Skeletocutis ochroalba Niemelae , Naturaliste Canadien 112: 466 (1985).

Korhonen, Aku, Seelan, Jaya Seelan Sathiya & Miettinen, Otto, 2018, Cryptic species diversity in polypores: the Skeletocutisnivea species complex, MycoKeys 36, pp. 45-82 : 45

Skeletocutis ochroalba Niemelae, Naturaliste Canadien 112: 466 (1985). Figures 5, 7

Holotype.

Canada. Northern Quebec: Poste-de-la-Baleine, Picea sp., 7 Aug 1982 Niemelä 2695 (H 7017091)

Description.

Basidiocarps annual or possibly perennial; half-resupinate to pileate; up to 3 cm wide and (pilei) up to 8 mm thick; hard when dry but easy to break apart; pilei nodulous or thick but steeply sloping, protruding up to 1 cm; margin of pileus curved downwards, blunt, with narrow, woolly, ridge on the underside; upper surface matted to minutely pubescent, white or cream coloured when young, turning ochraceous brown; pore surface cream coloured with ochraceous or sometimes salmon/peach coloured tints, sometimes a greenish-grey tint is visible in the tubes; context and subiculum finally coriaceous but looser and fibrous near cap edge and surface; context faintly zonate in longitudinal section with thin dark lines separating layers of growth; tube layer up to 1 mm thick, sometimes divided by a thin white layer where tubes are filled with arbuscule-like 'binding hyphae’, otherwise pale buff; pores (6 –)7–8(– 10) per mm.

Hyphal structure: the outer layer of context typically has a loose, fibrous texture composed of radially orientated hyphae. Skeletal hyphae in context / subiculum (1.0 –)2.0–3.5(– 4.0) µm wide, in trama 2.0 –4.6(– 6.2) µm wide, generative hyphae in trama 1.0 –2.2(– 2.9) µm wide.

Basidiospores (2.8 –)2.9–3.7(–4.0)×0.5– 0.8 µm, L=3.1 µm, W=0.67 µm, Q’=3.8–6.0(– 7.0), Q=4.65, n=70/3.

Distribution and ecology.

Boreal North America, possibly quite rare, findings from Northern Quebec and Alberta in Canada; growing on fallen Picea logs.

Specimens examined.

CANADA. Alberta: William A. Switzer Provincial Park, Picea sp., 24 Jul 2015 Spirin 8854a (H); 8854b (H); Northern Quebec: Poste-de-la-Baleine, Picea sp., 7 Aug 1982 Niemelä 2689.

Discussion.

S. ochroalba is most notably distinguished from other North American species of the S. nivea complex by its occurrence on conifer wood. Surface of the pileus is characteristically pubescent in this species. The spores of S. ochroalba are also thicker than those of North American angiosperm-dwelling species apart from S. aff. futilis . Resemblance to the Eurasian conifer-dwelling S. cummata is strong both in phenology and microscopic structure.