Amanita muscaria var. formosa

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by Michael Kuo

This variety of Amanita muscaria is distinguished by its yellow, rather than red, cap. Its other trademark features are shared with the red version: white warts on the cap, a sturdy white ring, and a distinctive stem base that has several shaggy "zones" above a basal bulb. Though its range extends across North America, it is more commonly found in the east.

In northern Michigan Amanita muscaria var. formosa fruits in great quantities, regularly attaining dinner-plate size, while the red Amanita muscaria is rare or absent. Since it is a fairly gregarious mushroom, one often finds large troops of these mammoth Amanitas lurking under quaking aspen at the edges of fields.

Description:

Ecology: Mycorrhizal with hardwoods and conifers; growing alone or gregariously, sometimes in fairy rings; summer and fall; widely distributed in North America, but most common in the northeast.

Cap: 4-16 cm, convex, becoming broadly convex to flat in age; smooth underneath the warts; sticky when wet or fresh; pale yellow to orange yellow, fading with age; with many cottony white warts; the margin usually slightly lined.

Gills: Free from the stem; white; crowded.

Stem: 4-15 cm long; 1-3 cm thick; more or less equal, or frequently tapering to apex and flaring to an enlarged base; typically somewhat shaggy; white; with a persistent, whitish, skirtlike ring; with a prominent rim, and (often) concentric rim-like bands at the top of the base.

Flesh: White throughout.

Spore Print: White.

Microscopic Features: Spores 9-13 x 6-8 µ; smooth; broadly elliptical; nonamyloid.

REFERENCES: (Persoon, 1799) Saccardo, 1887. (Thiers, 1982; Arora, 1986; Jenkins, 1986; Phillips, 1991/2005; Lincoff, 1992; Barron, 1999; Roody, 2003; Tulloss, 2003; McNeil, 2006.) Herb. Kuo 09019512, 11220403, 11220406, 09150712.

According to Amanita expert Rodham Tulloss (2003), the correct name for the variant described above is Amanita muscaria var. guessowii; see the link below.

Amanita muscaria var. flavivolvata has a bright red cap; Amanita muscaria var. alba has a white cap.

Further Online Information:

Amanita muscaria var. guessowii at Tulloss's Studies in Amanita
Amanita muscaria var. formosa at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2002, September). Amanita muscaria var. formosa. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita_muscaria_formosa.html