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

BOLETUS

319

171. Boletus hortonii, nom. nov.
Boletus subglabripes var. corrugis Peck, Bull. N. Y. State Mus. 2(8):112. 1889.
Pileus 4-12 cm broad, obtusely umbonate becoming convex, surface dry and under a lens pubescent, uneven to corrugated or alveolate,
colors as in B. subglabripes or merely dingy ochraceous with a reddish undertone, drying brownish with a slight Isabella color overtone.
Context yellow, when cut very slowly and weakly staining bluish in
some collections. Tubes about 8 mm deep, yellow, when.cut slowly and
weakly staining bluish; pores yellow and very minute, slowly bluish
when bruised in some collections. Stipe 6-10 cm long, 10-20 mm thick,
smooth, narrowly clavate, solid, yellow within; surface pale yellow,
naked to faintly pruinose, around the clavate portion slightly lateritious,
not rooting.
Spores 12-15 X 3.5-4.5 p,, smooth, narrowly inequilateral in profile, almost navicular in face view, yellow in KOH, yellow to pale tawny
in Melzer's, wall less than 0.5 gt thick.
Basidia 4-spored, 26-30 X 7-11 g when sporulating, yellow in
KOH or in Melzer's. Pleurocystidia rare to scattered, 32-45 X 7-12 u,
fusoid-ventricose, apex obtuse, smooth, thin-walled. Cheilocystidia
basidiole-like to fusoid-ventricose, 24-36 X 5-10 i, yellowish hyaline in
KOH.
Pileus cuticle a tangled trichodermium, the hyphae with the 2-4
cells back from the apical cell variously inflated (some up to 20 A wide),
the apical cell long or short but essentially tubular and 6-10, wide, up
to 100,i long, at times with secondary septa, slightly narrowed to apex,
smooth, thin-walled, yellowish hyaline in KOH, content merely yellowish in Melzer's. Clamp connections none.
Habit, habitat, and distribution.-Solitary in moist hardwoods, Ann
Arbor, Hoseney 1301. The Michigan collection consisted of young
material.
Observations.-Peck's type has been studied and the long tubular
extensions were found on the terminal inflated cells of the trichodermial
elements; the spores were as given above. Singer's (1947, p. 116) comments on this variety should be disregarded. Smith studied Peck's type
of variety corrugis and found the features as given in the above description.
Singer commented on the type being lost, but Stanley Smith located it
for A. H. Smith, who then made his study of it. Obviously, Singer did
not see the type and his comment: "However, the original description of
Peck's is all but convincing," is not relevant to the problem. The spore