Tylopilus alboater

[ Basidiomycetes > Boletales > Boletaceae > Tylopilus . . . ]

by Michael Kuo

This easy-to-recognize Tylopilus has a blackish, velvety cap and a dark, smooth stem. Its pore surface is initially white; later it becomes pinkish and bruises promptly red, then black. It has a mild taste, unlike the many bitter Tylopilus species, and its flesh turns pink, then slowly grayish on exposure to air. It is mycorrhizal with hardwoods in eastern North America.

Description:

Ecology: Mycorrhizal with hardwoods (especially oaks); growing alone or scattered; summer and fall; widely distributed east of the Rocky Mountains.

Cap: 3-15 cm; convex, becoming broadly convex or flat; dry; velvety; sometimes with a white dusting when young; black or dark grayish brown; in my experience, often darkening on handling.

Pore Surface: Whitish becoming pinkish; bruising red, then brown to black; pores angular, 2 per mm; tubes to 1 cm deep.

Stem: 4-10 cm long; 2-4 cm thick; more or less equal, or enlarging towards base; colored like the cap or paler; sometimes with a white dusting; fairly smooth; not reticulate or merely finely so near the apex; in my experience, often darkening on handling.

Flesh: Thick and white; discoloring pinkish on exposure to air, then turning slowly grayish; black in the stem base.

Odor and Taste: Not distinctive.

Chemical Reactions: Flesh greenish to bluish with iron salts; pinkish orange with KOH; olive, then brownish orange with ammonia. Cap orangish with KOH; negative with iron salts or ammonia.

Spore Print: Pink.

Microscopic Features: Spores 7-11 x 3.5-5 µ; fusiform to subfusiform; smooth. Pileipellis a cutis of elements 4-7 µ wide, smoky yellowish in KOH.

REFERENCES: (Schweinitz, 1822) Murrill, 1909. (Saccardo, 1888; Coker & Beers, 1943; Singer, 1947; Snell & Dick, 1970; Smith & Thiers, 1971; Smith, Smith & Weber, 1981; Weber & Smith, 1985; Phillips, 1991/2005; Lincoff, 1992; Both, 1993; Bessette, Roody & Bessette, 2000; Roody, 2003; Miller & Miller, 2006; Kuo, 2007; Binion et al., 2008.) Herb. Kuo 07230308, 09300301, 07230402, 07270401, 07160702.

Further Online Information:

Tylopilus alboater in Smith & Thiers, 1971
Tylopilus alboater at Roger's Mushrooms

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Cite this page as:

Kuo, M. (2003, September). Tylopilus alboater. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/tylopilus_alboater.html