Xylodon pruinosus (Bres.) Spirin & 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 : 77

Xylodon pruinosus (Bres.) Spirin & Viner comb. nov. Figures 6 a,b, 8, 10, 11

Basionym.

Odontia pruinosa Bres., Annales Mycologici 18 (1-3): 43. 1920. ≡ Lagarobasidium pruinosum (Bres.) Jülich, Persoonia 8: 84. 1974.

Type.

Germany. Nordrhein-Westfalen, Lengerich, W.Brinkmann (lectotype L [L 0053271], designated by Jülich 1974: 84).

= Hyphodontia nikolajevae Parmasto, Conspectus Systematis Corticiacearum: 213. 1968. Type: Estonia. Ida-Virumaa, Kohtla-Järve, Pärnassaare, on Betula pubescens , 1 Oct 1958, E.Parmasto (holotype: TAAM [9683], by original designation).

= Hyphodontia magnacystidiata Lindsey & Gilb., Mycotaxon 5: 315. 1977. Type: USA. New York, Franklin County, Paul Smith’s, on Populus tremuloides , 12 Sep 1965, R.L.Gilbertson 5481 (holotype: BPI [266395], by original designation).

Description.

Basidiocarps annual, resupinate, up to 5 cm in widest dimension. Margin poorly differentiated, pruinose. Hymenial surface greyish-white or pale cream-coloured, grandinioid to odontoid; projections rather regularly arranged, from 100 µm to 250 µm high, 80-100 μm broad at base, 6-8 per mm. Hyphal structure monomitic, hyphae clamped, faintly cyanophilous, thin-walled. Subicular hyphae interwoven and frequently branched, 2.2 –4.7(– 6.1) μm in diam. (n=60/6). Tramal hyphae subparallel, subhymenial hyphae short-celled, 2.0 –3.5(– 3.9) μm in diam. (n=60/6). Stellate crystals abundant in trama, subiculum and subhymenium, 4.4-8.3 μm in diam. Cystidia large, thin-walled, of subicular, tramal or subhymenial origin, clavate to spathuliform, often with an intercalary inflation, sometimes slightly thick-walled (wall not exceeding 1 μm thick), rarely forked, (35.0 –)44.0–84.0(–107.0)×(4.0–)4.9–10.9(– 12.4) μm (n=121/6), occasionally bearing 1-2 clamped septa. Basidia suburniform, 4-spored, (12.0 –)14.0–20.8(–24.0)×3.4–4.2(– 5.5) μm (n=60/6), thin-walled. Basidiospores clearly thick-walled, ellipsoid to broadly ellipsoid, usually with an oil-drop, (4.0 –)4.5–5.9(–7.0)×(3.3–)3.7–4.8(– 5.7) μm (n=192/6), L=5.09, W=4.12, Q=1.24, cyanophilous.

Distribution and ecology.

Europe (Estonia, Finland, Germany, Norway, Russia - up to Ural Mts.), North America, on medium-decayed wood of angiosperms.

Remarks

. The type specimen of Hyphodontia nikolajevae Parmasto reveals no essential differences from the type and other collections of X. pruinosus studied by us. On average, Xylodon pruinosus has wider basidiospores than X. detriticus (Table 2).