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Connopus acervatus

[ Basidiomycetes > Agaricales > Tricholomataceae > Connopus . . . ]

by Michael Kuo

Defining features for this distinctive mushroom, which was known as "Gymnopus acervatus" or "Collybia acervata" until very recently, include the densely clustered growth on the wood of conifers; the convex (not conical) reddish brown caps that fade to pinkish buff; and the reddish to reddish brown stem that is bald except for the slightly fuzzy base. Older specimens demonstrate a marked contrast between the pale caps and the reddish stems.

A recent study by Hughes and collaborators (2010) used two genes (ITS and LSU) to examine many collybioid mushrooms; collections of "Gymnopus acervatus" grouped separately from other species of Gymnopus and from species of Rhodocollybia. Thus, the authors proposed a new genus name, Connopus, to accommodate Gymnopus acervatus. The authors' data found potential support for the idea that the western North American version of Connopus acervatus "might be a distinct species" (p. 1476).


Ecology: Saprobic; growing in dense clusters on conifer stumps (and sometimes from buried conifer wood, appearing terrestrial); summer and fall, or in winter in Texas and California; fairly widely distributed in North America but apparently absent or rare in southwestern and southeastern areas.

Cap: 1-5 cm; convex, becoming planoconvex; smooth; reddish brown and moist when young and fresh, but soon fading to brownish or pinkish buff (often passing through a two-toned stage).

Gills: Attached to the stem broadly or narrowly; close or crowded; whitish when young, developing pink tones.

Stem: 2-12 cm long; up to about 6 mm thick; more or less equal; dry; hollow; smooth except for whitish fuzz near the base; reddish brown to purplish brown; not fading as quickly as the cap.

Flesh: Thin; whitish.

Odor and Taste: Odor not distinctive; taste mild or bitter.

Spore Print: White.

Microscopic Features: Spores: 5.5-7 x 2.5-3 µ; smooth; elliptical or nearly cylindric; inamyloid. Pleurocystidia absent. Cheilocystidia up to about 40 µ long; variously shaped; often with protrusions or lobes--or, in western North American collections, more or less cylindric with subclavate or merely rounded apices. Pileipellis a tangle of cylindric, branching (but not diverticulate or coralloid) hyphae 2-5 µ wide.

Collybia acervata and Gymnopus acervatus are synonyms.

REFERENCES: (Fries, 1821) K. W. Hughes, Mather & R. H. Petersen, 2010. (Saccardo, 1887; Kauffman, 1918; Smith, Smith & Weber, 1979; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992; Barron, 1999; Halling, 2004; McNeil, 2006; Miller & Miller, 2006; Trudell & Ammirati, 2009; Hughes et al., 2010.) Herb. DBG 18199.

Further Online Information:

Gymnopus acervatus at Roy Halling's Collybia site
Gymnopus acervatus at MykoWeb
Collybia acervata at Roger's Mushrooms


Connopus acervatus

Connopus acervatus

Connopus acervatus

Connopus acervatus

Connopus acervatus

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Cite this page as:

Kuo, M. (2013, January). Connopus acervatus. Retrieved from the MushroomExpert.Com Web site: