Major Groups > Boletes > Boletus > Boletus projectellus


Boletus projectellus

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

by Michael Kuo

Widely distributed under pines in eastern North America from Canada to Mexico, Boletus projectellus features a proportionally long stem with elaborate ridges, and a reddish brown to brown cap with a projecting sterile margin (for which the species is named).


Ecology: Mycorrhizal with pines; apparently capable of switching hosts within the genus Pinus fairly easily (Both, 1993); growing alone, scattered, or gregariously; late summer and fall; widely distributed east of the Great Plains.

Cap: 3-12 cm; convex, sometimes becoming broadly convex or nearly flat; dry; finely velvety or bald; often cracking with age; reddish brown to purplish brown or brown; with a projecting sterile margin that may become somewhat tattered.

Pore Surface: Often depressed around stem; yellow to olive yellow; not bruising, or bruising yellow; with round pores measuring 1-2 mm across at maturity; tubes to about 2.5 cm deep.

Stem: 7-15 cm long; 1-2 cm thick; slightly tapered to apex, or more or less equal; dry; solid; buff to pinkish brown or reddish brown; coarsely but shallowly ridged and/or reticulate over the top half or nearly overall; when fresh often sticky, especially toward the base; basal mycelium prominent and white.

Flesh: Whitish to pinkish; not staining, or staining slowly and faintly brownish on exposure.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia negative on cap and flesh. KOH negative on cap and flesh. Iron salts dull olive on cap; grayish on flesh.

Spore Print: Olive brown.

Microscopic Features: Spores 18-33 x 7.5-12 µ; smooth; subfusoid; with thick walls; golden in KOH.

REFERENCES: (Murrill) Murrill, 1938. (Coker & Beers, 1943; Singer, 1945; Snell & Dick, 1970; Smith & Thiers, 1971; Grund & Harrison, 1976; Smith, Smith & Weber, 1981; Phillips, 1991/2005; Both, 1993; Bessette, Roody & Bessette, 2000; Roody, 2003.) Herb. Kuo 10170909.

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Boletus projectellus

Boletus projectellus

Boletus projectellus

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Kuo, M. (2010, April). Boletus projectellus. Retrieved from the MushroomExpert.Com Web site: