A small, tan to orange-buff, fan- or kidney-shaped mushroom that grows in dense overlapping clusters on hardwood logs and stumps. Eastern North American strains are bioluminescent, with the gills glowing faintly green in darkness. It is the type species of Panellus.
Not edible. The fruit bodies are small and have a bitter, acrid or astringent taste; most sources regard it as non-poisonous, but it has a traditional reputation as a strong purgative. Not a food mushroom.
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Habitat
White-rot saprobe in dense clusters on dead logs, stumps and branches of hardwoods such as oak, beech and birch. Fruits mainly in fall, but the tough fruit bodies persist and can be found much of the year.
Distribution
Northern temperate Europe, Asia (including Japan and China), Australia and New Zealand; in North America more common in the east, with a range reaching Alaska and Costa Rica. Luminescence is typical of eastern North American strains; Pacific coast and most non-American strains do not glow.
Characteristics
Cap: up to about 3 cm, semicircular to kidney- or shell-shaped, dry, scurfy to minutely scaly or hairy, dingy whitish to pale brown or orange-buff; margin incurved, sometimes lobed. Gills: narrow, crowded, often forked and cross-veined, pinkish brown to buff; luminescent in eastern strains. Stem: short, lateral to off-center, 0.5-2 cm long, whitish to brownish, hairy; sometimes absent. Spore print: white. Microscopy: spores smooth, elliptical to sausage-shaped, about 3-6 x 2-3 µm, amyloid.
