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

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THE BOLETES OF MICHIGAN

region at first, pruinose with brownish to reddish pruina, sometimes
with coarse longitudinal ridges or obscurely widely reticulated.
Spore deposit olive to olive-brown; spores (9) 11-14 X 4.5-5 g,
smooth, oblong to ventricose in face view, narrowly inequilateral with a
broad suprahilar depression in profile view, dingy ochraceous in KOH,
greenish gray to yellowish in Melzer's, finally weakly dextrinoid, no
apical pore evident.
Basidia 4-spored, 36-40 X 10-12.5 u, clavate, pedicel narrow.
Pleurocystidia 38-50 X 9-14 pg, fusoid-ventricose to mucronate, content
homogeneous and hyaline, walls thin and smooth. Cheilocystidia clavate
to subfusoid, yellow in mass from pigment in the wall, 36-48 X 9-14 g.
Caulocystidia fasciculate, clavate, thin-walled, 32-56 X 8-16 j,, yellow in
KOH but content homogeneous. Tube trama parallel as revived in KOH,
the hyphae long, straight, and 7-12 p wide.
Pileus trichodermium of long tangled but more or less upright
hyphae 6-12, wide, the walls smooth and hyaline in KOH and the
content colloidal, content ochraceous or orange-brown in Melzer's, the
cells near the tips shorter than the remainder but 2-4 times longer than
broad, no inflated cells seen, the tips agglutinating into a layer (as revived in KOH or Melzer's). Context hyphae near the trichodermium with
orange-brown homogeneous content in Melzer's, smooth or with some
incrusting debris in the region of the subcutis as well as the lower cells
of the elements of the trichodermium but this disappearing in KOH.
Clamp connections absent.
Habit, habitat, and distribution.-Gregarious especially along wet
road banks, its abundance in the state has not been accurately ascertained.
132a. Boletus spadiceus var. gracilis var. nov.
A typo differt: Pileus 3-8 cm latus; stipes 3-6 cm longus, 5 -10 mm crassus; sporae 10-12 (13) X 4.5-5.5 M. Typus Smith 75911
(MICH).
Pileus 3-8 cm broad, expanding to broadly convex or nearly plane,
margin fertile and even; surface dry and velvety-subtomentose, in age or
when wet appearing matted-fibrillose, color dingy yellow-brown ("Saccardo's umber" to "Prout's brown"), when wet with a dull red tinge,
when dried with a subgranulose texture. Context whitish in midportion
and bright yellow near the tubes, when mature with a brown to reddish
brown line under the cuticle; odor and taste not distinctive; FeS04 no
reaction, NH40H on cuticle giving a green flash and then turning reddish brown; staining blue when bruised near the pileus margin.