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

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THE BOLETES OF MICHIGAN

Tube trama lacking amyloid reaction of any kind, poorly revived
but apparently of the Boletus type. Pileus cuticle a cellular epithelium,
the cells vesiculose to pedicellate-clavate, 18-50 i broad, subgelatinous in
KOH (with a halo around the cell), content yellow in KOH, not distinctive in any way in Melzer's. Context hyphae not distinctive in any way
in Melzer's. Clamp connections not found.
Notes. Kauffman had 2 descriptions on separate cards. In one the
pileus was described as 6 cm. broad and in the other 10 cm. broad.
Snell's description gives 6-10 cm as the range in size of the pileus, and
it would seem to follow that these descriptions were used by Snell in
compiling the one published. A third card in which no size for the
pileus is given is now designated No. 562 (the holotype) in the University of Michigan Herbarium. The microscopic data given above are from
this collection. It was collected at Ann Arbor, August 9, 1907, by
Kauffman. In it the stipe was described as staining blue. The other 2
collections were from Sault Ste Marie, July 6, 1906, by Pennington,
and July 11, 1906, by Kauffman. In the Pennington collection the
pileus surface was bitter. Both collections consisted of one basidiocarp
each. These were from under hemlock and spruce. It is clear that Snell's
description was a composite of Kauffman's data on all 3 collections.
The holotype, in our estimation, is clearly Boletus subglabripesthe variant which stains slightly blue. The evidence for this is in the
spore size and shape, the cellular cuticle of the pileus, and the scurfy
stipe. However, the type is so poorly preserved as to render comparisons
with other collections practically useless as far as macroscopic features
are concerned. Singer (1947) commented on the blue-staining variant of
subglabripes to the effect that it had a more subviscid pileus and a
redder stipe. Kauffman's description of the type of B. scabroides emphasizes that the stipe was stained with red within and without and that the
scurfiness was reddish also. Smith's study of the type supports Singer's
statement in regard to the slight viscidity since the epithelial cells were
clearly subgelatinous (with a "halo") in KOH. In view of these factors
we propose that on the basis of the holotype, B. scabroides be reduced
to synonymy under B. subglabripes. It is possible that this variant deserves rank as a variety, but Singer who studied it fresh did not think
so, and we have not seen it fresh.