The boletes of Michigan, by Alexander H. Smith and Harry D. Thiers.

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THE BOLETES OF MICHIGAN

154. Boletus piperatus Fries
Syst. Mycol. 1:388. 1821
Viscipellis piperata (Fries) Quelet, Enchir. Fung. p. 157. 1886.
Ixocomus piperatus (Fries) Quelet, Flor. Myc. Fr. p. 414. 1888.
Chalciporus piperatus (Fries) Bataille, Bolets, p. 19. 1908.
Illus. Pls. 114-15.
Pileus (1.5) 2-5 (9) cm broad, obtuse to convex, becoming nearly
plane to plano-convex to occasionally subumbonate or margin turned up
slightly in age, margin entire, incurved when young, surface dry becoming subviscid, mostly appearing unpolished, pellicle typically somewhat
separable, glabrous to somewhat fibrillose-streaked or appressed-squamulose, often glabrous with age, at times areolate; clay color to some shade
of yellow-brown or orange-cinnamon ("clay color," "cinnamon-buff,"
"buckthorn-brown," "ochraceous-tawny," "tawny," or "orange-cinnamon"), often darker on the disc to rusty cinnamon. Context up to 1 cm
thick, firm, pale yellow ("warm buff'), in age often with a slight rose
tint or distinctly vinaceous above the tubes, becoming dingy vinaceousbuff in age, soft and subgelatinous when old, taste very sharply and
distinctly acrid, odor not distinctive, with FeSO4 the line above the
tubes is grayish, in KOH no reaction but on the cutis of the pileus
staining it dark red-brown, NH40H violaceous-fuscous on context. The
pileus cutis stains waxed-paper red.
Tubes adnate to subdecurrent or only faintly depressed, short
(3-10 mm deep), dingy ochraceous but slowly becoming reddish in age
("ocher-yellow" to "ochraceous-tawny" to "tawny-olive" and finally
with vinaceous-red tones); pores angular, unequal, averaging 2 per mm,
dissepiments thin, dull yellow when young, soon more or less cinnamon
and in age finally distinctly red to brick-red, not staining appreciably
when injured (merely dark brown).
Stipe (2) 4-10 (12) cm long, (3) 4-10 (15) mm thick, solid,
lemon-yellow within, unchanging when injured; surface reddish cinnamon from pruina, ground color yellow, in age with lines from the tubes
extending down the apical portion, base bright yellow from a coating of
bright yellow mycelium, negative when tested with FeS04.
Spore deposit "Sayal-brown" (dull cinnamon); spores (8.5) 9-12 X
4-5 J, smooth, narrowly fusiform in face view, obscurely inequilateral in
profile, with a hyaline sheath, olivaceous-hyaline to dingy ochraceous in
KOH, rusty brown in Melzer's.