Cortinarius cotoneus

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by Michael Kuo

The North American version of the European species Cortinarius cotoneus could be nicknamed the "Black-Eyed Cort," since it features a distinctive black center when mature. The cap is dry, yellowish brown, and finely hairy or scaly. The young gills are yellowish, and the young stem is sheathed with yellowish universal veil material. Like other species of Cortinarius it features a cortina and a rusty brown spore print.

"Cortinarius cotoneus" is undoubtedly a cluster of closely related species. Differences in physical features, traditionally the basis for separation of species, abound in this area of the genus. The original Scandinavian Cortinarius cotoneus, to judge from photos and descriptions in field guides, does not feature such a strikingly contrasting black center (see Irene Andersson's photo to the right). Cortinarius clandestinus is nearly identical, but has gills that are whitish before maturity. And while I am usually not a fan of "splitting" on the basis of subtle differences in physical features, there are ecological factors separating some of these mushrooms. The European Cortinarius cotoneus is mycorrhizal with hardwoods, for example, while most North American versions are mycorrhizal with conifers. A California version is mycorrhizal with tanoak.

While the edibility of Cortinarius cotoneus is not known, it is potentially deadly poisonous, since it belongs to subgenus Leprocybe of Cortinarius.

Description:

Ecology: Mycorrhizal with conifers (and with Tanoak in California); growing alone, scattered, or gregariously; summer and fall, or in winter in California; possibly widely distributed (as a species cluster) in North America.

Cap: 3-10 cm; convex, conical, or bell-shaped at first, becoming broadly convex, flat, or broadly bell-shaped; dry; finely hairy or scaly, especially over the center; yellowish brown to olive brown overall, with a dark brown to black center.

Gills: Attached to the stem; close; yellowish to olive yellow at first, becoming cinnamon to rusty; covered by a cortina when young.

Stem: 4-15 cm long; up to 2 cm thick at the apex; more or less equal, or enlarged downward; dry; finely silky; pale yellowish or pale olive above; sheathed with yellowish universal veil material below when young, later becoming brownish; sometimes with a rusty ring zone, or even a rudimentary ring resulting from the folded back edge of the universal veil material.

Flesh: Yellowish to pale brownish.

Odor: Radishlike.

Chemical Reactions: KOH on cap surface dark red to black.

Spore Print: Rusty brown.

Microscopic Features: Spores 7-9 x 5-7 µ; elliptical or nearly round; roughened.

REFERENCES: Fries, 1838. (Lincoff, 1981; Arora, 1986; Phillips, 1991/2005; Hansen & Knudsen, 1992.) Herb. Kuo 09120404.

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Cite this page as:

Kuo, M. (2005, January). Cortinarius cotoneus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/cortinarius_cotoneus.html