Russula crustosa

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

by Michael Kuo

Russula crustosa is a confusing species, treated in various (and differing) ways in field guides and technical literature. Only a few species of Russula have cracked-up, "quilted" cap surfaces, and Russula virescens is the most well-known of these species. It is distinguished from Russula crustosa on the basis of its greener cap colors and its less abundant cystidia. Russula crustosa is typically brownish to yellowish (sometimes with orangish colorations added in), and has abundant cystidia. Some authors stress a difference in spore print color (white for Russula virescens; creamy or buff for Russula crustosa), but my experience in Russula and Lactarius suggests that subtle differences in spore print color may not be as informative as is often supposed.

In short, I would not suggest betting the house on an identification of either species, and I wouldn't be surprised if a thorough study of the "quilted russulas" (perhaps a study involving DNA analysis) were to reveal more species than we currently recognize--or the opposite: that there is only one species involved, variable in its colors and cystidia.

As far as anyone knows, all of the quilted russulas are edible.

Description:

Ecology: Mycorrhizal with hardwoods, especially oaks; growing alone or gregariously; summer; widely distributed east of the Rocky Mountains.

Cap: 5-10 cm; round to convex when young, becoming broadly convex to flat to uplifted with a shallow depression; dry; soon cracking up into patches; brownish, buff, yellowish brown or greenish, with lighter shades (including pale orange) mixed in; margin not lined to very slightly lined; cap "skin" peeling about half-way to the center.

Gills: Attached to the stem; close or crowded; some forking; white to cream.

Stem: 3.5-9 cm long; 1.5-3 cm thick; white; dry; smooth.

Flesh: White; brittle; thick.

Taste: Mild; odor not distinctive.

Spore Print: Pale buff (officially; I would add "white" as a possibility).

Microscopic Features: Spores 6-9 x 5.5-7 µ; elliptical to nearly round; with warts to 0.5 µ high; without amyloid connecting lines.

REFERENCES: Peck. (Kibby & Fatto, 1990; Phillips, 1991/2005.) Herb. Kuo 06220401.

The mushroom treated as Russula crustosa by Lincoff (1992) is probably Russula virescens.

Further Online Information:

Russula crustosa at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2005, January). Russula crustosa. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/russula_crustosa.html