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

42

THE BOLETES OF MICHIGAN

8. Suillus grevillei (Klotzch) Singer
Farlowia 2:259. 1945
Boletus grevillei Klotzch, Linnaea 7:198. 1832.
Boletus elegans Fries, Epicr. Syst. Mycol. pp. 409-10. 1838.
Boletus clintonianus Peck, Ann. Rept. N. Y. Cab. 23:128. 1872.
Suillus grevillei var. clintonianus (Peck) Singer, Agaricales in Mod. Tax. p. 721.
1962.
Illus. PI. 12.
Pileus 5-15 cm broad, hemispheric becoming broadly convex to
nearly plane; surface glabrous, glutinous, "chestnut" on the disc, "empire-yellow" on the margin, at times finally bright yellow overall, pellicle
separable, margin sterile. Context "straw-yellow" to "amber-yellow,"
soon rubescent ("salmon-buff' or "flesh color") on injury, rather thick
(1-1.5 cm); taste mild to slightly astringent to bitterish, odor none to
somewhat metallic.
Tubes adnate to depressed, becoming subdecurrent, 10-15 mm
deep, "amber-yellow" (sulphur-yellow) but finally "olive-ocher" (oliveyellow), when bruised or cut becoming testaceous to vinaceous-brown;
pores angular, 1-2 per mm, dissepiments rather thick and entire.
Stipe 4-10 cm long, 1-3 cm thick, equal to slightly clavate, solid,
flavous to pale yellow within and over exterior, sometimes slightly
sulphur greenish in base when cut but not truly green, surface soon
developing chestnut variegations; annulate with a typically floccose
annulus which may have a gelatinous outer layer in wet weather, distinctly reticulate above the annulus from extensions of the decurrent
tubes, dingy in age, staining vinaceous-brown after handling.
Spore deposit olive-brown moist, "Sayal-brown" (dull cinnamon)
air dried; spores 8-10 X 2.8-3.5,, more or less oblong in face view and
obscurely inequilateral in profile view, smooth, with a faint hyaline
outer sheath, pale olivaceous to ochraceous in KOH and Melzer's.
Pleurocystidia numerous to scattered or rare, sometimes in fascicles,
40-60 X 6-8 u, subcylindric to clavate, but some obscurely fusoid-ventricose, bister incrusting material at base only, content brownish to yellowish in KOH and Melzer's. Cheilocystidia in fascicles, incrusted with bister
pigment at level of the hymenium, the fascicles scattered to numerous,
the individual cystidia similar to the pleurocystidia. Caulocystidia solitary or in scattered small fascicles and with incrusting pigment as revived
in KOH.
Tube trama gelatinous and of divergent hyphae. Pileus trichodermium soon collapsing, of long gelatinous hyphae 3-6,I in diameter, the cells