Boletus barrowsii

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

by Michael Kuo

This western species is a whitish member of the Boletus edulis group. It is found primarily under ponderosa pine in the Southwest, and under coast live oak on the West Coast. Like other members of the species group it features a robust, reticulate stem and a non-bruising pore surface. Its flesh does not turn to blue when sliced. Aside from its colors, it differs from other edulis-like species in not having a clearly defined cap skin (a "cuticle" in Mycologese).

Description:

Ecology: Mycorrhizal with ponderosa pine and occasionally with spruces in the Southwest and in Colorado--and with coast live oak on the West Coast; growing alone, scattered, or gregariously; summer and fall (monsoon season) in the Southwest--fall and winter on the West Coast; ranging as far north as British Columbia.

Cap: 5-20 cm; convex, becoming broadly convex or almost flat; dry; dull; smooth; whitish.

Pore Surface: Whitish and appearing "stuffed" when young, becoming yellow or olive yellow; not bruising; 1-2 pores per mm at maturity; tubes to 2 cm deep.

Stem: 6-20 cm long; 2-6 cm thick; equal, or frequently club-shaped, especially when young; solid; whitish; not bruising, but sometimes developing brownish hues; finely reticulate.

Flesh: White; not staining on exposure.

Odor and Taste: Pleasant; not distinctive.

Chemical Reactions: Ammonia orange on cap surface; yellow on flesh. Iron salts gray on flesh.

Spore Print: Olive brown.

Microscopic Features: Spores 13-15 x 4-5 µ; smooth; subfusiform; yellowish in KOH. Hymenial cystidia mostly cylindric to subclavate; hyaline in KOH; to about 50 x 10 µ. Pileipellis a cutis of cylindric hyphae 4-6 µ wide.

REFERENCES: Thiers & Smith, 1976. (Thiers, 1976; Arora, 1986; States, 1990; Phillips, 1991/2005; Both, 1993; Evenson, 1997; Bessette, Roody & Bessette, 2000; Arora, 2008; Trudell & Ammirati, 2009.)

Further Online Information:

Boletus barrowsii in Thiers & Smith, 1976
Boletus barrowsii at Tom Volk's Fungi
Boletus barrowsii at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2007, December). Boletus barrowsii. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletus_barrowsii.html