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

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THE BOLETES OF MICHIGAN

Tube trama of somewhat divergent hyaline tubular hyphae 6-12 u
in diameter and showing no amyloid reactions. Pileus cuticle a trichodermium of elements 10-15 g in diameter, the cells tubular to somewhat
inflated, walls thin, hyaline, not incrusted but a few with a slight gelatinous sheath, cell content merely yellowish in Melzer's, no amyloid particles seen in or outside of the cells, end-cells subclavate to subfusoid
(apex obtuse), other cells in the hypha mostly short (less than 5 times
as long as broad), and often more or less inflated. Context hyphae near
cutis having deeply colored (ochraceous to orange-ochraceous) content
in Melzer's. Clamp connections absent.
Observations.-The exceptionally long spores (15-18 /) are mostly
irregularly shaped and represent an abnormal type of spore found in
many groups of colored-spored Agaricales. They are not thin-walled and
not exceptionally wide-in fact they may be narrower than those in the
range considered typical of the species. No wide spores of the type
found in T. sordidus were found. There was no sign of ornamentation
on or in the wall of any of the spores. The basidiocarps studied were
unquestionably the same species. In the type collection the basidiocarps
are glued to pieces of paper. Smith sampled from the groups, one of
which, according to comments written on the paper, represented the
species with striate spores (Snell, 1936), and the other the group with
nonstriate spores. Both had smooth spores. The discrepancy cannot now
be explained. Certainly, Snell (Ic) found the 2 types, as he puzzled long
over this situation since it concerned spore ornamentation. Fortunately,
he cited one of his own collections as the type for B. chrysenteroides,
and the typification of the latter species is not involved. However, we
think Peck's comment about the cracks in the pileus becoming reddish
very likely applies to the specimens with ornamented spores, and this
feature is purposely left out of the above diagnosis. All the basidiocarps
now forming the holotype appear to be the same species and clearly
belong to the stirps Pseudoscaber.
We append here a detailed account of the microscopic features of
B. nebulosus for comparison (Figs. 29-30). The basidiocarps in the type
were larger than those in the type of B. fumosipes, but we believe they
are the same species.
Pileus 5-10 cm broad, convex, dry, snuff-brown or smoky brown;
context white, unchangeable; tubes convex, depressed around the stipe,
pallid or brownish becoming purplish brown where wounded, the pores
small rotund; stipe 7-10 cm long, 7-12 mm in diameter, enlarged toward
base, solid, scurfy, colored like the pileus.
Spores 12-15 (18) X 4.5-6 g, smooth, lacking an apical pore, subelliptic to somewhat inequilateral, color in KOH ochraceous, paler on