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Tricholoma caligatum

[ Basidiomycetes > Agaricales > Tricholomataceae > Tricholoma . . . ]

by Michael Kuo

Finally, after years of searching, I had found the prized "American Matsutake," Tricholoma magnivelare. I was on my hands and knees in eastern Kentucky's Daniel Boone National Forest, eagerly taking pictures of what I was sure would be delicious mushrooms. Writing notes, I was a little surprised that the mushrooms lacked a distinctive odor, since Tricholoma magnivelare is almost always described as having a fragrant, spicy smell. Then I tasted them. The hills of Kentucky have heard such expletives before, I'm sure, but perhaps not for the same reasons.

Here I will simply say that the taste of Tricholoma caligatum is bitter, strong, and disgusting. Its ring and general stature are indeed like Tricholoma magnivelare, but it is not at all pleasant to taste. Additionally, the brown scales and fibers on Tricholoma caligatum tend to be darker and more prominent. The way I am treating it, Tricholoma caligatum is mycorrhizal with hardwoods--as opposed to the conifer-loving Tricholoma magnivelare--and has a bitter taste, at least most of the time. It may be the case that mild-tasting collections of Tricholoma caligatum have been made, but this possibility can't be reliably determined, given the enormous confusion surrounding the naming of species in the caligatum-magnivelare complex (see the comments below).


Ecology: Mycorrhizal with hardwoods, especially oaks; growing scattered or gregariously, sometimes in clusters; probably widely distributed in North America, and extending at least as far south as Costa Rica; late summer and fall.

Cap: 4-12 cm; broadly convex or nearly flat; dry; white, overlaid with prominent tan to dark brown fibers and scales.

Gills: Attached to the stem; close; white, developing brown stains and spots with age.

Stem: 4-9 cm long; 1-3 cm thick; more or less equal; white above the ring, covered with brown fibers and scales below; dry; partial veil white and Kleenex-like, collapsing to form a prominent ring with a white upper edge and a brownish lower edge.

Flesh: White; not changing on exposure.

Odor and Taste: Taste bitter (or possibly mild; see the comments below); odor not distinctive.

Spore Print: White.

Microscopic Features: Spores 5-8 x 4.5-5 µ; smooth; elliptical; inamyloid. Cystidia absent. Clamp connections absent.

REFERENCES: (Viviani, 1834) Ricken, 1915. (Kauffman, 1918; Thiers & Sundberg, 1976; Smith, Smith & Weber, 1979; Smith, 1979; Ovrebo, 1980; Phillips, 1991/2005; Shanks, 1994; Roody, 2003.) Herb. Kuo 10010407, 07250605.

Armillaria caligata is a former name.

The mess surrounding the taxonomic status of Tricholoma caligatum cannot be cleaned up, in my opinion, until someone puts the many questions to rest with DNA sequencing. Various attempts have been made to delineate species and varieties on the basis of subtle differences in taste, odor, reactions to iron salts, and the presence or absence of bluish gray stains on the gills. If you are interested in this quagmire, see Smith's 1949 "The stirps Caligata of Armillaria in North America" (Sydowia 8: 368-377) and Kytovuori's 1989 "The Tricholoma caligatum group in Europe and North Africa" (Karstenia 28: 65-77). Or, if you are willing to trust me, you can take my word that you will come away from these reading experiences less sure of things, rather than more--especially when the writings of other Tricholoma experts (Ovrebo, 1973 & 1980; Shanks, 1994 & 1997) are factored in. And if DNA study of the Tricholoma caligatum complex parallels what has been discovered so far with the Matsutake complex (for example, that the Swedish "Tricholoma nauseosum" is identical to the Japanese Tricholoma matsutake), these distinctions are likely to collapse.

A California version of Tricholoma caligatum (sensu Shanks, 1994) grows under conifers from "November to December in northern coastal forests and low elevation montane forests of the Sierra Nevada"; it is extremely bitter. Given its widely different mycorrhizal associations, it may well be a distinct species. I have collected a mild-tasting form of Tricholoma caligatum under spruce and fir in the Rocky Mountains.

Further Online Information:

Armillaria caligata at Roger's Mushrooms
Tricholoma caligatum at Macrofungi of Costa Rica


Tricholoma caligatum

Tricholoma caligatum

Tricholoma caligatum

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Kuo, M. (2004, December). Tricholoma caligatum. Retrieved from the MushroomExpert.Com Web site: