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

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THE BOLETES OF MICHIGAN

Tube trama of more or less parallel hyphae diverging to subhymenium,
hyaline to yellow in KOH and in Melzer's often with amyloid septa,subhymenium indistinct. Pileus trichodermium of hyphae with dull yellowbrown incrustations as seen in KOH mounts, the end-cells tubular to
cystidioid and also with incrustations, the subcutis and context hyaline in
KOH; in Melzer's the hyphae of the trichodermium incrusted and the
hyphal walls mostly amyloid (the layer blackish in sections mounted in
Melzer's), the hyphae 6-11 it or more wide and the cell often somewhat
enlarged but sphaerocysts not seen. Hyphae of the subcutis and context
with pale to dark orange-brown content in Melzer's and the septa showing
as amyloid rings (with a hole in the middle). Clamp connections absent.
Habit, habitat, and distribution.-Solitary to gregarious in the
virgin conifer forests of the Pacific Northwest, where it is common from
late August to October. In Michigan it is rare-it has been reported but
as yet we have not located a correctly identified specimen.
Observations.-This species is one of the most easily identified of
all boletes if one has a microscope and Melzer's reagent. We have noted
in many boletes that the septa of the hyphae in the tube trama were
more refractive than the side walls, but this is one of the few species
that we know in which the septa are violet in iodine and hence stand
out prominently in Melzer's mounts. Miller and Watling (1968) have
recently discussed this reaction. In addition to amyloid septa, the
trichodermial elements are heavily incrusted and amyloid. The color
of the stipe varies a great deal from brilliant red over a large portion to no red at all, and in the Pacific Northwest there is a second
species which regularly shows no red at all, B. coniferarum Dick & Snell.
The basidiocarps develop slowly in the cool mountain climate, and the
pattern of checking of the pileus surface varies accordingly. In Idaho
one finds mostly coarsely areolate basidiocarps, but in the fall in the
Cascades they occur frequently with the cuticle unbroken. The reticulum is usually pallid and one may have to look carefully to see it, but a
few specimens with red reticulum have been encountered-all of them old.
173. Boletus inedulis (Murrill) Murrill
Mycologia 30:523. 1938
Ceriomyces inedulis Murrill, Mycologia 30:523. 1938.
Illus. Pls. 128-29.
Pileus 4-11 cm broad, convex expanding to broadly convex or
nearly plane; surface dry, densely cottony tomentose at first, the layer