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

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THE BOLETES OF MICHIGAN

nearly plane, margin even to slightly lobed, surface dry and pruinose to
unpolished, cuticle tending to remain intact throughout life of the
basidiocarp (not areolate or only slightly so in dry weather); color dark
brick-red to pale brick-red ("Etruscan-red"), slowly fading to pale dingy
rose and at times finally dull cinnamon, quickly yellow with a drop of
KOH. Context thick, pale yellow, instantly blue when cut, FeSO4
yellow-brown in pileus and stipe, walls of larval tunnels not appreciably
discolored, odor and taste mild.
Tubes 1-1.5 cm long, adnate becoming only slightly depressed,
bright yellow and instantly blue when injured; pores 1-2 per mm, round,
bright yellow and instantly blue when bruised and these places slowly
brownish to reddish.
Stipe 8-12 cm long, 1-3 (4) cm thick at apex, solid, equal or
enlarged downward, punky in the base, bright yellow within but soon
blue when cut but then soon fading to yellow again, surface brilliant
yellow above or overall or dull red below, apex finely and only slightly
reticulate.
Spores 10-13 X 3.5-4.5,u, suboblong to slightly ventricose in face
view, in profile slightly inequilateral from a shallow suprahilar depression, smooth, wall slightly thickened, ochraceous in KOH, greenish
gray fading to dingy yellow-brown as revived in Melzer's (fleeting-amyloid reaction present).
Basidia 4-spored, 20-26 X 7-10 u, dingy yellow in Melzer's, hyaline to yellow in KOH. Pleurocystidia scattered, 36-50 X 9-13 j, ventricose at base and the neck long and narrow (3-5 I wide), content hyaline
to dingy ochraceous in KOH or Melzer's.
The tube trama divergent from a central strand. Pileus cutis a compactly tangled layer of hyphae 3-7 g wide, with bright yellow content in
KOH and the content orange-brown in Melzer's, some hyphae more or
less coated with hyaline incrustations, the end-cell scarcely wider than
the remainder of the hypha and often narrower. Clamp connections
absent.
Habit, habitat, and distribution.-Scattered to gregarious in sandy
open woods of maple, aspen, and birch with scattered beech, during wet
seasons common throughout the state, fruiting from early summer on
into the fall.
Observations.-This is the largest species of the stirps. The reticulations at the apex of the stipe are very faint and best seen with a hand
lens. The instant change to blue on the cut flesh will aid in distinguishing it from B. miniato-olivaceus in the field. B. bicolor is a different shade of red. The blue stain in B. sensibilis is evident on well-dried