Fieldiana Botany, New Series 21: 11. 1989.
Common Name: none
Cap 2.0-4.5 cm broad, convex, expanding to plano-convex, the disc sometimes depressed; margin incurved in youth, edged with fibrils, becoming decurved to plane; surface dry, radially appressed-fibrillose to squamulose, mouse-grey to blackish-grey, paler towards the margin at maturity; context 0.5 cm thick at the disc, rapidly thinning toward the margin, soft, whitish to pale-grey, unchanging; odor and taste mild to faintly farinaceous.
Gills notched, sometimes with a decurrent tooth, adnate to adnexed, close, up to 5.0 mm broad, pale-grey, darker with age, unchanging when injured or bruised; lamellulae in up to three series.
Stipe 2.0-5.0 cm long, 0.5-1.0 cm thick, solid, round, equal or enlarged at the apex and base; surface whitish to ash-grey, fibrillose; partial veil absent.
Spores 6.5-10.0 x 3.5-5.0 µm, elliptical in face-view, slightly inequilateral in profile, smooth, thin-walled; contents granular, hilar appendage inconspicuous, inamyloid; spore print white.
Solitary to scattered in sparse needle duff of montane conifers; fruiting in the spring soon after snow melt; common in most years.
Tricholoma moseri is a small snowbank species, the cap dark-grey, fibrillose to squamulose, with typically notched gills. It superficially resembles a Melanoleuca or Inocybe, but these genera have different spores. Tricholoma spores are smooth, hyaline, and inamyloid, while those of Melanoleuca are hyaline, warted and amyloid. Inocybe spores are dull-brown in deposit, and may be smooth, warted or nodulose. Although unlikely to be confused with Tricholoma moseri, two other Tricholomas are found near melting snowbanks, Tricholoma vernaticum and Tricholoma saponaceum. The former is a large robust mushroom, the cap pale, up to 15.0 cm broad, with a strong cucumber/farinaceous odor, and thin annulus, while the latter has a relatively smooth cap with olive, yellow, grey, and brown tones, and a soapy odor that develops in age. A third Tricholoma, T. myomyces var. cystidiotum could easily be mistaken for T. moseri because of its small size and dark, squamulose cap. It, however, fruits in the fall in coastal forests, and possesses a sparse partial veil as well as smaller spores.
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Singer, R. (1989). New taxa and new combinations of Agaricales. Fieldiana 21: 20-21. (Protologue)