Xylodon ussuriensis Viner

Viner, Ilya, Spirin, Viacheslav, Zibarova, Lucie & Larsson, Karl-Henrik, 2018, Additions to the taxonomy of Lagarobasidium and Xylodon (Hymenochaetales, Basidiomycota), MycoKeys 41, pp. 65-90 : 78-81

Xylodon ussuriensis Viner sp. nov. Figure 12

Type.

RUSSIA. Primorie: Khasan Dist., Kedrovaya Pad Nat. Res., on angiosperm wood, 24 Jul 2016, I.Viner KUN 1989* (H) - ITS sequence, GenBank MH324468.

Etymology.

Ussuriensis (lat., adj.) - from the river Ussuri in Russian Far East and adjacent China.

Description.

Basidiocarps effused, up to 10 cm in longest dimension. Sterile margin white to pale ochraceous, floccose, up to 1 mm wide. Hymenial surface pale ochraceous, grandinioid to odontoid; projections rather regularly arranged, from 100 µm to 250 μm high, 90-110 μm broad at base, 6 –8(– 9) per mm. Hyphal structure monomitic, hyphae clamped, faintly cyanophilous, thin-walled. Subicular hyphae interwoven, (3.0 –)3.4– 6.2 μm in diam. (n=30/3). Tramal hyphae subparallel, sub hymenial hyphae short-celled, 1.9-3.9 μm in diam. (n=30/3). Large rhomboid or stellate crystals rarely present in trama and subiculum, 10-19 μm in diam. Cystidia of three types: a) large, thin- or fairly thick-walled (wall up to 2.8 μm thick) cystidia of subicular, tramal or subhymenial origin, cylindrical, spathuliform, almost capitate or with one intercalary inflation at the upper part, (64.0 –)71.0–188.9(–220.0)×(5.0–)5.7–9.4(– 11.9) μm (n=30/3), often apically encrusted by large rhomboid crystals, b) astrocystidia of subhymenial origin, bearing a stellate crystalline cap 15 –17×4.5– 4.8 μm, sometimes rare, c) cystidia of subhymenial origin, thin-walled, varying from fusoid to cylindrical or submoniliform, rarely forked, 40.0 –84.0(–92.0)×5.0–9.0(– 11.4) μm (n=30/3). Basidia suburniform, 4-spored, 14.7 –22.8(–24.0)×3.4– 4.9 μm (n=30/3), thin-walled. Basidiospores clearly thick-walled, ellipsoid to broadly ellipsoid, usually with an oil-drop, (4.8 –)5.1–6.0×3.8– 4.6 μm (n=92/3), L=5.48, W=4.21, Q=1.30, cyanophilous.

Distribution and ecology.

East Asia (Russian Far East - Primorie), on decayed angiosperm wood; seemingly not rare in secondary oak-dominated forest.

Remarks.

The distinctly thick-walled tubular cystidia of X. ussuriensis make it different from other Lagarobasidium -like species treated here. Subhymenial astrocystidia found in X. ussuriensis are also present in some specimens of X. detriticus although they are apparently rare in the latter species.