Lilloa 22: 149. 1951.
Common Name: none
Synonyms: Clitocybe mutabilis Bigelow; Hygrophorus angelesianus Smith and Hesler
Cap 1.0-3.0 cm broad, convex, broadly so in age, the disc typically depressed; margin in youth incurved, then decurved to plane, occasionally wavy; surface glabrous, hygrophanous, dark-brown in youth, medium-brown to dingy, rusty-brown in age, reddening with KOH; context pallid, slowly pale-tan when injured; odor not distinctive; taste mild.
Gills close to subdistant, decurrent, occasionally forked, lilac-grey to lilac-brown; lamellulae in up to three series.
Stipe 2.0-4.0 cm long, 0.4-0.8 cm thick, round to flattened in cross-section, stuffed to hollow at maturity, enlarged at the base; surface dark-brown, overlain with white fibrils, tinged violaceus below, the base covered with lilac mycelium; veil absent.
Spores 7.5-9.5 x 4.5-5.5 µm, elliptical in both views, slightly inequilateral in profile, smooth, thin-walled, amyloid, hilar appendage conspicuous; spore print white.
Solitary to scattered in dirt and needle duff of montane conifers; fruiting in the spring near melting snow; occasional; may also occur sporadically in coastal forests after fall rains.
With features that straddle Hygrophorus and Clitocybe, it is not surprising that that there has been uncertainty regarding the affinities of this snowbank mushroom. It is now generally placed in the genus Neohygrophorus, which differs from the above in the combination of cap and gill tissue that redden in KOH and amyloid spores. Neohygrophorus angelesianus can be recognized by its clitocyboid stature, dark-brown, hygrophanous, centrally depressed cap, lilac-tinged, decurrent gills and lilac-colored mycelium at the stipe base. Somewhat similar is Clitocybe atrobrunnea. The latter, however, is a smaller mushroom with a dark-grey cap and gills in age, and a preference for exposed sites, and humus-free soils. Compare also with Laccaria pumila, another montane mushroom similar in shape, but with a reddish-brown to orange-brown cap and flesh-colored, not lilac-tinged gills. Microscopically it differs in having inamyloid, echinulate spores.
Bigelow, H.E. (1977). New Taxa of Clitocybe. Mycotaxon 6(1): 181-185. (PDF)
Bigelow, H.E. (1985). North American Species of Clitocybe. Part II. J. Cramer: Berlin, Germany. 241 p.
Cripps, C.L. (2009). Snowbank Fungi Revisited. Fungi 2(1): 47-53. (PDF)
Hesler, L.R. & Smith, A.H. (1963). North American Species of Hygrophorus. University of Tennessee Press: Knoxville, TN. 416 p.
Largent, D.L. (1985). The Agaricales (Gilled Fungi) of California. 5. Hygrophoraceae. Mad River Press: Eureka, CA. 208 p.
Redhead, S.A., Ammirati, J.F., Norvell, L. & Seidl, M.T. (2000). Notes on western North American snowbank fungi. Mycotaxon 76: 321-328.
Smith, A.H. & Hesler, L.R. (1942). Studies in North American species of Hygrophorus II. Lloydia 5: 1-94.