Russula ochroleucoides

[ Basidiomycetes > Russulales > Russulaceae > Russula . . . ]

by Michael Kuo

This beautiful yellow Russula was originally described by Kauffman, in 1918, on the basis of his Michigan collections. Its range has since been expanded to include most of eastern North America. The fact that its flesh does not turn gray when sliced separates it from Russula claroflava, and the fact that its stem is white or at most pale yellowish separates it from the yellow-stemmed Russula flavida.

However, Russula ochroleucoides is very hard to distinguish from several other species (including Russula lutea and Russula aurantiolutea) and one is ultimately forced to resort to microscopic features and such dubious characters as the fact that the "skin" does not peel away easily from the cap. See the page for the genus Russula for a detailed look at what I went through to identify the illustrated mushrooms.

Russula ochroleucoides is apparently edible, but it is hard to identify with certainty and in many collections it has an unpalatable, acrid taste. I do not recommend eating it.

Description:

Ecology: Mycorrhizal with hardwoods, especially oaks and beech; growing alone or gregariously; summer and fall; eastern and northeastern North America.

Cap: 6-12 cm; convex, becoming broadly convex to flat, or with a shallow depression; dry (the illustrated collection was made immediately after a rain, causing the mushrooms to appear slimy, but microscopic analysis did not reveal gelatinized cells on the cap surface, indicating the mushrooms were not truly "viscid"); smooth or finely dusted; yellow; the margin vaguely lined or not; the skin not peeling away easily from the margin.

Gills: Attached to the stem; close; whitish, sometimes developing brownish spots and discolorations.

Stem: 4-6 cm long; 1.5-2 cm thick; more or less equal; hollowing somewhat with maturity; sometimes finely dusted or hairy; white, sometimes pale yellowish near the base; occasionally discoloring brownish in places.

Flesh: Whitish; unchanging on exposure.

Taste: Mild or somewhat bitter or acrid; odor faintly fragrant.

Spore Print: White or creamy yellowish.

Chemical Reactions: KOH on cap surface negative; iron salts negative on stem surface.

Microscopic Features: Spores 7-10 x 5.5-8 µ; broadly elliptical; with warts projecting 1 µ or less; with connecting lines that usually form partial or nearly complete reticula. Encrusted primordial hyphae not present in cuticle.

REFERENCES: Kauffman, 1918. (Kauffman, 1918; Kibby & Fatto, 1990; Phillips, 1991/2005; Roody, 2003.) Herb. Kuo 07250402.

"Russula ochraleucoides" (with an "a") is a misspelling originally made by Kauffman; later mycologists corrected his Latin.

Further Online Information:

Russula ochroleucoides at Roger's Mushrooms

© MushroomExpert.Com