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

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THE BOLETES OF MICHIGAN

84. Leccinum proliferum Smith, Thiers, & Watling
Mich. Bot. 6:127. 1967
Pileus 4-6 cm broad, convex becoming broadly convex; surface
dry to subviscid, white, spotted with minute brownish appressed squamules, margin even and sterile for about 0.25 mm. Context white, when
cut slowly grayish near stipe apex.
Tubes depressed around the stipe, pallid becoming wood-brown
and when dried dark yellowish brown.
Stipe 4-6 cm long, 8-11 mm at apex, 12-18 mm at base, pallid,
overlaid with dull brown ornamentation which blackens on drying, solid,
white within, slowly grayish when cut but with no initial reddish state,
lacking yellow stains as dried.
Spores 18-26 X 6-7.5 u, smooth, fusoid in face view, inequilateral
in profile view, pale cinnamon and dark cinnamon singly and in groups
respectively in KOH, becoming reddish cinnamon in Melzer's, wall
thickened slightly, apical spot distinct but not a true pore.
Basidia 4-spored, 18-28 X 10-14 i', yellow in Melzer's, readily gelatinizing in KOH, lacking a large globule when revived in KOH. Pleurocystidia rare, mostly near tube mouths, 35-45 X 8-11 u, hyaline in
KOH. Cheilocystidia 18-50 X 4-11 u (long and narrow), fusoid-ventricose with acute apex, yellow to hyaline in KOH. Caulocystidia dull
ochraceous in KOH, clavate-mucronate to fusoid-ventricose but neck
hyphal-like (some branched once or twice), ventricose part 25-40 X
8-15 JI, neck finally up to 200,u long and 4-6 p wide, some filamentous
elements present in fascicles over lower half of stipe in addition.
Pileus trichodermium with the elements soon becoming appressed,
tubular, 4-10,L wide, the cells moderately long, walls smooth to inconspicuously roughened, with ochraceous content in KOH and hardly
changing in Melzer's, end-cells tubular to slightly enlarged. Hyphae of
subcutis 3-5, wide, gelatinous, orange to bright ochraceous in Melzer's.
Hyphae of context not as bright as the subcuticular hyphae in Melzer's.
Clamp connections absent.
Habit, habitat, and distribution.-In a swamp under large-toothed
aspen, St. Ignace, Mackinac County, early July, not common.
Observations.-This species is similar in some respects to L. snellii,
but the difference in shape of the cells in the elements of the pileus
cutis distinguishes the two readily, to say nothing of the overall coloration.