Cap 2.5-8 cm broad, convex, broadly convex to nearly plane in age, often with a low umbo; margin incurved becoming decurved; surface squamulose, the squamules often raised at the disc, appressed near the margin or merely fibrillose, senescing to nearly glabrous; color: dull vinaceous-purple, soon fading to vinaceous-brown to dull brownish-pink; flesh firm, whitish, vinaceous-purple adjacent the cuticle and gills, flesh thin at the margin, moderately thick at the disc; odor, indistinct to faintly farinaceous; taste, bitter.
Gills notched to uncinate, close, moderately broad, at first cream-buff with a pinkish tinge, becoming yellow ochraceous-buff, finally bright orange-brown from maturing spores.
Stipe 2-8 cm long, 0.5-1.5 cm thick, more or less equal to slightly enlarged at the base, hollow to stuffed at maturity; surface appressed fibrillose-striate, colored like the cap with intervening pallid streaks, veil evanescent, fibrillose, cream-buff, leaving a fibrillose annular zone near the apex or fragments on the young cap; buff-colored mycelium at the base.
Spores 6-8 x 3.5-5 µm, elliptical, roughened, dextrinoid; spore print bright orange-brown.
Gregarious to clustered in wood chips, and downed wood of both deciduous and conifers; fruiting from late fall to mid-winter.
Mildly hallucinogenic according to Stamets.
This handsome wood rotter has a vinaceous-purple to vinaceous-brown, squamulose cap, often with scattered dull-green spots. Though Smith & Hesler in their monograph of Gymnopilus did not mention the latter feature in their description, Stamets has observed that the green color can develop under low temperature. We originally believed our collections to be Gymnopilus aeruginosus because of the green stains, but have concluded that overall they are a bettter match for G. luteofolius, especially the the veil, cap color, and cap flesh characters. In Gymnopilus luteofolius the veil is fibrillose-membranous and the cap flesh whitish to vinaceous-purple while in G. aeruginosus the veil is merely fibrillose and the cap flesh tends to be tinged green. A look-alike species for Gymnopilus luteofolius is Tricholomopsis rutilans. It is similarly colored, also grows on wood, but can be distinguished by a white spore print and the lack of a veil.