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Tricholoma focale

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

by Michael Kuo

Found under conifers throughout northern and montane North America, Tricholoma focale is fairly easily identified on the basis of its orange brown colors, its collapsing cottony ring, and its mealy odor. With maturity, olive shades often begin to develop on the cap--reminiscent of the orange-to-olive developments in Omphalotus olivascens.

Armillaria zelleri is a former name, and is still used in many field guides; see the discussion below for details on the synonymy.


Ecology: Mycorrhizal with conifers--especially spruces and pines; growing alone, scattered, or gregariously; fall (also over winter in warm climates); fairly widely distributed in northern and montane North America.

Cap: 2.5-13.5 cm; convex, becoming broadly convex to nearly flat when mature; sticky at first, but soon dry; covered with long fibrils; brown to yellow brown or, more commonly, orange-brown; often developing olive hues; the margin at first inrolled.

Gills: Usually attached to the stem by a notch; close or crowded; whitish; often discoloring and spotting brown.

Stem: 4.5-15 cm long; 1-3 cm thick; more or less equal, or swollen toward the base; with a cottony white ring that discolors brownish and often collapses with age; smooth above the ring, but shaggy below it, with brown fibrils over a buff ground color.

Flesh: Whitish or slightly brownish in places.

Odor and Taste: Odor mealy; taste mealy, often with a foul or bitter component.

Spore Print: White.

Microscopic Features: Spores 4.5-6.5 x 3-4 µ; smooth; elliptical; inamyloid. Pleurocystidia and cheilocystidia absent. Pileipellis a cutis of cylindric elements 2-7 µ wide, embedded in a gelatinous matrix; hyaline to brown or orangish brown in KOH. Clamp connections absent.

REFERENCES: (Fries, 1838) Ricken, 1914. (Saccardo, 1887; Kauffman, 1918; Smith, 1949; Ovrebo, 1973; Ovrebo & Tyluki, 1975; Thiers & Sundberg, 1976; Smith, Smith & Weber, 1979; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Shanks, 1994; Evenson, 1997; Barron, 1999; McNeil, 2006; Miller & Miller, 2006.)

Armillaria focalis is a synonym. Armillaria zelleri and Tricholoma zelleri are synonyms, according to most mycologists. Armillaria zelleri was named by Stuntz and Smith (in Smith, 1949), who argued that its sticky cap distinguished it from Armillaria focalis. However, while the original description (Fries, 1838) of Armillaria focalis did not mention whether the cap was sticky or dry, contemporary European concepts of the species (now known as Tricholoma focale) require a sticky cap--which removes the stated justification for Armillaria zelleri as a distinct species. Several North American authors (Ovrebo, 1980; Shanks, 1994, 1997) have reduced Armillaria zelleri to synonymy with Tricholoma focale, but have done so in officially unsanctioned publications (doctoral dissertations and the Agaricales of California series), so the name Tricholoma zelleri is still, strictly speaking, officially valid (Armillaria zelleri was reduced to synonymy with Tricholoma zelleri by Ovrebo & Tyluki, 1975).

Further Online Information:

Armillaria zelleri at Roger's Mushrooms


Tricholoma focale

Tricholoma focale

Tricholoma focale

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Kuo, M. (2008, December). Tricholoma focale. Retrieved from the MushroomExpert.Com Web site: