Porostereum spadiceum

A very abundant species occurring on decaying dead wood on the ground, especially of Fagus or Quercus, with resupinate to effused-reflexed basidiomata, concentrically zonate and slightly hirsute caps, a greyish-brown to reddish-brown hymenium with a whitish margin, and coriaceous flesh up to 2 mm thick.

Hyphal system dimitic: skeletal hyphae thick-walled, 5 to 6 µm wide, aseptate, with brownish intracellular pigment; generative hyphae hyaline, moderately thick-walled, 4 to 5 µm wide, septate with clamp connections.

Pseudocystidia originating from skeletal hyphae, very thick-walled, brownish to hyaline, encrusted with crystals in mature basidiomata, projecting considerably (40 to 50 µm) beyond the basidia.

Basidia cylindrical-clavate, 20 to 30 µm long, 4 to 6 µm wide, clamped at the base, 4-spored.

Spores ellipsoidal to oblong, smooth, hyaline, thin-walled, 6 to 7.5 µm long, 3.5 to 4.5 µm wide, with an inconspicuous apiculus at one end, homogeneous inside without evident guttules, inamyloid in Melzer's reagent.