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

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THE BOLETES OF MICHIGAN

Tubes olive-yellow, adnate to depressed-adnate or somewhat decurrent, about 8-15 mm deep, pale yellow to greenish yellow; pores small
at first but in age 1-2 per mm, isodiametric to angular, blue when
injured and finally brownish.
Stipe 4-9 cm long, 10-22 mm thick, equal, solid, cortex yellowish
near apex, pinkish red below, pallid, becoming brownish around larval
tunnels; surface yellowish pallid at the very first at the apex, dull rosered below, slowly brownish around the base, often with a pallid bloom
at first, rarely slightly reticulate above from tube lines, surface when
fresh somewhat pruinose.
Spore deposit olive-brown; spores 10-14 X 4-5 J, in face view
suboblong to slightly ventricose, in profile narrowly inequilateral from a
slight suprahilar depression, yellow in KOH individually, greenish revived
in Melzer's, smooth, wall very slightly thickened.
Basidia 4-spored, 23-30 X 7-9 u, yellowish in KOH and in
Melzer's. Pleurocystidia scattered, 30-55 X 10-14 p, fusoid-ventricose,
filled with dark yellow-brown pigment as revived in KOH or Melzer's.
Pileus cutis a tangled mass of hyphae 5-10/, wide, with bright golden
yellow content in KOH, walls smooth and thin; end-cells not appreciably
differentiated, no amyloid particles or areas of hyphae seen and clamp
connections absent.
Habit, habitat, and distribution.-Solitary to scattered in beechmaple and hemlock-birch forests during the summer and early fall,
common during most seasons. The best fruitings seen were near the
Upper Falls in Tahquamenon Falls State Park.
Observations.-As recognized here this species is collective and deserves further study. We have spore sizes of 9-11 X 3-3.5 u, 10-14 X
4-5 p, and some 11-15 X 4-5.5 / to go along with the sizes given by
Singer (1945) who found them 11.5-18.5 (24) X 4-5 u and (from
Austria) 12.5-16.5 X 5-5.6 j. In order to resolve this situation, however,
we must have complete data on all collections in the fresh as well as
dried condition and on chemical features from fresh basidiocarps. In the
variant which gives the olive reaction with NH40H and stains weakly
vinaceous on the context when fresh if injured, the spores are 11-14 X
4-5,.
Material examined.-Alger: Mains 32-232. Cheboygan: Smith
25921, 36507, 37553; Thiers 605, 649, 732. Chippewa: Smith 72066,
72440, 74493. Emmet: Shaffer 1614; Smith 25807, 57395, 62964,
74390, 74502, 74531. Houghton: Kauffman 1906. Luce: Shaffer 1962;
N. J. Smith 158A; A. H. Smith 37085, 37179, 37229, 37434, 37468,
37822, 38145, 38341, 38517, 38658, 39285, 41651, 44110, 50238,