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

348

THE BOLETES OF MICHIGAN

even. Context dull yellow but quickly blue when injured, and rather
soon fading on stained portions to olivaceous.
Tubes about 1.5 cm deep, depressed around the stipe, yellow with
the pores dull red, staining blue when injured; as dried the sides dull
olivaceous.
Stipe 7-9 cm long, 1-2 cm thick, equal to pinched off at the base,
solid, yellowish within and staining like the pileus, in the base dark
vinaceous and this tint still evident as dried; surface with a distinct
netlike reticulum over the upper half, yellowish above, vinaceous-red
below, the reticulum faintly reddish.
Spores 9-12.5 X 5.5-6 j, smooth, wall -0.2. thick, lacking apical
differentiation; shape in profile subelliptic to very obscurely inequilateral
in face view narrowly elliptic to slightly ovate, color dull yellow-brown
in KOH or Melzer's, a very slight fleeting-amyloid reaction present.
Basidia 4-spored. Pleurocystidia scattered, clavate to fusoid, 28-37
X 9-13 u, in Melzer's with a dark dingy brown reticulate amorphous
content, dull fulvous in KOH. Caulocystidia in patches, 22-46 (60) X
7-12 (15) u, clavate, clavate-mucronate, or fusoid-ventricose, often with
ochraceous to fulvous content as seen revived in KOH.
Pileus cuticle a trichodermium of hyphae 3-6 l wide, tubular,
end-cells tubular or at apex slightly tapered, content often in wads or
masses of reddish pigment as revived in Melzer's (ochraceous-brown as
revived in KOH), walls smooth and slightly gelatinous as revived in
KOH, a yellow pigment diffusing in the mount. Clamp connections
absent.
Habit, habitat, and distribution.-Solitary in open oak woods,
George Reserve, near Pinckney, July, 1967, Florence Hoseney 509.
Observations.-This species differs from B. luridus in distinctly
shorter spores and the dark brown pleurocystidia when revived in
Melzer's. It has the stature and the same low type of reticulum as B.
rhodoxanthus. However, it appears most similar to B. satanoides
(Smotlacha, Cesk. Houb. 2:29. 1920). Their spore features appear to
distinguish them, however: 11-16 X 5-6.5 uI for B. satanoides and 9-12
X 5.5-6 Li for B. vinaceobasis as for size, and in shape "schmal mandelformig mit deutlicher suprahilar-depression" for the former and subelliptic to obscurely inequilateral for the latter, which amounts to a
significant difference in the appearance of the spore in profile view. Also
the stipe in Smotlacha's species appears to be much brighter yellow.