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

BOLETUS

259

brown in KOH, content granular and in Melzer's dull red, nearly hyaline
in KOtI. Clamp connections absent.
Habit, habitat, and distribution.-Solitary on hummocks, hardwood
slashings, Emerson, Chippewa County, July 27, 1967, Smith 74678.
Observations.-This is an autonomous species by virtue of the
color of the pileus (date-brown), the heavily incrusted elements of the
pileus trichodermium, and their red content in Melzer's. It is one of the
small species which occurs singly and is easily overlooked when the
collecting is good.
135. Boletus chrysenteron Fries
Epicr. Syst. Myc. p. 415. 1838
Xerocomus chrysenteron (Fries) Quelet, Fl. Myc. Fr. p. 418. 1888.
var. chrysenteron
Illus. PI. 105.
Pileus 3-8 cm broad, convex becoming broadly convex or finally
nearly plane; surface dry and evenly velutinous to subtomentose when
young, the epicutis areolate in age exposing the context which soon
reddens; color when young dark olive to olive-brown, paler olive to
olive-gray in age and then often with a red marginal zone, rarely becoming reddish overall. Context whitish at very first but soon yellowish,
slowly staining bluish when cut, becoming lemon-yellow in FeSO4, in
KOH buff colored, very soft and punky, odor and taste mild; on the
cutis blackish with KOH, no reaction with FeSO4 and brownish with
NH40H.
Tubes up to 5-10 mm deep, depressed around the stipe, bright
yellow, slowly becoming "Isabella color" in age, blue when wounded;
pores about 1 mm in diameter, irregular in outline, bright yellow young,
in age reddish over some areas, mostly splitting lengthwise when the
pileus is broken downward.
Stipe 4-6 cm long, 5-10 mm thick, equal or narrowed downward,
solid, yellowish to pallid at apex, purplish red in the base, staining
bluish green where injured; surface pallid becoming bright yellow, pinkish red below, scurfy to pruinose overall and at times with longitudinal
lines or ridges but not reticulate, basal mycelium white.
Spore deposit olive to olive-brown; spores 9-13 X 3.5-4.5 (5) u,
smooth, oblong to boat-shaped in face view, narrowly inequilteral in
profile, bright yellow in KOH, dull grayish yellow in Melzer's, lsmooth,
lacking an apical pore.