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

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THE BOLETES OF MICHIGAN

demum vinacei; stipes 8-14 cm longus, 1-4 cm crassus, clavatus, albidus,
tactu sordide brunneus, sursum indistincte reticulatus; sporae 10-15 X
3-4.5 (5)/#. Specimen typicum in Herb. Univ. Mich. conservatum est;
prope Highlands, legit Smith n. 64301.
Pileus 6-12 (15) cm broad, broadly convex with an incurved sterile
margin, expanding to broadly convex or finally nearly plane; surface dry
and uneven, often wrinkled as in parchment paper, unpolished to
pruinose, whitish ("tilleul-buff") young, remaining so or in age slowly
becoming pale tan ("pinkish buff"), slowly staining brown where
injured. Context thick, hard, white, discoloring brown around larval
tunnels, odor fungoid, taste very bitter, FeSO4 pinkish on young pilei;
KOH causing no color change at all.
Tubes deeply depressed around the stipe or free, white, becoming
vinaceous, 10-15 mm deep; pores white then pinkish vinaceous, round
or nearly so, small (1-2 per mm).
Stipe 8-14 cm long, 1-4 cm thick, enlarged downward (clavate),
solid, white within, slowly brownish where cut, yellow-brown around
larval tunnels; surface white, staining dingy yellow-brown where handled,
apex faintly reticulate, base whitish and practically glabrous.
Spore deposit "fawn color" (dingy vinaceous); spores 10-15 X
3-4.4 (5)1i, in profile elongate-inequilateral with a distinct suprahilar
depression, in face view narrowly boat-shaped to nearly oblong, smooth,
wall only slightly thickened, mostly yellowish in Melzer's but a few dark
rusty brown, nearly hyaline in KOH.
Basidia 26-32 X 9-12 u, clavate, hyaline in KOH, yellowish in
Melzer's. Pleurocystidia 36-50 X 8-13 u, narrowly fusoid-ventricose with
narrow neck and subacute apex, hyaline, thin-walled, readily collapsing,
content not distinctive in KOH, in Melzer's those near the pores with
deep cinnabar-red oily-globular content and many large red globules free
in the mount, farther back from the edge more of the cystidia having
merely a pinkish more homogeneous content.
Tube trama of slightly divergent hyphae which in the region near
the pores when revived in Melzer's have granular to globular content red
to orange and this also present in the basidia and basidioles to some
extent. Pileus cutis of narrow (2-4.5,) interwoven hyaline smooth,
hyphae not gelatinous in KOH, the layer very thin in older pilei. Context hyphae 7-12,u wide, tubular to somewhat inflated and with dark
red homogeneous content as revived in Melzer's. Clamp connections
absent.
Habit, habitat, and distribution.-Gregarious under oak during late
summer and fall in the southern part of the state, rare but abundant
during seasons with heavy rainfall in late August.