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

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THE BOLETES OF MICHIGAN

moist but soon dry and appearing merely unpolished to finely tomentose, dingy pale cinnamon in color ("Sayal-brown," "snuff-brown,"
"Verona-brown," or rarely as dark as "warm sepia" when young). Context pure white fresh, slowly assuming a vinaceous-buff tint when injured; taste mild, odor none.
Tubes 9-12 mm deep, adnate at first, then somewhat depressed,
white when young but soon "vinaceous-buff" or darker vinaceous and
when mature staining brown where bruised or touched; pores concolorous with sides, stained brown in age, 2-2.5 per mm, angular, dissepiments
entire.
Stipe 4-10 cm long, 1-2.5 (3.5) cm thick at apex, clavate becoming equal or equal from the first, solid, whitish within, brownish where
bruised; surface minutely furfuraceous, finely reticulate above in addition, pallid above, soon brown below and especially so after being
handled.
Spore deposit vinaceous to vinaceous-fawn; spores 10-13 X 3-4 It,
nearly hyaline in KOH, in Melzer's pale tan or a few reddish tawny, wall
only very slightly thickened, smooth, narrowly subfusiform in face view,
narrowly inequilateral with a broad suprahilar depression in profile, wall
about 0.2 / thick.
Basidia 18-25 X 6.5-8 I, 4-spored, hyaline in KOH. Pleurocystidia
scattered, ventricose with a projecting slender neck, content lemon to
golden yellow in KOH, somewhat dextrinoid in Melzer's, thin-walled,
lacking incrustations. Pileus cuticle a tangled trichodermium of hyphae
3-9 J wide, thin-walled, collapsing, smooth, hyaline or with ochraceous
content in KOH (as in some oleiferous hyphae), the end-cells mostly
cylindric and obtuse, their content often dextrinoid; both the hyphae of
the cuticle and the context reddish to some extent in Melzer's. Clamp
connections absent.
Habit, habitat, and distribution.-Gregarious to scattered in low
hardwoods in southern Michigan after heavy rains in July and August,
fairly common if the weather is favorable.
Observations.-Boletus indecisus Peck differs from Singer's concept
of T. ferrugineus in having vinaceous spores in a deposit, not "Isabella
color" to "wood-brown." We have as yet not found a species in Michigan answering his description. The pleurocystidia of T. indecisus are not
as strongly dextrinoid as in T. rubrobrunneus. The latter differs further
in a very bitter taste and in developing olive stains on the stipe from
handling. The stipe of T. indecisus is never as reticulate as in T. felleus:
in Michigan, in fact, one usually must observe the apex rather closely to
see it at all.