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

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THE BOLETES OF MICHIGAN

tubes as bright yellow when young and brownish yellow when mature. The
features of our collection are the occasional clamps on the hyphae of
the basidiocarp, the spores 12-15 X 3.8-4.5., the yellow stains on the
stipe which is pallid to grayish at the apex, and the generally pale tan
pileus. These differences seem sufficient to justify recognizing the
species.
Stirps VARIIPES
200. Boletus atkinsoni Peck
Bull. N. Y. State Mus. 94:20. 1905 (Rept. 58)
Pileus 6-10 cm broad, convex, fleshy, expanding to nearly plane,
dry, grayish brown to yellowish brown, sometimes minutely rimosely
squamulose. Context white, taste mild. Tubes convex, plane or slightly
concave in the mass, adnate or slightly depressed around the stipe, 5-8
mm deep; the pores minute, stuffed whitish at first, soon open and
yellow or ochraceous. Stipe stout, 5-10 cm long, 1-2.5 cm thick, enlarged either above or below (or both), solid, reticulate above or nearly
overall with fine anastomosing brownish lines, pallid.
Spores 10-14 X 3.5-4.5 I, smooth, lacking an apical spot or pore;
shape in face view subfusoid, in profile obscurely inequilateral, the
suprahilar depression shallow and broad; yellowish in KOH, only slightly
browner in Melzer's, no fleeting-amyloid reaction observed, wall less
than 0.2 u thick.
Basidia 4-spored. Pleurocystidia-none found. Cheilocystidia
basidiole-like. Tube trama boletoid. Pileus cuticle a trichodermium of
agglutinated hyphae 4-7, wide, the cells elongate and tubular, the content yellowish in KOH and Melzer's, the wall with more or less colorless
patches of outer wall material resting on a gelatinous layer (much as in
Leccinum insigne, only the hyphae narrower), the end-cells scarcely inflated, usually tapered to an obtuse apex, no amyloid reactions of any
kind observed. Hyphae of subcutis ochraceous in Melzer's. Clamp connections absent.
Observations.-Our description combines Peck's original description
with data obtained from the type by Smith. We have as yet not recognized the species in our Michigan flora though the name has been used
in the sense of variipes on occasion. The roughened hyphae of the
fascicles of hyphae forming the tufts on the pileus, and the smaller
spores distinguish this species from B. variipes. The spores average
around 13 y long, whereas in B. variipes they are about 15 u long.