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

SUILL US

69

Tube trama bilateral and gelatinous but with conspicuous broad
(up to 15 j) laticifers with dark brown content as revived in KOH.
Epicutis of pileus a thick layer of appressed-interwoven hyphae 2.5-5 u
in diameter and hyaline in KOH, but many of the hyphae (or segments of
them) with a hyaline refractive content. Subcutis of floccose hyphae
with pigment pockets which become vinaceous in KOH, or the entire
region flushed vinaceous. Clamp connections absent.
Habit, habitat, and distribution.-Gregarious under 2-needle pines,
in plantations in the southern part of the state, late summer and fall.
Observations.-This variety consistently has a thinner stipe, paler
colors and more conspicuous laticiferous hyphae in the trama of the
hymenophore. Also, the tubes are more brilliant yellow. It may be desirable eventually to recognize this as an autonomous species.
Material examined.-Oakland: Smith 66452. Ogemaw: Smith
67486. Washtenaw: Smith 72555.
25. Suillus lactifluus (Wither. ex S. F. Gray) Smith & Thiers
Mich. Bot. 7:16. 1968
Leccinum lactifluum S. F. Gray, Nat. Arr. Brit. Pls. 1:647. 1821.
Illus. PI. 30.
Pileus 4-10 cm broad, obtuse to convex, expanding to plane; surface slimy, color pinkish buff to more or less pinkish cinnamon, in age
darker reddish cinnamon, glabrous, in age streaked to some extent beneath the slime or finally distinctly virgate; margin sterile and overhanging the edge as a thin membrane 0.5-1.5 mm wide (as in species of
Leccinum section Leccinum). Context watery pallid but with lemon-yellow areas especially near the tubes, dull lilac-blue with KOH, red in
NH40H, olive with FeS04, odor slight, taste acid.
Tubes pale yellow ("baryta-yellow"), when young and just forming, duller in color and usually beaded copiously with droplets of a
milk-like latex which evaporate by maturity, adnate to short decurrent
or in intermediate stages slightly depressed, up to 8 mm deep; pores
minute, 2-3 per mm at first but becoming 1-2 per mm at maturity,
staining brownish where bruised ("cinnamon-buff").
Stipe 2-5 cm long, evenly enlarged downward or in age narrowed
downward, virgate within with lemon-yellow streaks, staining cinnamon
to vinaceous-cinnamon in the base; surface pale lemon-yellow overall at
first, very inconspicuously punctate above but the ornamentation concolorous with remainder of the surface and not darkening by maturity