Amanita brunnescens

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by Michael Kuo

Sometimes called the "Cleft-Foot Amanita," Amanita brunnescens is an eastern species with a brown to whitish cap. The distinguishing feature of this relatively easily recognized mushroom is its stem, which, when acting the way it's supposed to, ends in an abrupt basal bulb that is split or "chiseled" in one or more places, and discolors reddish brown. See the fourth illustration for an example of a "classic" Amanita brunnescens stem. Unfortunately for would-be Amanita identifiers, Amanita brunnescens doesn't always fit its mold; see the stem bases in some of the other illustrations. But while the base of the stem may not always be bulbous and split, the reddish brown discolorations are usually consistent.

The other Amanita species that stain reddish, Amanita rubescens and Amanita flavorubescens, are easily separated; their discolorations are more pinkish and reddish (not really reddish brown), and their stems never end in split basal bulbs.

Do not eat this or any other Amanita!

Description:

Ecology: Mycorrhizal with hardwoods and conifers--"often in stands of pole-sized saplings," according to Smith (1979); summer and fall; east of the Rocky Mountains, and in eastern Texas.

Cap: 4-15 cm, convex, becoming broadly convex with a central bump, flat, or even shallowly depressed in age; sticky at first or when wet; deep brown to mottled brown and white to nearly whitish overall (see comments below), often with a darker center; sometimes streaked in appearance; usually with a few scattered white to grayish or tan warts; margin even or faintly lined.

Gills: Free from the stem; white; close or crowded; sometimes discoloring brownish or reddish brown.

Stem: 5-15 cm long; 1-2 cm thick; tapering to apex; smooth; with a relatively persistent ring that sometimes collapses against the stem; usually ending in an abrupt basal bulb that is typically "chiseled" or split vertically in one or more places; discoloring and bruising reddish brown, especially near the base.

Flesh: White throughout; firm; sometimes discoloring or bruising reddish brown.

Chemical Reactions: KOH on cap surface negative; yellowish on flesh in stem base.

Spore Print: White.

Microscopic Features: Spores 7-10 x 7-10 µ; smooth; round or nearly so; amyloid.

Amanita brunnescens var. pallida, recognized by some authors, is virtually identical, but has a nearly white cap.

A variety of Amanita citrina has a similarly chiseled or split basal bulb, but that species has a pale greenish yellow cap and does not discolor reddish brown.

REFERENCES: Atkinson, 1918. (Krieger, 1927; Smith, 1949; Smith, Smith & Weber, 1979; Arora, 1986; Jenkins, 1986; Phillips, 1991/2005; Lincoff, 1992; Metzler & Metzler, 1992; Barron, 1999; Roody, 2003; Tulloss, 2004; McNeil, 2006; Miller & Miller, 2006.) Herb. Kuo 06229501, 07200203, 07200204, 07200205, 06120301, 07160703.

Further Online Information:

Amanita brunnescens at Tulloss's Studies in Amanita
Amanita brunnescens at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2002, June). Amanita brunnescens. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita_brunnescens.html