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

BOLETUS

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to 12-17 u and globose or nearly so, the terminal cell of an element
often reduced in size or in the form of an obtuse flexuous hyphal tip;
walls thin and with some adhering dextrinoid debris occasionally, content in Melzer's ochraceous-orange-brown and homogeneous, in KOH the
content "colloidal." Hyphae of context with some orange content in
Melzer's but often mostly hyaline especially in mature basidiocarps,
interwoven, thin-walled. Clamp connections absent.
Habit, habitat, and distribution. -Under oak and in mixed oak-pine
forests, late summer and fall during wet seasons, common at times.
Observations.-The distinguishing features are the lack of blue
stains anywhere, the inflated cells in the pileus trichodermium and their
orange-brown content in Melzer's, the fleeting-amyloid reaction of the
spores, the green then fuscous NH4OH reaction of the fresh pileus
cuticle, and the strong FeSO4 reaction. In the material we have studied
from Michigan the formation of the needle-like crystals was not a constant feature. However, at times it is very pronounced. This species has
the stature of Boletus fraternus, which is strictly in accord with Peck's
original description. The type has been studied and a complete description of it follows:
"Pileus convex, dry, subglabrous, yellowish brown or grayish
brown, sometimes tinged with red especially in the center, flesh pallid or
yellowish; tubes bright yellow, plane or somewhat convex when old,
adnate, their mouths angular to subrotund, often larger near the stem;
stem nearly equal, sometimes abruptly pointed at the base, glabrous,
pallid or yellowish, coarsely reticulated either wholly or at the top only;
spores oblong or subfusiform, yellowish-brown tinged with green,.00045-.0005 in. long,.00016-.0002 broad.
"Pileus 1.5-3 in. broad; stem 1.5-2.5 in. long, 3 to 5 lines thick."
Microscopic characters from the type (by Smith): Spores
11-13 X 44.5 pu, smooth, apex lacking a pore or a thin spot, color in
KOH ochraceous to pallid yellowish, in Melzer's merely slightly tan;
shape in face view narrowly subovate to subfusoid, in profile obscurely
to somewhat inequilateral, wall about 0.3 g thick.
Basidia 4-spored, mostly gelatinized. Pleurocystidia if present gelatinized and content not homogeneous. Caulocystidia not studied.
Tube trama of the Xerocomus subtype (weakly divergent), completely inamyloid, large wormlike laticiferous elements present with
yellow amorphous content in KOH or Melzer's.
Pileus cuticle a collapsed trichodermium of wide hyphae (8-15 g)
with many short often inflated cells and with bright yellow content in
KOH, the pigment soon fading, walls thin and smooth, end-cell elongate