English: Velvet roll-rim; Velvet rollrim; Velvet-footed pax.
German: Samtfuss-Holzkrempling; Samtfusskrempling.
Name: Latin atrotomentosus, meanis black-haired.
Synonym:
Tapinella atrotomentosa; Agaricus atrotomentosus;
Paxillus atrotomentosus; Rhymovis atrotomentosa; Sarcopaxillus atrotomentosus
Clades:
Tapinellaceae;
Boletales.
Region: North America, Europe, Central America, Costa Rica; Asia, Pakistan, China.
Habitat: on tree stumps of conifers; growing on rotting wood.
Content: atromentin, the brown pigment, chemical defence compound; orange-yellow flavomentins; violet spiromentin pigments; dimeric lactone, bis-osumundalactone; phytoecdysteroids, related to the insect moulting hormone ecdysteroid, paxillosterone, 20,22-p-hydroxybenzylidene acetal, atrotosterones A, B, and C, and 25-hydroxyatrotosterones A and B.
Use: inedible; edible when young; foul bitter, inky flavour, possibly poisonous when old, better form boiling; as a food source in eastern Europe.
MycologyType: squat mushroom; tough and inedible; deterrents of feeding by insects; flesh appetising in appearance; fruiting in summer and autumn; convert chemicals as leucomentins into atromentin, butenolide, osmundalactone when injured.
Spores: small; lack of cystidia; differing basidia.
Stipe: off-centre.
Cap: up to 28 cm across; sepia- or walnut brown; with a rolled rim; depressed centre.
Stem: covered with dark brown or black velvety fur; thick; dark brown; juts out sidewards from the mushroom.
Hymenium: gills are cream-yellow and forked.
Spore print: yellow.
Spores: round to oval; 5 to 6 μm long.