What You Should Know
Russula xerampelina is a robust species with dark reddish-purple to brownish purple cap, cream-colored gills, a stipe flushed with pink or purple tones, a mild taste, and a distinctive shrimpy odor, especially in age.
The fruiting bodies appear in coniferous woodlands in autumn in northern Europe and North America. Their caps are colored various shades of wine-red, purple to green.
This edible mushroom is one of the most highly regarded brittle-gills for the table. It is also notable for the smelling of shellfish or crab when fresh.
Other names: Crab Brittlegill, Shrimp Mushroom, Woodland Russula, Herring Mushroom.
Russula xerampelina Mushroom Identification
Mycorrhizal with conifers or hardwoods; early summer through late fall in temperate regions, but also overwinter in warmer climates; widely distributed in North America.
4-30 cm; convex, becoming broadly convex, flat, or shallowly depressed; sticky when fresh (but a few species are dry-capped); fairly smooth or, in some species, almost velvety, especially when young; the margin usually not lined, or lined only faintly; colors ranging from reds and purples to browns and olives (but one species is yellow, and at least one is orangish), but often demonstrating considerable variability even within a single "species" or collection.
Attached to the stem or beginning to run down it, but often becoming separated from it with age; crowded, close, or nearly distant; white to creamy at first, but becoming creamy to yellowish or orangish-yellow by maturity; often bruising and discoloring yellowish-brown to brown.
3-12 cm long; 1-4 cm thick; more or less equal; dry; fairly smooth; white, or flushed with reddish to purplish shades; bruising slowly yellowish, then brown.
White; discoloring slowly yellowish brown to brownish or brown when sliced.
Odor and Taste
Odor fishlike or shrimplike, especially in age or when dried; taste mild.
Creamy, yellowish, or orangish-yellow.
Russula xerampelina Similar Species
Russulas are easy to recognize to genus by their brittle flesh, white- to cream-colored gills, and often, bright purple, red, or yellow caps. Unlike the related genus Lactarius, they do not ooze milky or colored juice (latex) where cut or broken. However, russulas are notoriously difficult to identify to species because their characters including their cap colors are strikingly variable. For the russulas, taste (hot or mild), spore print color (from white to yellow or ochre), and odor are useful characters helpful incorrect identification to species group, if not necessarily to an exact species.
Russula xerampelina is a species complex of several closely related species that are extremely hard to distinguish from each other. Russula xerampelina was originally described from Europe, and the Pacific northwest specimens may belong to a different species.
Russula Viridofusca is distributed across western North America and it is a similar species that share the shrimp- or fish-like odor. In R. viridofusca, unlike R. xerampelina, the cap margin is often ridged and tuberculate (ridges bear rows of minute bumps) and the cap is more likely to be yellow-brown or reddish-brown rather than red or purple.
All specimens with the characteristic wine-red purple cap, cream to yellow gills, cream-colored stem that slowly turns brown when handled, a mild taste, and an odor of fish or shrimp are considered edible for most people.
Russula xerampelina Medicinal Properties
Polysaccharides extracted from the mycelial culture of R. xerampelina and administered intraperitoneally into white mice at a dosage of 300 mg/kg inhibited the growth of Sarcoma 180 and Ehrlich solid cancers by 70% and 80%, respectively (Ohtsuka et al., 1973).
R. xerampelina extract was shown to be inhibitory to the growth of Plasmodium falciparum, a pyrimethamine-resistant malarial parasite (Lovy et al., 2000).
Russula xerampelina Taxonomy and Etymology
The Crab Brittlegill mushroom was first described scientifically in 1770 by the German botanist Jacob Christian Schaeffer, who gave it the binomial scientific name Agaricus xerampelina.
In 1838 the great Swedish mycologist Elias Magnus Fries transferred this species to the genus Russula, thus establishing its currently-accepted scientific name Russula xerampelina.
Synonyms of Russula xerampelina include Agaricus xerampelina Schaeff., Russula xerampelina var. xerampelina (Schaeff.) Fr., Russula alutacea var. erythropus Fr., Russula erythropus (Fr.) Pelt., Russula xerampelina var. erythropus (Fr.) Kühner Romagn., and Russula erythropus var. ochraceus J. Blum.
Russula, the generic name, means red or reddish, and indeed many of the brittlegills have red caps (but many more are not red, and several of those that are usually red can also occur in a range of other colors!). The specific epithet xerampelina comes from the Greek words xeros meaning dry, and ampělinos meaning 'of the vine' - indicating that this mushroom is the color of dried vine leaves.
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