Major Groups > Boletes > Boletus > Boletus zelleri


Boletus zelleri

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

by Michael Kuo

When fresh and young, the West Coast's Boletus zelleri is a stunning mushroom with a blackish brown cap, a red and yellow stem, and a yellow pore surface. With age, it begins to lose some of its pizzazz, but still retains much of its original glory. It is one of those boletes that can't make up its mind whether or not it wants to bruise and stain blue, so do not rely heavily on this character for identification--though I can't imagine you would need to, since the mushroom is so distinctive.


Ecology: Often growing under conifers, and sometimes under hardwoods. Presumably mycorrhizal, since it is a species of Boletus--but reported under redwood, sometimes growing from the very rotted wood around ancient trunks, by many authors (including this one). Since no mushrooms are known to be mycorrhizal with redwoods, one wonders. Growing alone, scattered, or gregariously; fall, winter, and spring; along the West Coast.

Cap: 3-16 cm; convex, becoming broadly convex or nearly flat; dry; often conspicuously wrinkled when young; sometimes dusted with powder; somewhat velvety; often becoming cracked by maturity, with pinkish flesh showing in the cracks; black to dark brown when young, becoming olive brown or occasionally developing reddish hues.

Pore Surface: Yellow, becoming olive yellow; bruising blue--or not bruising; 1-2 pores per mm at maturity; tubes to about 1.5 cm deep.

Stem: 4-12 cm long; .5-3 cm thick; more or less equal; dry; solid; yellow or tan, with red granules overlaid--or red overall; fairly smooth, or somewhat hairy; not reticulate.

Flesh: Whitish to pale yellow; staining slowly and erratically blue on exposure, or not staining.

Odor and Taste: Not distinctive.

Chemical Reactions: Ammonia negative on cap and flesh. KOH black on cap; dark yellow on flesh. Iron salts negative on cap and flesh.

Spore Print: Olive brown.

Microscopic Features: Spores 12-16 x 4-5.5 µ; smooth; subfusoid.

REFERENCES: Murrill, 1912. (Smith, 1949; Thiers, 1975; Smith, Smith & Weber, 1981; Phillips, 1991/2005; Lincoff, 1992; Both, 1993; Bessette, Roody & Bessette, 2000; Miller & Miller, 2006; Kuo, 2007; Trudell & Ammirati, 2009.) Herb. Kuo 01130509.

This site contains no information about the edibility or toxicity of mushrooms.


Boletus zelleri

Boletus zelleri

Boletus zelleri

Boletus zelleri

Boletus zelleri

Boletus zelleri

© MushroomExpert.Com

Cite this page as:

Kuo, M. (2005, March). Boletus zelleri. Retrieved from the MushroomExpert.Com Web site: