B. radi´cans Pers.—radix, a root. Pileus convex, dry, subtomentose, olivaceous-cinereus, becoming pale-yellowish, the margin thin, involute. Flesh pale-yellow, instantly changing to dark blue, taste bitterish. Tubes adnate, their mouths large, unequal, lemon-yellow. Stem even, tapering downward and radicating, flocculose with a reddish bloom, pale-yellow, becoming naked and dark with a touch.
Pileus 2–3 in. broad. Stem 2 in. long, 6 lines thick.
Woods. Ohio, Morgan.
Of the American plant Mr. Morgan says that the pileus is quite firm and dry, becomes reddish or brownish-yellow and nearly glabrous, that the flesh is pale-yellow, but that he has not observed any bluish tinge, and that the spores are olive, fusiform, 10–12.5×5µ. Those of the European plant have been described as very pale ocher, almost white, 6µ long, 3µ broad. Peck, Boleti of the U.S.
Near Bryn Mawr, Pa. W.C. Alderson, 1894.
Several specimens brought to me were eaten. The change in color of flesh was instantaneous upon exposure to the air. Taste strong and raw rather than bitterish. The caps alone were cooked, and dish marked “fine.”
B. muta´bilis Morg.—changeable. Jour. Cin. Soc. Nat. Sci., Vol. VII. Pileus convex, then plane or depressed, compact, dry, subtomentose, brown. Flesh bright-yellow, promptly changing to blue where wounded. Tubes adnate or subdecurrent, their mouths large, angular, unequal, some of them compound, yellow changing to greenish yellow and quickly becoming blue where wounded. Stem stout, solid, flexuous, subsulcate, yellowish beneath the brown dot-like scales, bright yellow within. Spores olive, fusiform, 12–13×5µ.
Pileus 2.5–4 in. broad. Stem 2–3 in. long, 6 lines thick.
Thick woods. Ohio, Morgan.
A shade of yellow sometimes appears beneath the brown of the pileus, and as the plants grow old the pileus becomes blackish, glabrous and shining. The stem increases in thickness above and downward. Peck, Boleti of the U.S.