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

APPENDIX
The following type studies were made in the course of the Michigan project and are included here as a help to other workers since they
clarify species concepts often in rather important details. The original
descriptions are given for the convenience of the user.
Boletus caespitosus Peck, Torrey Club Bull. 27:17. 1900
Illus. Figs. 115-17.
Pileus broadly convex, to nearly plane, at times slightly concave
from the margin becoming elevated, even, brown or blackish brown, the
margin often slightly paler or reddish brown. Context slightly tinged red.
Tubes adnate or slightly decurrent, yellow, their mouths rather large,
angular, concolorous. Stem short, even, solid, glabrous, tapering upward,
brown or reddish brown.
Type study. Spores 9-12 X 4-5 g, smooth, thin-walled, lacking an
apical pore, shape in face view narrowly ovate to subelliptic, in profile
obscurely inequilateral, yellowish in Melzer's, yellowish in KOH, no sign
of any amyloid reaction.
Basidia 4-spored, 24-30 X 7-9,, narrowly clavate, yellowish hyaline in KOH or Melzer's. Pleurocystidia scattered, 46-82 X 7-15 #, narrowly fusoid-ventricose with a long pedicel, tapered to an acute or subacute apex, thin-walled, smooth, content "empty" in KOH or Melzer's.
Tube trama of the Boletus subtype, yellowish hyaline throughout
in Melzer's. Pileus cutis a tangled layer of hyphae 4-7 p wide, tubular
but curved and intertwining, walls thin, smooth and hyaline, content
homogeneous and dull orange in Melzer's for the most part; hyphae of
context merely ochraceous in Melzer's; end-cells of cuticular hyphae
tubular with blunt apex or slightly tapered to the apex, walls smooth
and cell content ochraceous or orange in Melzer's. Clamp connections
none.
Notes. B. caespitosus lacks the features of Pulveroboletus as outlined by Singer (1962). In our estimation it connects to the B. badius
group, but as boletes go it is not at all closely related to B. inflexus or
B. fistulosus.

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