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

SUILL US

41

KOH on cuticle quickly olive, on context bluish gray; with FeS04 bluegray on context and cuticle.
Tubes 5-6 mm deep, decurrent, dingy yellowish, soon dingy to
dull pale cinnamon where cut; pores small but in age up to 1 mm broad,
staining pale cinnamon brownish where bruised.
Stipe 8-9 cm long, 10-15 mm thick at apex, equal or nearly so,
solid, yellow within at apex, dingy rusty brown below and turning green
when cut in lower or midportion or throughout; surface at apex canaryyellow, vinaceous-cinnamon lower down, apex striate to subreticulate
with decurrent lines from tubes, not glandular dotted; annulus superior,
often with a gelatinous margin, remainder floccose and yellow.
Spore deposit "chestnut-brown" to "cinnamon-brown," moist but
fading to pale cinnamon-brown as it air dries, finally becoming clay
color; spores 7-10 X 4-4.5 g, suboblong to obscurely inequilateral in
profile, in face view narrowly elliptic to subcylindric, smooth, dingy pale
ochraceous-brown in KOH, slightly paler in Melzer's.
Basidia 25-32 X 7-9 p, pale dingy ochraceous in KOH (in the
hymenium), about the same color in Melzer's, 4-spored; sterigmata very
fine. Pleurocystidia in bundles or isolated, 35-60 X 6-8 A, hyaline to
bister revived in KOH, with incrusting bister pigment surrounding the
base of the cluster, thin-walled. Cheilocystidia similar to pleurocystidia
and very numerous, with more colored ones and more incrusting pigment in and around the bundles.
Tube trama of slightly divergent gelatinous hyphae 4-8 g in diameter (sections revived in KOH), no incrusting pigments present, hyphae
thin-walled; subhymenium of interwoven hyphae appearing cellular in
sections from the cut ends, only subgelatinous in KOH.
Pileus cuticle a thick layer of interwoven gelatinous hyphae 3-7 A
in diameter (possibly a collapsed trichodermium), with thin walls yellowish in KOH, no incrusting pigment seen. Context of floccose nongelatinous interwoven hyphae 5-15 p in diameter, with the cells often somewhat inflated, no incrusting pigment seen. Clamp connections absent.
Habit, habitat, and distribution. -Gregarious in swamps with Larix
(larch) or often at the edge of such areas. To date it is known only
from Oakland County. Smith 66436, 67759, 67806, 75160, and the
type (Smith 64508).
Observations.-S. grevillei from the same locality had an olivebrown spore deposit. The difference in the color of the fresh spore
deposits was very striking at first but on air-drying they both became
about the same color. The green staining is the best field character for
the recognition of this species.