mm thick. Hymenophore smooth, cream to pale orange, not cracking or sparsely cracking after drying; margin thining out, fmbriate, white or concolorous with the hymenophoral surface. Hyphal system monomitic; generative hyphae with clamp connections at all septa. Subiculum distinct, with a loose texture; hyphae in this layer hyaline, thin- to slightly thick-walled, moderately branched, frequently septate, loosely interwoven, 2–4 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, 2.5–4.5 µm diam. Cystidia and cystidioles absent. Basidia clavate, with a basal clamp connection and four sterigmata, 15–20×4–5 µm; basidioles in shape similar to basidia, but slightly smaller. Basidiospores ellipsoid, hyaline, thin-walled, smooth, amyloid in Melzer’s reagent, 3.5–4.5(–5) × 2–2.5(–3) µm, L=3.95 µm, W =2.22 µm, Q=1.78 (n=30/1).
Material examined – CHINA, Fujian Province, Wuyishan Nature Reserve, on rotten trunk of Tsuga chinensis var. tchekiangenesis, 17 August 2016, He 4457 (BJFC 023898, holotype).
GenBank numbers: – ITS: MK520876; LSU: MK491341
Notes – Amylocorticium ellipsosporum is characterized by having cream-colored basidiocarps and small ellipsoid basidiospores. In the phylogenetic tree, A. ellipsosporum formed a strongly supported lineage, sister to A. indicum which is here reported in China for the frst time (Fig. 2). However, A. indicum has large yellow basidiocarps and slenderer basidiospores (4–5×1.7–2.2 µm, Thind and Rattan 1972). A. ellipsosporum is similar to A. mauiense Gilb. & Hemmes by sharing small ellipsoid basidiospores, but the latter species differs in having shorter basidia (12–14 µm) and a distribution in Hawaii and growing on Pinus spp. (Gilbertson and Hemmes 2004).
Figure 2 – 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
Figure 1 – Microscopic structures of Amylocorticium ellipsosporum (BJFC 023898, holotype). a Basidiospores. b Basidia and basidioles. c Hyphae from subiculum