White-gray, thin, powdery, easily detachable crust growing on the underside of a well-decayed log ~30cm wide, perhaps tanoak.

Basidia with 2-6 sterigmata, 16-21 × 7-10. Spores 6.5-8 × 3-4, inamyloid. Subhymenial hyphae 5-7 microns wide, basal hyphae up to 10 microns. No clamps.

Langer’s key leads to B. robustior (= _B. rubiginosum). The key in Bernicchia & Gorjon leads to a group of 4 species (including B. robustius) with a remark that the distinction between them requires examination of anamorph. -I didn’t see (or didn’t recognize) conidia

In all of the several mounts I made, there were also some dark thick-walled septate and branched hyphae, 3.5-5 microns wide. Can they be unrelated to this crust?


Lots of spores on one basidium.
Mysterious dark hyphae mixed with generative hyphae in all mounts. At 10×.
Same, 40×.
Same, 100×. Thick-walled basal hyphae at the bottom (~10 microns).

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