Amanita vaginata

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by Michael Kuo

Amanita vaginata, sometimes called the "grisette" in field guides, has a sacklike volva, a lined cap margin, and lacks a ring on its stem. A number of closely related amanitas meet this description; Amanita vaginata differs from the others in having a gray to grayish brown cap and a volva that is not tightly constricted around the stem base.

That's the theory, anyway. The reality is that you might as well call a mushroom meeting this description "Steve," if you want to be scientific. Perhaps there are a few highly variable species, and perhaps things like cap color, the "constrictedness" of the volva, and spore dimensions can accurately predict genetically distinct species--but I doubt it. More likely, there are many species going under the name "Amanita vaginata." Amanita expert Rod Tulloss treats literally dozens of unnamed, vaginata-like, numbered taxa ("species 46," and so on) in his keys to North American amanitas (2003, 2007)--all separated on morphological differences. In short, a comprehensive DNA and morphological study of well documented "Amanita vaginata" collections from across the continent will be required before there are "good names" for our North American species.

"Amanita vaginata" is often found in urban settings or in public parks where the earth has been disturbed at some point in the relatively recent past. I find it in grassy areas at the edges of woods--or in lawns that are not meticulously manicured--more frequently than I find it in the woods.

Description:

Ecology: Mycorrhizal with hardwoods and conifers; often found in disturbed ground settings in urban areas, state parks, and so on; late spring, summer and fall; widely distributed in North America.

Cap: 3-10 cm; oval, becoming convex or nearly flat with a central bump; sticky at first or when wet; gray to grayish brown; sometimes with a few scattered white to grayish patches; margin prominently lined or grooved.

Gills: Free from the stem or slightly attached to it; white; close.

Stem: 7-15 cm long; .5-2 cm thick; slightly tapering to apex; smooth, or with a few grayish scales; without a ring; the base enclosed in a sack-like, white volva that fits loosely around the stem and sometimes discolors grayish or reddish brown.

Flesh: White throughout; soft.

Spore Print: White.

Microscopic Features: Spores 8-12 µ; smooth; nearly round; inamyloid.

REFERENCES: (Bulliard, 1783) Fries, 1821. (Saccardo, 1887; Kauffman, 1918; Smith, 1949; Smith, Smith & Weber, 1979; Thiers, 1982; Weber & Smith, 1985; Arora, 1986; Jenkins, 1986; States, 1990; Phillips, 1991/2005; Lincoff, 1992; Evenson, 1997; Barron, 1999; McNeil, 2006; Miller & Miller, 2006.) Herb. Kuo 07200206, 08010205, 08290505, 07210704, 08150715, 08160713.

Amanita ceciliae, synonymous with Amanita strangulata and Amanita inaurata, has grayish patches on its brown cap, and a volva that breaks apart easily, forming flakes and patches on the stem base. As a species group it is widely distributed.

Amanita pachycolea is a very large, brown-capped species that sometimes displays color zones on the cap, and gill edges that are brownish at maturity. The volva is ample and not constricted. It is known from the Pacific Coast.

Amanita fulva is tawny and has a volva that is not constricted and often stains rusty brown. As a species group it is apparently widely distributed.

Amanita velosa is beige or orangish and usually displays a large patch on its cap. It fruits in the spring, and often can be found in grassy and open areas. Its volva is not constricted. It is known from the West Coast.

Amanita constricta has a brownish cap and a volva that is tightly "constricted" around the base of the stem, but flares outward at the top (as opposed to fitting loosely all the way down to the very bottom of the stem); it is known from California.

Amanita vaginata var. alba is pure white and has a volva that is not constricted. Its distribution is uncertain.

Amanita protecta has grayish gill edges and usually displays warts or patches. Its volva is not constricted. It is known from the West Coast.

Many of these mushrooms have previously been placed in the genera Amanitopsis and/or Vaginata.

Further Online Information:

Amanita vaginata at MykoWeb
Amanita vaginata at Roger's Mushrooms
Amanita vaginata at Fungi of Poland

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Cite this page as:

Kuo, M. (2005, March). Amanita vaginata. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/amanita_vaginata.html