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

SUILL US

51

Material examined.-Cheboygan: Smith 37856, 57483, 57892,
62947, 62979, 63340, 64042, 7-31-62; Thiers 3456, 3784, 3867, 4340.
Chippewa: Smith 72836. Crawford: Smith 57498. Emmet: Thiers 3243,
3736. Luce: Smith 36952, 44115. Marquette: Bartelli 296.
13. Suillus luteus (Fries) S. F. Gray
Nat. Arr. Brit. P1. 1:646. 1821
Boletus luteus Fries, Syst. Mycol. 1:385. 1821.
Cricunopus luteus (Fries) Karst. Rev. Mycol. 3:16. 1881.
Viscipellis luteus (Fries) Quelet, Enchir. Fung. p. 155. 1886.
Ixocomus luteus (Fries) Quelet, Fl. Mycol. Fr. p. 414. 1888.
Illus. PI. 17.
Pileus 5-12 cm broad, hemispheric to obtuse at first, broadly convex to plane in age; surface glabrous and viscid but at times somewhat
streaked beneath the slime, color dark reddish brown to dark yellowbrown, fading out to more or less ochraceous in age. Context white or
tinted more or less pale yellow especially near the tubes and stipe apex;
odor not distinctive, taste mild.
Tubes 3-7 mm deep, gradually shorter toward the pileus margin,
adnate to subdecurrent, at first whitish to pale yellow, at length yellow
to olive-yellow ("old gold" to "honey-yellow"), unchanging when cut;
pores 3 per mm, in age 1-2 per mm, surface with a sheen and mouths
yellow at first but becoming dark-dotted as clusters of cheilocystidia
darken.
Stipe (3) 4-8 cm long, 1-2.5 cm thick, equal or attenuate at base,
typically peronate by the whitish veil up to the membranous often
reflexed rather persistent annulus which is purplish drab in a zone on
the outer (or under) side and this material becoming gelatinous under
conditions of high humidity; glandular dotted above and below the
annulus, solid, white within at first, yellow in age.
Spore deposit dull cinnamon moist, pale cinnamon faded (airdried); spores 7-9 X 2.5-3 pu, smooth, with a pronounced hyaline sheath,
more or less oblong in face view, narrowly inequilateral in profile view,
nearly hyaline in KOH, merely yellowish in Melzer's.
Basidia 4-spored, 14-18 X 4-5 JI, yellowish in Melzer's and in
KOH. Pleurocystidia in scattered to rare bundles surrounded by bister
incrusting material when revived in KOH (details of the bundle obscured
by the covering of debris), when isolated the individual cystidia 20-35 X
5-7 J and narrowly clavate, content usually bister as revived in KOH.
Cheilocystidia similar, but tube edges often a mass of bister incrustation