Amanita rubescens var. alba

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by Michael Kuo

This mushroom is a white, stocky variety of the well known "blushing" species, Amanita rubescens. It is found in eastern North America, often growing alongside the typical variety--but one does not find "intergrading" forms, which suggests that the two taxa are indeed distinct at some level. Western North America's Amanita novinupta is similar, but features a swollen stem base and patchlike, rather than warty, decoration on its cap.

Description:

Ecology: Mycorrhizal with conifers and hardwoods, but especially fond of oaks; early summer through fall; fairly widely distributed east of the Great Plains, but apparently absent south of (roughly) South Carolina.

Cap: 5-13 cm, convex to broadly convex or broadly bell-shaped, or nearly flat in age; dry or slightly sticky; with yellowish to creamy or grayish warts; surface white, developing pinkish or reddish shades; the margin not or only faintly lined.

Gills: Free from the stem or nearly so; white, discoloring reddish; close or crowded.

Stem: 5-14 cm long; up to 2 cm thick; with a swollen base; generally without prominent volval remnants (but perhaps with indistinct volval scales or zones); without a rim; white becoming stained pinkish to dirty red; smooth to finely hairy; with a white (rarely yellow or yellowish), fragile, skirtlike ring.

Flesh: White throughout, discoloring slowly pale pinkish red, especially around worm holes.

Spore Print: White.

Chemical Reactions: KOH on cap surface negative.

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

REFERENCES: Coker, 1917. (Saccardo XXVI [1972]; Tulloss, 2003; Tulloss, 2006.) Herb. Kuo 07070712.

Further Online Information:

Amanita rubescens var. alba at Tulloss's Studies in Amanita

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Cite this page as:

Kuo, M. (2008, March). Amanita rubescens var. alba. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita_rubescens_alba.html