Fruiting body annual, persistent, sessile, globose to cushion-shaped, occasionally lobed, 1.5-6.5 cm broad, 1-2.5 cm thick; surface smooth, shiny, chestnut-brown to ochraceous-brown, occasionally tinged pinkish at the attachment point, in age unpolished, fading to buff-brown; margin broad, rounded, continuing as a tough, buff-brown to whitish, veil-like membrane over the spore-bearing surface; flesh white, thick, pliant at first, tough in age; tubes 3-5 mm long, pallid becoming buff-brown; pores 3-4/mm.
Spores 8-10 x 3.5-5 µm, smooth, elongate-elliptical; spore print pinkish-buff.
Scattered to grouped on standing dead conifers or fallen timber; fruiting from mid to late winter.
Too tough to considered for the table.
This unusual polypore looks like a puffball growing on wood. However, sectioning the woody fruiting body (a sturdy blade or saw is required) reveals an internal tube layer typical of polypores. Insects, mostly beetles, help disperse the spores by chewing holes in the veil-like membrane that covers the tube layer and by carrying spores to other dead trees.