Boletus bicoloroides

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by Michael Kuo

Boletus bicoloroides is a red-capped, yellow-pored bolete that bruises blue--which is another way of saying that it has many look-alikes. However, its fairly large stature, its inrolled cap margin, and especially its stem--which is red from bottom to apex--distinguish it from Boletus bicolor, Boletus rubellus, and other confusingly similar species. The amyloid, large spores (measurements below) also distinguish Boletus bicoloroides.

Description:

Ecology: Mycorrhizal with hardwoods; summer and fall; officially recorded only from Michigan but to be expected in the Great Lakes region and perhaps northeastern North America in general. The illustrated mushrooms were collected in Quebec.

Cap: 6-15 cm; convex with an inrolled margin, becoming broadly convex with the margin still somewhat curved under; dry; smooth or finely velvety; dark red, fading in age; not typically cracking up in age (unlike the rest of us).

Pore Surface: Yellow; bruising blue; 1-2 pores per mm; tubes to 1.5 cm deep.

Stem: 6-12 cm long; 1-2 cm thick; more or less equal; solid; smooth; not reticulate; dark red from base to apex.

Flesh: Yellowish; discoloring slowly pale blue when exposed.

Odor and Taste: Not distinctive.

Chemical Reactions: Not recorded in the literature.

Spore Print: Not recorded in the literature, but probably olive brown.

Microscopic Features: Spores 14-17 x 4-5.5 µ; smooth; fusiform; strongly amyloid.

REFERENCES: Smith & Thiers, 1971. (Smith & Thiers, 1971; Both, 1993; Bessette, Roody & Bessette, 2000.) I have not collected this mushroom. I have assigned the illustrated collection to B. bicoloroides on the basis of the photos and the collection location (Quebec).

Further Online Information:

Boletus bicoloroides in Smith & Thiers, 1971

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Cite this page as:

Kuo, M. (2003, August). Boletus bicoloroides. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletus_bicoloroides.html