Major Groups > Gilled Mushrooms > Pale-Spored > Russula > Blushing & Blackening Russulas > Russula species 02 |
[ Basidiomycota > Russulales > Russulaceae > Russula . . . ] Russula species 02 by Michael Kuo, 29 October 2024 This is an apparently unnamed Rocky Mountain version of the European species Russula albonigra. Like the European species, it features white-when-young surfaces that bruise and stain black, without an intermediate red-staining stage. The Rocky Mountain species described here is a conifer-associated mushroom with a cap that develops brown colors as it matures, along with an indistinct taste and spores with ornamentation so low that it is hard to discern with light microscopy. Russula atrata, described from the mountains of Oregon (Shaffer 1962), is similar but does not turn brown. There may well be further western North American versions of "Russula albonigra"; DNA-informed study of many well-documented collections is needed. In Europe, a recent study of albonigra-like collections (de Lange et al. 2021) uncovered several European cryptic species. In eastern North America, Russula michiganensis is similar, but does not develop brown colors, and appears under oaks. Thanks to the Denver Botanic Garden for facilitating study of one of the collections described here, and thanks to Ikuko and Ed Lubow for documenting the collection. Description: Ecology: Mycorrhizal with conifers (collected under Engelmann spruce, subalpine fir, and lodgepole pine) at high elevation; growing gregariously; July and August; distribution uncertain. The illustrated and described collections are from Colorado. Cap: 5–9 cm at maturity; broadly convex or nearly flat; bald; sticky when young but soon dry; white when fresh and young, but soon discoloring dark brown; bruising black; the margin not lined. Gills: Attached to the stem; close; short-gills present; creamy white; bruising and staining black. Stem: 3–6 cm long; 1–2.5 cm thick; more or less equal; dry; bald; white when fresh, but soon bruising dark gray to black. Flesh: White; staining dark gray to black when sliced. Odor and Taste: Not distinctive. Microscopic Features: Spores 9–12 x 6–8 µm; broadly ellipsoid; ornamentation as isolated amyloid warts under 0.2 µm high (virtually imperceptible), without connecting lines, not forming reticula. Basidia 50–60 x 6–7 µm; subclavate; 4-sterigmate. Macrocystidia 70–90 x 5–7.5 µm; fusiform; smooth; thin-walled; hyaline in KOH. Pileipellis an ixocutis of elements 2–4 µm wide, smooth, brown in KOH; pileocystidia not found. REFERENCES: (Shaffer, 1962; Adamčík & Buyck, 2014; de Lange et al., 2021.) Herb. DBG F-029408. This site contains no information about the edibility or toxicity of mushrooms. |
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Cite this page as: Kuo, M. (2024, October). Russula species 02. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/russula_species_02.html |