Russula rosacea

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by Michael Kuo

Red Russula species are not typically very easy to identify, but this one has a hollowing red stem to go with its red cap, gills that eventually become cream-colored to pale yellow (as opposed to stark white), and an astoundingly acrid taste to boot. The red colors are quite beautiful, and do not fade when the mushrooms are dried.

Edibility is uncertain for this mushroom, but you're not likely to care after you taste it once!

Russula rosacea may have several forms or varieties--or there may be several closely related species involved; see the comments below.

Description:

Ecology: Mycorrhizal with hardwoods and conifers (especially pines); growing scattered or gregariously; summer and fall; probably widely distributed in North America.

Cap: 3-12 cm; convex when young, becoming broadly convex to flat to uplifted with a shallow depression; sticky when wet; smooth; dark to bright red but sometimes fading in age; the margin slightly lined; the cap "skin" easily peeling off from the margin to at least halfway to the center, and exposing rose-tinted flesh beneath.

Gills: Attached or running slightly down the stem; close or crowded; white to cream or yellowish in age.

Stem: 4-10 cm long; 1-2.5 cm thick; colored like the cap or paler--or flushed red over a white base color; brittle; dry; smooth; quickly becoming hollow; not bruising or staining; often eccentric, according to some authors.

Flesh: White; brittle.

Taste: Immediately very acrid; odor not distinctive.

Spore Print: Whitish to cream or yellowish (see comments below).

Chemical Reactions: In my collections, KOH is negative on the cap surface, erases the red colorations on the stem, and is slowly pale dirty yellowish on the flesh.

Microscopic Features: Spores 7-9 x 6-8 µ; with warts to 1.0 µ high; elliptical to nearly round.

REFERENCES: (Bulliard ex St. Amans) Fries, 1836. (Kauffman, 1918; Arora, 1986; Phillips, 1991/2005; Lincoff, 1992). Herb. Kuo 06269506, 08110201, 06150308.

Russula sanguinea may be a synonym, though there is some discussion in older texts as to whether the two mushrooms may be distinct--one with gills that run down the stem, and one with attached gills; or one with white spores and mature gills, and one with cream colored spores (though which name should be applied to which mushroom is not entirely clear). Michael Wood, at MykoWeb, says that "Russula sanguinea has been previously misidentified as Russula rosacea," but does not elaborate (link below). The Index Fungorum, which often has a bit of a European bias, claims that Russula rosacea and Russula sanguinea are both synonyms of Russula sanguinaria Rauschert 1989.

My own experience collecting this mushroom leads me to believe that its ecology includes being mycorrhizal with hardwoods--or that a variety or parallel species grows under hardwoods. I have also noticed variations in the color of the spore print, ranging from nearly white, to cream, to pale yellow. There may be a constellation of species meeting the description above.

Further Online Information:

Russula sanguinea at MykoWeb
Russula sanguinea at Roger's Mushrooms
Russula sanguinea at Fungi of Poland

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Cite this page as:

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