Boletellus pseudochrysenteroides

[ Basidiomycetes > Boletales > Boletaceae > Boletellus . . . ]

by Michael Kuo

This widely distributed species demonstrates striking color contrasts when sliced open: the flesh is dark red in the stem and pale yellow in the cap, where it discolors indigo blue. The distinctive cap is brick red and soon cracked up, with whitish to pinkish flesh revealed in the cracks. The spores are ribbed or lined, which is why the mushroom is placed in Boletellus. This feature requires a microscope to determine, however, and the mushroom is consequently difficult to identify with keys that are arranged by genus, since it looks like it ought to belong in Boletus.

Description:

Ecology: Mycorrhizal with hardwoods, especially beech or oaks; growing alone or scattered; summer and fall; widely distributed in North America from Maine to California.

Cap: 3-10 cm; convex, becoming broadly convex or nearly flat in age; dry; soft; velvety, soon becoming prominently cracked, with whitish to pinkish flesh showing in the cracks; dark red, becoming olivaceous or remaining reddish to maturity, without olive shades; with an incurved margin.

Pore Surface: Yellowish, becoming darker yellow to olive and eventually blackish; bruising blue, then brown--or bruising blackish; pores angular, 1-1.5 mm wide; tubes to 12 mm deep.

Stem: 6-10 cm long; 1-2 cm. thick; more or less equal; dry; solid; finely hairy or scruffy; colored like the cap or paler, yellow at the apex; sometimes bruising dark brown; basal mycelium dense and whitish to yellowish.

Flesh: Pale to bright yellow in the cap, quickly staining blue on exposure; dark red in the stem and bluing somewhat, especially in the base.

Odor and Taste: Taste mild or acidic; odor not distinctive.

Chemical Reactions: Ammonia yellowish, with a gray ring, on cap; orangish on flesh. KOH negative or grayish on cap; orange on flesh. Iron salts blackish on cap; yellowish to olive on flesh.

Spore Print: Dark olive gray to brown.

Microscopic Features: Spores 11-14 x 5.5-8 µ; longitudinally grooved-ridged, with 9-12 ridges; ellipsoid or nearly so. Pileipellis a trichoderm; terminal elements cylindric with rounded to clavate apices.

REFERENCES: Smith & Thiers, 1971. (Smith, Smith & Weber, 1981; Both, 1993.) Herb. Kuo 08300206, 09010207.

Boletus chrysenteron has a brownish, cracked cap with pinkish flesh showing in the cracks, and smooth spores; Boletellus chrysenteroides has a brown cap, a distinctively punctate-hairy stem surface, and often grows from decaying oak stumps; Boletellus intermedius has a cap that develops olive shades, and has smaller spores (9-12 x 4-5 µ).

Further Online Information:

Boletellus pseudochrysenteroides in Smith & Thiers, 1971

(specimens under attack by a Hypomyces)

Spore print

Spores

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Cite this page as:

Kuo, M. (2006, November). Boletellus pseudochrysenteroides. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/boletellus_pseudochrysenteroides.html