Boletus atkinsonii

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by Michael Kuo

This eastern member of the Boletus edulis species cluster is distinguished by its roughened and somewhat wrinkled cap surface, its preference for hardwoods, and its characteristic reactions to chemicals (see below). It is extremely close to Boletus variipes--close enough that one might reasonably doubt whether the two species (as well as a few others, including the recently-described Boletus nobilissimus) are "truly" different mushrooms, or merely ecotypes of the same species. Perhaps, one day, DNA studies will penetrate the genus Boletus deeply enough to resolve such questions.

Though I have not tried it, Boletus atkinsonii is undoubtedly a wonderful edible. I have only found it in small numbers, and have had to study what specimens I've collected. However, my mushrooming pal Bob Zordani assures me the studying days are over for Boletus atkinsonii, and the next ones will be eaten, come hell or high water.

Description:

Ecology: Mycorrhizal with hardwoods, especially oaks and beech; growing alone, scattered, or gregariously; summer and fall; widely distributed in eastern North America.

Cap: 4-20 cm; convex, becoming broadly convex or almost flat; dry; finely roughened; somewhat wrinkled; often becoming cracked in age; grayish brown to yellowish brown; margin even.

Pore Surface: White when young, becoming yellowish or brownish yellow; not bruising; 1-3 pores per mm; tubes 5-12 mm deep.

Stem: 5-12 cm long; 1-3 cm thick; more or less equal, or enlarging to base; dry; solid; whitish or brownish; prominently reticulate with brownish reticulation.

Flesh: White; not staining on exposure.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia flashing purple to magenta, then resolving to purplish or brownish on cap surface; negative on flesh. KOH brown to pale orange on cap surface--sometimes flashing purplish first; negative on flesh. Iron salts negative on cap surface and flesh.

Spore Print: Yellowish brown.

Microscopic Features: Spores 10-14 x 3.5-5 µ; smooth; more or less elliptical, or almost spindle-shaped.

REFERENCES: Peck, 1905. (Snell & Dick, 1970; Smith & Thiers, 1971; Both, 1993; Bessette, Roody & Bessette, 2000.) Herb. Kuo 07220321, 09190302, 06300711, 07060702.

Further Online Information:

Boletus atkinsonii in Smith & Thiers, 1971

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Cite this page as:

Kuo, M. (2003, December). Boletus atkinsonii. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletus_atkinsonii.html