Amanita russuloides

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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 Amanita gemmata--but the latter may be limited to western North America (my collections of it come from California and Colorado, while my Amanita russuloides collections come from Illinois and Kentucky). Additionally, the cap of Amanita russuloides turns pinkish orange in 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).

No amanita should be considered for the table!

Description:

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

Cap: 4-12 cm; convex to broadly convex, flat, or shallowly depressed in age; thin-fleshed; sticky when fresh but soon dry; pale dull yellow to straw yellow; with a few whitish to grayish warts that often disappear entirely; the margin grooved and pimply for 1-3 cm.

Gills: Free from the stem or nearly so; white to creamy; crowded.

Stem: 5-12 cm long; up to 2 cm thick; tapering slightly to the apex; whitish; smooth or finely hairy; whitish to yellowish; 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, fairly often, a collarlike rim.

Flesh: White; unchanging.

Spore Print: White.

Chemical Reactions: KOH on cap surface pinkish orange.

Microscopic Features: Spores 7.5-10 x 5-7 µ; smooth; broadly elliptical; inamyloid.

REFERENCES: Peck, 1873. (Saccardo, 1887; Murrill, 1913; Beardslee, 1914; Kauffman, 1918; Jenkins, 1977; Smith, Smith & Weber, 1979; Tulloss, 1995; Tulloss, 2003; McNeil, 2006.) Herb. Kuo 08010303, 08180602, 05290704.

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Cite this page as:

Kuo, M. (2008, March). Amanita russuloides. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita_russuloides.html