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Amanita russuloides

[ Basidiomycetes > Agaricales > Amanitaceae > Amanita . . . ]

by Michael Kuo

North American mycological pioneer Charles Peck thought this mushroom looked like a russula--presumably, something like Russula pectinatoides, with a strongly "tuberculate-striate" (simultaneously lined and pimply) cap margin. In this sense Amanita russuloides is definitely russula-like, especially when viewed from the top.

Amanita russuloides appears east of the Great Plains, and features a dull yellow to straw colored cap, scattered grayish to whitish warts, a fragile ring that often disappears, and a small basal bulb that often features a collarlike rim. Not a lot separates Amanita russuloides from the North American version of Amanita gemmata--but the latter is apparently limited to western North America. Additionally, the cap of Amanita russuloides turns pinkish orange with KOH while the cap of Amanita gemmata displays a negative reaction; the spores of Amanita russuloides are slightly smaller; Amanita russuloides is, on average, less stocky; and the cap margin of Amanita russuloides is substantially more striate.

Amanita russuloides should also be compared with Amanita multisquamosa (cap whitish with a yellowish center, warts more numerous, margin less prominently lined).

Description:

Ecology: Mycorrhizal with conifers and hardwoods, but especially fond of oaks; often found in grassy areas; growing alone, scattered, or gregariously; summer and fall; possibly widely distributed east of the Great Plains.

Cap: 3-9 cm; convex to broadly convex, flat, or shallowly depressed in age; thin-fleshed; sticky when fresh but soon dry; brownish yellow when very young, becoming pale yellow to straw yellow or, in old age, nearly whitish; with a few whitish to grayish warts that often disappear entirely; bald; the margin lined and pimply for 1-3 cm.

Gills: Free from the stem or nearly so; white to creamy; crowded or close; short-gills occasional.

Stem: 4-9 cm long; 0.5-1.5 cm thick; tapering slightly to the apex; whitish; bald or finely hairy; whitish, discoloring brownish; with a fragile whitish ring that can appear fairly high on the stem or nearly at the bottom and often disappears entirely; terminating in a small basal bulb; with fragile white volval remnants that form a few vague rings or, more often, a collarlike rim.

Flesh: White; unchanging.

Odor: Not distinctive.

Chemical Reactions: KOH on cap surface orange to pinkish orange.

Spore Print: White.

Microscopic Features: Spores 8-10.5 x 5.5-8 µ; smooth; broadly elliptical; inamyloid. Basidia 4-spored; without clamps. Pileipellis an ixocutis of elements 2.5-8 µ wide. Lamellar trama bilateral; subhymenium cellular.


REFERENCES: (Peck, 1873) Saccardo, 1887. (Murrill, 1913; Beardslee, 1914; Kauffman, 1918; Smith, Smith & Weber, 1979; McNeil, 2006.) Herb. Kuo 08010303, 08180602, 05290704, 06280804, 06041304.


This site contains no information about the edibility or toxicity of mushrooms.


 

Amanita russuloides

Amanita russuloides

Amanita russuloides

Amanita russuloides

Amanita russuloides
KOH

Amanita russuloides
Spores



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Kuo, M. (2013, April). Amanita russuloides. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita_russuloides.html