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

BOLETINELL US

395

radiating ridges present with crossveins dividing off areas which in turn
are further divided into shallower pores.
Stipe 2-4 cm long, 5-10 (25) mm thick, slightly eccentric to eccentric to lateral, expanded upward, base firmly attached, solid, flesh
concolorous with that of the pileus, surface concolorous with pileus
below and with tubes above, staining reddish brown when injured, base
often blackish.
Spore deposit olive-brown ("Isabella color" to "tawny-olive"),
spores 7-10 X 6-7.5 u, in optical section ovate to elliptic varying toward
subglobose, smooth, in KOH hyaline to pale olive-ochraceous or pale
yellow-brown, in Melzer's yellowish brown to distinctly rusty brown
(dextrinoid), smooth, no apical pore present, wall slightly thickened.
Basidia 4-spored, 30-36 X 10-12,, hyaline to yellow in KOH,
darker yellow in Melzer's. Pleurocystidia 20-35 X 6-9 p, fusoid-ventricose. Cheilocystidia absent to rare, smooth, thin-walled, hyaline, fusoidventricose to rostrate.
Tube trama divergent from a central strand but becoming parallel
or nearly so, gelatinous, hyaline in KOH, nonamyloid. Pileus cuticle
apparently differentiated from the tramal body as a more compactly
interwoven layer, yellow in KOH, pigment diffusing from the hyphae,
both cutis and tramal body nonamyloid but in Melzer's incrusting pigment is found on some hyphae of the cuticle and the layer is dark
yellow-brown. Clamp connections present.
Habit, habitat, and distribution.-Scattered on moist ground, usually under species of Fraxinus in Michigan, late summer and early fall,
common in the Lower Peninsula.
Observations.-Sections revived in Melzer's give a "fleeting-amyloid" reaction but none of the hyphae or the spores are truly amyloid.
Granular material present in the mounts is violaceous-fuscous both in
KOH and Melzer's and hence is not amyloid.
The variant described is var. opacus Peck, the type variety being
viscid, but we believe this is merely a stage in the development of the
basidiocarps much as in many other boletes.
Material examined. -Berrien: Smith 51215, 51227. Clare: Boynton
8-2949. Chippewa: Povah 84-19. Gratiot: Potter 3450, 3784, 3953,
5840, 6218, 6266, 7529, 7609, 7715, 8376, 8737, 9724, 11942, 12479,
12643. Jackson: Mazzer 4124, 4284. Midland: Smith 67790. Oakland:
Mazzer 4428; Smith 7621. St. Clair: Boynton 1949, 7-1049.
Washtenaw: Baxter 7-21-20, 7-2120a; Homola 1202; Hoseney 109, 148,
577, 659; Smith 4985, 15245, 62573, 66418, 72830; Thiers 4571.