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

LECCINUM

215

"tawny-olive"), in age often olivaceous or pea-green at least in patches.
Context very thick and soft, pallid but gradually avellaneous when cut.
Tubes 10-20 mm deep, free or nearly so at maturity, pallid, slowly
becoming wood-brown but when bruised staining purplish brown; pores
pallid-avellaneous but staining greenish when bruised, the stains often
slowly becoming dingy yellowish.
Stipe 4-12 cm long, 8-15 mm thick, pallid to avellaneous and
densely furfuraceous to scabrous, the ornamentation avellaneous to
wood-brown, base of stipe with white appressed mycelium which frequently is stained greenish, solid, pallid within but slowly staining gray
when sectioned, drying whitish over the cut surfaces.
Spore deposit near cinnamon-brown; spores 11-15 X 4.5-6 u,
smooth, fusiform to subfusiform in face view, in profile inequilateral,
the suprahilar depression broad and shallow to very distinct, ochraceous
to dingy ochraceous in KOH, in Melzer's mostly ochraceous but many
very dark rusty brown, wall slightly thickened.
Basidia 4-spored, 26-32 X 9-12/, hyaline in KOH, yellowish in
Melzer's. Pleurocystidia 30-42 X 9-14 u, fusoid to fusoid-ventricose,
with obtuse apex, thin-walled, smooth, content hyaline in KOH and
Melzer's. Pileus trichodermium with elements having the upper 24 cells
inflated to nearly isodiametric and enlarged to 15-35 u, in older stages
the layer appearing pseudoparenchymatous; with a dull brown cellular
content when fresh in water mounts, nearly hyaline as revived in KOH
or Melzer's. Clamp connections absent.
Habit, habitat, and distribution.-Gregarious to scattered in oldgrowth stands of hardwoods, southeastern part -of the state during late
summer and early fall after heavy rains. Under the right conditions it is
abundant.
Observations.-This is basically a glabrous species tending to become
rugose-reticulate, but it becomes very conspicuously areolate in age or
on drying, a feature not present in anything like the same degree in
other species of this group. No pseudocystidia were found. It differs
from L. carpini in the flesh not distinctly turning vinaceous when basidiocarps are sectioned and in the tubes showing no yellow flush when
young.
Subsection LUTEOSCABRA
For the diagnostic features see key to subsections.
Type species: Same as for the section.