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The Genus Catathelasma  

[ Basidiomycetes > Agaricales > Tricholomataceae . . . ]

by Michael Kuo

Catathelasma is fairly easily recognized, as a genus, by a combination of features:

  • Terrestrial growth under conifers.
  • Large size and tough consistency.
  • Gills running down the stem.
  • Stem tapered and rooting (often buried).
  • Ring prominent and double.
  • Spores amyloid, elongated.

"Large" often means very large, with caps in the 20-40 cm range, and if you have found specimens this size, very few mushrooms could be easily mistaken for a Catathelasma. However, caps in the 10-20 cm range are also common, and when this is the case a few contenders for your identification attention enter the picture: the Tricholoma caligatum species group (gills not running down the stem; sometimes under hardwoods; ring not double; spores inamyloid); the Tricholoma murrillianum species group (like Tricholoma caligatum but whiter and with a distinctive, spicy odor); and, perhaps, a few species of Floccularia (ring sheathlike, not double; gills not running down the stem; spores amyloid but not elongated).


Catathelasma ventricosum

Catathelasma imperiale

Catathelasma imperiale

About five species of Catathelasma have been described from North America. One of these, Catathelasma singeri, is a slimy, dull yellow mushroom found once near Aspen, Colorado, by Alexander Smith and other mycologists, who write: "All those who saw the fresh specimen supposed it to be an Hygrophorus. It was only when studied in the laboratory back in Ann Arbor that the significance of the specimen and its generic identity became apparent" (Mitchel & Smith, 1978; p. 1055). Other species include the imperfectly known Catathelasma evanescens (from Wyoming, with nearly distant gills and a volva-like veil) and Catathelasma macrosporum (also from the Rocky Mountains, with spores described at the turn of the 20th century as slightly wider than the spores of other species). The two "main" species, however, are keyed out below.

Key to 2 Species of Catathelasma in North America

1.Primarily northeastern in distribution but also recorded in the Pacific Northwest; cap white or whitish, dry; taste mild or disagreeable, but not usually mealy; basidia under 45 µ long.

1.Primarily western in distribution; cap brownish, sticky when young; taste mealy; basidia up to 75 µ long.


Mitchel, D. H. & Smith, A. H. (1978). Notes on Colorado fungi III: New and interesting mushrooms from the aspen zone. Mycologia 70: 1040-1063.

Singer, R. (1978). Keys for the identification of the species of Agaricales II. Catathelasma. Sydowia 31: 193-194.

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Cite this page as:

Kuo, M. (2006, October). The genus Tricholoma. Retrieved from the MushroomExpert.Com Web site:

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