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

202

THE BOLETES OF MICHIGAN

Tubes 1-2 cm deep, depressed around the stipe, pallid becoming
wood-brown; pores grayish pallid staining dingy yellow-brown and in age
the stains dark cinnamon-brown.
Stipe 9-14 cm long, 1-2 cm thick at apex, equal or nearly so, solid,
staining as in pileus, merely dull brown around larval tunnels; surface
pallid or at base yellowish where decay had started; ornamentation fine,
sparse, pallid until late maturity, slowly becoming gray or slightly
darker, apex remaining pallid and pruinose.
Spores 15-18 X 5-6 it, smooth, with a minute apical thin spot, in
face view fusoid, in profile somewhat inequilateral, color in KOH dingy
ochraceous-tawny, slightly darker in Melzer's, wall about 0.3 i thick.
Basidia 4-spored, about 30 X 9 p, clavate hyaline in KOH and
yellowish in Melzer's. Pleurocystidia not found. Cheilocystidia clavate to
subfusoid or fusoid-ventricose, 26-42 X 8-12 iu, neck narrow and short,
apex subacute, content ochraceous in KOH, walls thin and smooth.
Caulocystidia fusoid to fusoid-ventricose, 36-62 X 8-11 Mi, walls thin and
smooth, content mostly hyaline in KOH. Caulobasidia with dingy ochraceous content.
Tube trama of somewhat divergent hyphae, the latter tubular and
with refractive cross walls, hyaline in KOH and not obviously gelatinous,
laticiferous elements rare. Pileus cutis of appressed narrow (4-8 ji), tubular hyphae with yellow-brown content in KOH and Melzer's, not
rounding into globules in Melzer's, end-cells tubular to narrowly clavate
or weakly cystidioid. Hyphae of subcutis and adjacent context yellow in
Melzer's. Clamp connections absent.
Habit, habitat, and distribution.-Gregarious under birch and aspen,
Brimley, Chippewa County, July 13, 1968, H. D. Thiers and W. Patrick
(Smith 75572).
Observations.-This species is worth placing on record since it is the
only one known to us with predominantly hyaline caulocystidia but
with the other elements of the caulohymenium colored. The vinaceousbrown stains of the cut flesh, fine ornamentation of the stipe, and the
narrow cuticular hyphae are also distinctive.
102. Leccinum scabrum (Fries) S. F. Gray
Nat. Arr. Brit. Pls. 1:647. 1821.
f. scabrum
Illus. P1. 88.
Pileus 4-10 cm broad, pulvinate to broadly convex, margin even
and scarcely projecting beyond the tubes, moist to dry or when wet