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

140

THE BOLETES OF MICHIGAN

Stipe massive, 8-12 (16) cm long, 1-3 cm at apex, clavate, solid,
pallid within and when cut staining reddish and then black; surface
covered by coarse black fibrils often in zones giving a scaly rather than
punctate effect, pallid beneath the scales.
Spore deposit near "bister" as dried (a dingy yellow-brown);
spores 12-15 X 3.5-4.5,, smooth, apex lacking a pore or thin spot,
shape in face view fusiform, in profile somewhat inequilateral, yellowish
hyaline to dingy ochraceous in KOH, in Melzer's slightly browner, wall
about 0.2 p thick.
Basidia 4-spored, clavate, hyaline in KOH. Pleurocystidia scattered,
clavate-rostrate, neck narrow and abruptly set off from the ventricose
part, apex subacute, thin-walled, content ochraceous in KOH or hyaline.
Cheilocystidia 23-37 X 7-12 p, fusoid-ventricose, apex subacute to
obtuse, content hyaline to yellowish as revived in KOH. Caulocystidia
clavate, elliptic-pedicellate, mucronate or fusoid-ventricose, 35-70 X
10-25 u, content dingy ochraceous in KOH, wall thin and apex often
remaining collapsed, subiculum hyphae often colored like the cystidia,
caulobasidioles and basidia also dingy ochraceous in KOH.
Tube trama typical for the genus; laticiferous hyphae rare, their
content ochraceous in KOH and Melzer's and not standing out prominently in the mount. Pileus cutis of appressed hyphae 4-8 (10)/ wide,
mostly tubular or nearly so, content weakly ochraceous in KOH but in
Melzer's many with a rusty red homogeneous content and the others
with yellow to orange homogeneous content, walls mostly smooth,
apical cell tubular to somewhat cystidioid. Hyphae of subcutis and
adjacent context yellow to ochraceous-orange in Melzer's. Clamp connections none.
Habit, habitat, and distribution.-Gregarious under aspens, Pellston,
Emmet County, August 15, 1968, collected by W. Patrick (Smith 76025).
Observations.-Although obviously related to L. atrostipitatum,
this species is at once distinguished by the duller color, more fibrillose
appearance of the stipe ornamentation, and by the green FeSO4 reaction. The colors are much duller than in L. testaceoscabrum. Oak is
excluded as a tree-associate, and the cuticular hyphae of the pileus are
narrower. At maturity it most closely resembles L. insolens in color.
66. Leccinum testaceoscabrum (Secretan) Singer
Amer. Midl. Nat. 37:123. 1947
Boletus testaceus scaber Secretan, Mycogr. Suisse 3:8. 1833.
Boletus rufescens scaber Secretan, Mycogr. Suisse 3:11. 1833.
(B. rufescens Konrad, Bull. Mens. Soc. Linn. Lyon p. 10. 1932.)