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Cystoderma amianthinum

[Basidiomycetes > Agaricales > Tricholomataceae > Cystoderma . . . ]

by Michael Kuo

Perhaps the most widespread and common Cystoderma species worldwide, Cystoderma amianthinum is found with some regularity in northern and montane (including Appalachian) regions of North America. It is usually found growing in moss, under conifers.

Distinguishing physical features for Cystoderma amianthinum include the yellowish brown to yellowish cap; the dense coating of granules on the cap and stem; the fragile and ephemeral (rather than sturdy and persistent) ring; the usually pungent odor; and the reddish to reddish brown reaction of the cap surface to KOH. Under the microscope, Cystoderma amianthinum has amyloid spores and pileipellis elements that are rusty brown in KOH.

A whitish version, variously labeled as a "form" or "variety" with the epithet alba, has now been reduced to synonymy with the typical Cystoderma amianthinum; the same is true of form/variety rugosoreticulatum, characterized by a dramatically wrinkled-reticulate cap. The Siberian variety/form olivaceum, which has an olive cap when young, is still a valid taxon according to the Index Fungorum--but this is probably because it has been overlooked or unavailable for study by recent investigators.

Cystoderma jasonis (illustrated) is the current name for two taxa that were previously known as varieties of Cystoderma amianthinum (var. longisporum and var. sublongisporum). According to Harmaja (1979), Cystoderma jasonis has a darker brown cap and stem with slightly larger granules, a sometimes purple stem apex, and slightly larger spores (6-7.5 x 3-4.5 µ).


Ecology: Saprobic; growing alone, scattered, or gregariously, usually in moss under conifers; late summer and fall (over winter in California); widely distributed in northern and montane North America.

Cap: 2-5 cm; dry; convex, obtusely conic, or bell-shaped at first, becoming broadly convex, broadly bell-shaped, or nearly flat; frequently somewhat wrinkled in radial patterns (strikingly so in one version); covered with mealy granules; pale reddish brown to yellowish brown or yellowish.

Gills: Attached to the stem; close; whitish becoming pale yellowish.

Stem: 3-7 cm long; 3-8 mm thick; more or less equal, or tapering to apex; dry; pale and fairly smooth near the apex, but sheathed with granular material and colored like the cap below; the sheath terminating in a flimsy ring that often fragments or disappears.

Flesh: Whitish; thin.

Odor and Taste: Taste mild; odor usually pungent and unpleasant.

Chemical Reactions: KOH on cap surface rusty red.

Spore Print: White.

Microscopic Features: Spores 4-7 x 3-4 µ; elliptical; smooth; at least weakly amyloid. Cystidia absent. Pileipellis elements with rusty brown walls in KOH; chained together; inflated; subglobose.

REFERENCES: (Scopoli, 1772) Fayod, 1889. (Saccardo, 1887; Smith & Singer, 1945; Harmaja, 1979; Smith, Smith & Weber, 1979; Arora, 1986; Lincoff, 1992; Barron, 1999; McNeil, 2006; Miller & Miller, 2006.) Herb. Kuo 09010607.

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Cystoderma amianthinum

Cystoderma amianthinum

Cystoderma amianthinum

Cystoderma amianthinum

Cystoderma amianthinum

Cystoderma amianthinum

Cystoderma jasonis
Cystoderma jasonis

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Kuo, M. (2007, February). Cystoderma amianthinum. Retrieved from the MushroomExpert.Com Web site: