Russula paludosa sensu Shaffer (1970)

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by Michael Kuo

Russula buffs who have clicked to this page expecting to see a red mushroom will probably not be pleased with me for putting the name Russula paludosa on the mushrooms illustrated in the top photo. Not only are they pale orangish rather than red, but the flesh stains ashy gray on exposure--something that is not supposed to happen with Russula paludosa as it is usually described.

However, the fine print of most descriptions of Russula paludosa acknowledges the potential for orangish or yellowish caps--and Irene Andersson's photo of the species in Sweden, to the right, demonstrates the orangish-to-reddish variability in a single collection. As for the gray staining, Russula expert Robert Shaffer (1970) describes the North American version of this European species as potentially "cinerescent" (turning gray) in the flesh and on the stem surface. Shaffer cites northern Michigan as the location for his graying collections, not far from where I made the illustrated collection.

Thus, while Russula paludosa is not typically a very distinctive species, blending in with any number of red russulas, the gray staining form is unusual and fairly easy to identify (providing you have Shaffer's description on hand)--though microscopic characters should be verified before betting the house on your identification.

Russula paludosa should probably not be eaten. While several field guides label it "edible," it is very hard to identify with certainty, especially when it is red (which is most of the time). At least one red russula is known to be poisonous.

Description:

Ecology: Mycorrhizal with conifers; often found in sphagnum in conifer bogs; growing alone or gregariously; summer and fall; eastern and northeastern North America.

Cap: 6-15 cm; convex, becoming broadly convex to flat with a shallow depression; slimy when wet and fresh, but soon dry; smooth; usually red to reddish brown, but sometimes orangish or yellow; the margin often lined for 2-8 mm at maturity; the skin peeling away easily from the margin, sometimes beyond halfway to the center.

Gills: Attached to the stem; close; often forked near the stem; whitish becoming pale yellowish.

Stem: 4.5-12 cm long; 1.5-4.5 cm thick; more or less equal; hollowing with maturity; sometimes finely dusted or hairy near the apex or base; white, sometimes with a pale pinkish flush; sometimes bruising slowly grayish.

Flesh: Whitish; unchanging on exposure or changing slowly to grayish.

Taste: Mild or somewhat acrid; odor not distinctive.

Spore Print: Pale orange yellow.

Chemical Reactions: KOH on cap surface negative; iron salts pinkish to pinkish gray on flesh and stem surface.

Microscopic Features: Spores 7.5-11 x 7-9 µ; broadly elliptical; with warts projecting about 1 µ; connecting lines variable (sometimes isolated and few; sometimes frequent and forming partial reticula).

REFERENCES: Britzelmayr, 1891. (Shaffer, 1970; Kibby & Fatto, 1990; Phillips, 1991/2005; Hansen & Knudsen, 1992; Barron, 1999.) Herb. Kuo 09120410.

Further Online Information:

Russula paludosa at Roger's Mushrooms
Russula paludosa at Fungi of Poland

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