Boletus griseus

[ Basidiomycetes > Boletales > Boletaceae > Boletus . . . ]

by Michael Kuo

Boletus griseus is not the most memorable of boletes, but it is fairly common and relatively easy to identify. The stem is the most distinctive macrofeature; it is more or less even in width, reticulate with a yellowish to brownish pattern that darkens when the mushroom is handled, it stains and bruises yellow when mature, especially in the lower half, and it is frequently curved near the base.

As far as edibility is concerned, Boletus griseus is edible and not bad, when you can find specimens that haven't been set upon by a host of critters, which is not often.

Description:

Ecology: Mycorrhizal with oaks and other hardwoods; growing alone, scattered, or gregariously; summer and fall; widely distributed east of the Rockies, perhaps also in the southwest.

Cap: 5-14 cm, convex to broadly convex in age; dry; with tiny, pressed-down, grayish fibers (use a hand lens) over a pale to gray to brownish gray base color; darkening with age and sometimes on handling.

Pore Surface: Whitish to dirty gray; not bruising or bruising brown or darker gray; tubes to 20 mm deep.

Stem: 4-14.5 cm long; 1-3.5 cm thick; more or less equal; frequently (but not always) curved near the base as in the illustrations; whitish, staining yellow from the base upwards as it ages; prominently and widely reticulate (usually over the whole stem) with a yellowish reticulum that becomes brownish or blackish in age or when handled; solid.

Flesh: White, not staining or staining dingy red or brownish on exposure.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia negative on cap surface; negative to pale pinkish gray on flesh. KOH negative to olive on cap surface; negative to pinkish or orangish on flesh. Iron salts negative on cap surface; negative to bluish gray on flesh.

Spore Print: Pinkish brown to olive brown.

Microscopic Features: Spores 9-13 x 3-5 µ; smooth; oblong.

REFERENCES: Frost, 1878. (Coker & Beers, 1943; Singer, 1947; Smith & Thiers, 1971; Smith, Smith & Weber, 1981; Weber & Smith, 1985; Phillips, 1991/2005; Metzler & Metzler, 1992; Both, 1993; Barron, 1999; Bessette, Roody & Bessette, 2000; Roody, 2003; McNeil, 2006; Kuo, 2007; Ortiz-Santana et al., 2007.) Herb. Kuo 07079504, 06170201, 08290500, 06300706.

According to Smith & Thiers (1971), Boletus griseus is closely related to Boletus ornatipes. When the two mushrooms appear in their "pure" forms, they are clearly distinct and not likely to be mistaken for each other. But, in my experience, forms of both mushrooms can be found approaching each other, and I have found specimens so mixed in their features that I gave up entirely trying to decide which of the two I had found.

Further Online Information:

Boletus griseus in Smith & Thiers, 1971
Boletus griseus at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2002, June). Boletus griseus. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletus_griseus.html