Russula densifolia

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by Michael Kuo

Russula densifolia is part of the Russula nigricans species cluster. In its wide (and, I believe, its most appropriate) sense, the label Russula densifolia refers to those species with whitish to brown caps, close or crowded gills, and flesh that turns reddish, then slowly blackish on exposure. Russula nigricans, by contrast, has distant gills (and smaller spores). See the comments below, and the Key to Blushing Russulas for help distinguishing other species in the cluster.

Reports vary on the edibility of the species in the Russula nigricans cluster. At best, however, they are edible for some and inedible or even poisonous for others, causing gastric upset. Reports from those who have eaten the mushrooms in question are not stellar, anyway. All in all, the "blackening russulas" are not good candidates for culinary experiments.

Description:

Ecology: Mycorrhizal hardwoods or conifers; growing alone or scattered; summer and fall; widely distributed in North America.

Cap: 5-15 cm; broadly convex when young, later flat with a central depression, or shallowly vase-shaped; dry or slightly slimy at first or when wet; more or less smooth, or finely felty; initially whitish but soon discoloring to brownish, ashy gray, or blackish; often bruising reddish, then blackish when young (see third illustration); the margin initially somewhat inrolled, not lined or lined faintly and widely.

Gills: Attached or running very slightly down the stem; narrow; close or crowded; white to cream, eventually yellowish; bruising blackish, with a reddish phase first.

Stem: 1.5-9 cm long; 1-3.5 cm thick; whitish at first, soon darkening like the cap; bruising reddish, then blackish over the course of as much as half an hour; smooth.

Flesh: White; hard; bruising promptly or slowly reddish on exposure, then blackish over the course of as much as half an hour (see illustration).

Taste: Inconsistently recorded; mild or slowly slightly to very acrid. Odor not distinctive.

Spore Print: White.

Microscopic Features: Spores 7.5-10 x 6-8 µ; with warts to .5 µ high; with amyloid ridges forming a partial or complete reticulum; widely elliptical to nearly round.

REFERENCES: Secretan, 1833. (Kauffman, 1918; Shaffer, 1962; Arora, 1986; Phillips, 1991/2005.) Herb. Kuo 06289502, 09040202, 06150307, 08050302.

I am including Russula dissimulans in my concept of Russula densifolia; the former is a species authored by Robert Shaffer in the 1960's at the height of the hegemony of the microscope in mushroom identification, and differs only in the thickness of the cap skin. See the Key to Blushing Russulas for details.

Further Online Information:

Russula densifolia at MykoWeb
Russula densifolia at Roger's Mushrooms

Bruising progression, measured in minutes.

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Cite this page as:

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