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Cortinarius olearioides

[Basidiomycetes > Agaricales > Cortinariaceae > Cortinarius ... ]

by Michael Kuo

Associated with hardwoods in eastern North America, this species of Cortinarius is a gorgeous shade of bright yellow when fresh and young. No, the mushrooms in the photos are not a gorgeous shade of bright yellow. I seem to have a problem when it comes to the charismatic species of Cortinarius, and I always seem to find them past their prime (see the page for Cortinarius violaceus for an even more painful example). As is the case for all the yellow to orange or brownish Cortinarius species with basal bulbs, the color of the young gills (yellow) and the morphology of the spores (see below) are crucial for identification of Cortinarius olearioides.

Cortinarius subfulgens is a synonym. I suspect that both "Cortinarius fulgens" and Cortinarius fulmineus var. sulphureus as described by Kauffman (1918, 1932) on the basis of Michigan material represent Cortinarius olearioides as I am treating it here . . . and it is possible that other field guide treatments of Cortinarius fulgens and Cortinarius fulmineus also represent, at least in part, Cortinarius olearioides.


Ecology: Mycorrhizal with hardwoods--especially oaks and beech; growing scattered or gregariously; fall; eastern North America from at least Illinois to Québec.

Cap: 5-15 cm; convex, becoming broadly convex or nearly flat; sticky when fresh; silky to bald; bright yellow when fresh and young, maturing to orange-brown or yellowish brown.

Gills: Attached to the stem; close; bright yellow at first, becoming orangish rusty brown.

Stem: 4-10 cm long; up to about 3 cm thick above; more or less equal above a swollen, rimmed basal bulb; pale to bright yellow, discoloring brownish; dry; bald or slightly hairy in places; often with rusty fibrils or a ring zone.

Flesh: Pale yellow to whitish.

Odor and Taste: Odor not distinctive, or fruity, or potato-like. Taste not distinctive.

Chemical Reactions: KOH red on cap surface; reddish on flesh.

Spore Print: Rusty brown.

Microscopic Features: Spores 9-12 x 5-6.5 µ; limoniform; coarsely and moderately to strongly verrucose. Pleuro- and cheilocystidia absent. Pileipellis an ixocutis of clamped elements.

REFERENCES: Rob. Henry, 1987. (Kauffman, 1918 [fulgens, fulmineus]; Kauffman, 1932 [fulgens, fulmineus]; Moser, 1983; McNeil, 2006 [fulgens]; Knudsen & Vesterholt, 2008.) Herb. Kuo 09260804.

This site contains no information about the edibility or toxicity of mushrooms.


Cortinarius olearioides

Cortinarius olearioides

Cortinarius olearioides

Cortinarius olearioides

Cortinarius olearioides

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Kuo, M. (2011, December). Cortinarius olearioides. Retrieved from the MushroomExpert.Com Web site: