Name: Datronia mollis
Author: (Sommerf.) Donk
Citation: Persoonia 4(3): 338 (1966)
Preferred Synonyms:Cerioporus mollis (Sommerf.) Zmitr. & Kovalenko
Deprecated Synonyms: Daedalea mollis Sommerf., Trametes mollis (Sommerf.) Fr., Polyporus mollis (Sommerf.) P. Karst., Antrodia mollis (Sommerf.) P. Karst., Daedaleopsis mollis (Sommerf.) P. Karst., Cerrena mollis (Sommerf.) Zmitr.
Habitat/range: On hardwoods, causing a white rot. In BC, known from a sin- gle northern collection at Cinema to scattered sites on southern Vancouver Island and the Vancouver area. Elsewhere in western North America, known from AK and AB south to CO. Basidiomata reflexed, occasionally effuse or sessile, annual, leathery; pileus up to 2.5 cm wide × 6 cm long × ~ 0.6 cm thick; pileus surface dark brown to black, strigose to glabrous, concentrically zonate; context up to 1 mm thick, pale buff with a thin black line beneath the dark brown surface tomentum; tubes up to 3 mm deep; pore surface buff to umber brown; pores angular to daedaleoid, 1–2 per millimetre, some over 1 mm wide, edges thin, lacerate.
Generative hyphae 2.5–4.0 μm diameter with clamp connections; skeletal hyphae 2.5–4.0 μm diameter, pale greenish yellow in lower context, darker brown above the black line; binding hyphae 2–3 μm diameter; cystidioles fusoid, 25–45 × 4–5 μm; dendrohyphidia on the pore edges, 1.5–3.0 μm diam- eter with numerous short branches near the apex; basidiospores cylindric to narrowly ellipsoid, 10–12 × 3.0–4.5 μm.
Notes: The black line beneath the tomentum and large, irregular pores dis- tinguishes D. mollis from other provincial species of Datronia. Fuscocerrena portoricensis (Fr.) Ryvarden occurs in Washington on Alnus rhombifolia but has not yet been found in British Columbia. It resembles D. mollis in having a dark brown pileus surface, large pores, and dendrohyphidia but differs in having smaller basidiospores (5–7 × 2.0–2.5 μm). Each of the squares in the scale is 1 × 1 cm.