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Tricholoma squarrulosum

[ Basidiomycota > Agaricales > Tricholomataceae > Tricholoma . . . ]

by Michael Kuo

One of many gray species in the genus, Tricholoma squarrulosum may be able to Tricholoma, but lomas are not very observant and they get bored easily. You, on the other hand, will not be tricked, since you will notice the fibers and scales on the cap and the stem—as well as the mealy odor and taste, the often-grayish gills, and the growth under hardwoods in the Great Lakes region.

Tricholoma michiganense and Tricholoma atrosquamosum var. squarrulosum are synonyms.

Thanks to Charlotte Lukes for collecting, documenting, and preserving Tricholoma squarrulosum for study; her collection is deposited in The Herbarium of Michael Kuo.


Ecology: Mycorrhizal with various hardwoods; growing alone, scattered, or gregariously; fall; widely distributed east of the Great Plains, but more common in the Great Lakes region than elsewhere. (Reports from the West Coast represent probable misidentifications). The illustrated and described collections are from Michigan and Wisconsin.

Cap: 2.5–8 cm; convex, becoming broadly convex to nearly flat when mature; dry; grayish underneath a dense covering of dark gray to nearly black fibers and scales; the margin inrolled and hairy, especially when young.

Gills: Attached to the stem by a notch; close or nearly crowded; short-gills frequent; whitish to dull gray.

Stem: 3–6 cm long; 0.5–2 cm thick; more or less equal above a swollen base; dry; with gray to nearly black fibrils and scales over a grayish to whitish ground color; sometimes staining red near the base; basal mycelium white.

Flesh: Whitish to grayish, or somewhat brownish in the stem; not changing on exposure—or, in the stem base, turning slowly pinkish red (and retaining the red color after drying for the herbarium).

Odor and Taste: Mealy.

Chemical Reactions: KOH negative on cap surface.

Spore Print: White.

Microscopic Features: Spores 5–7 x 3–4 µm; ellipsoid, with a small apiculus; smooth; hyaline in KOH; inamyloid. Basidia 4-sterigmate. Pleurocystidia, cheilocystidia not found. Pileipellis a cutis of cylindric elements 5–15 µm; wide, smooth, septate, hyaline to brownish; interspersed with upright aggregations of dark brown elements (the squamules). Clamp connections not found.

REFERENCES: Bresadola, 1892. (Saccardo, 1902; Smith, Smith & Weber, 1979; Ovrebo, 1980; Shanks, 1994; McNeil, 2006; Bessette et al., 2013; Christensen & Heilmann-Clausen, 2013; Kuo & Methven, 2014.) Herb. Kuo 09120502, 10061801.

This site contains no information about the edibility or toxicity of mushrooms.


Tricholoma squarrulosum

Tricholoma squarrulosum

Tricholoma squarrulosum

Tricholoma squarrulosum
Dried specimen: interior of stem base

Tricholoma squarrulosum

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Kuo, M. (2018, November). Tricholoma squarrulosum. Retrieved from the MushroomExpert.Com Web site: