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

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THE BOLETES OF MICHIGAN

Spores 8-9 (10) X 4-4.5 (5) g, smooth, wall thin, no apical differentiation, in face view suboblong or narrowed slightly to distal end, in
profile obscurely inequilateral, suprahilar depression typically shallow;
color in KOH weakly yellow, in Melzer's merely tinged fulvous; no
fleeting-amyloid reaction present on revived material.
Basidia 18-22 X 6-7 J,, 4-spored, hyaline. Pleurocystidia scattered,
38-52 X 10-14., subfusoid, apex subacute, thin-walled, content when
revived in Melzer's or KOH yellow, often originating from broad yellow
laticiferous hyphae. Caulocystidia in patches near apex, 16-22 X 8-11.u,
short-clavate, hyaline in KOH, thin-walled, content "empty."
Cuticle of pileus a collapsing trichodermium the hyphae tubular
and 4-6 gu wide, in a gelatinous matrix, hyaline or nearly so (in Melzer's
or KOH), apical cells tubular with blunt apex. Context hyphae next to
cuticle not colored in Melzer's. Clamp connections none.
Habit, habitat, and distribution.-On a hillside among grasses under
oak, Ann Arbor, August 14, 1915, C. H. Kauffman.
Observations.-Kauffman had tentatively regarded this as a smallspored B. badius. In many respects-especially spore characters-it is
similar to Suillus castanellus but has a differently colored hymenophore
with the pores staining blue slightly when bruised. The colors are more
ferruginous than in B. badius, and the very small spores at once distinguish it from the variants of that species. It is named in honor of C. H.
Kauffman, the collector.
161. Boletus pallidus Frost
Bull. Buff. Soc. Nat. Sci. 2:105. 1874
Suillus pallidus (Frost) Kuntze, Rev. Gen. P1. 3(2):536. 1898.
Ceriomyces pallidus (Frost) Murrill, Mycologia 1:152. 1909.
Illus. Pls. 116-17 (above).
Pileus 4.5-15 cm broad, hemispheric to convex young, becoming
broadly convex to nearly plane to slightly depressed, surface dry and
unpolished, smooth but in age often strongly areolate, glabrous to obscurely tomentose to subtomentose, tacky in age when wet, pallid to
cinereous to "pale pinkish buff' or near avellaneous, finally dingy
leather-brown, occasionally with faint rose tints, margin sterile and often
crenated. Context up to 2.5 cm thick, soft, nearly white or near the
tubes pale yellow, often with a trace of pink where bruised, when young
and firm with a slight tendency to turn blue when injured; taste mild to