The North American species of Psathyrella.

1972]

PSATHYRELLA

151

ochraceous in KOH, a few vesiculose cells also present. Caulocystidia only a
few clavate cells observed as such.
Pileus cuticle a layer of vesiculose cells 12-40, wide, the walls 0.5-1 n thick
(the double lines 2 K thick), colored tawny in HO when fresh and distinctly
ochraceous revived in KOH (more highly colored than the hyphae of the context),
their content not distinctive. Hyphae of the subcuticular region pale ochraceous
in KOH, walls smooth or rarely in the area just beneath the cuticle with the
wall slightly roughened. Clamp connections present. In Melzer's the cuticular
cells more ochraceous than the hyphae of the context and with local weakly
dextrinoid wall thickenings evident. In sections the cuticular layer darker than
the context to the naked eye.
Type locality. Near Hulbert, Michigan.
Habit and habitat. Cespitose on or around stumps of Tsuga (hemlock).
Distribution. Known only from the type locality.
Observations. This is one of the most easily recognized species in the genus
by virtue of the cuticular and tramal features described above, the nine-pinshaped cystidia and the small spores tending to be wedge-shaped in face view.
The basidiocarps are typically large as was evidenced by clusters too old to
preserve.
106. Psathyrella subalpina A. H. Smith & Stuntz, Mycologia 42: 130. 1950.
Illust. 1. c., fig. 20 (f, g, h, j). Text Figs. 264-266.
Pileus 2-4 cm broad, (probably larger when fully mature), buttons obtuse and
expanding to convex or plane, occasionally with a broad low umbo, surface at
first hoary to near disc from a thin coating of veil fibrils, glabrescent over all
except the incurved margin which retains a zone of avellaneous fibrils, surface
moist and hygrophanous, "russet" (dark rusty brown) at first but shading to
cinnamon in fading. Context thick, watery cinnamon-brown, taste none, odor
imperceptible or very faint and reminding one of cinnamon.
Lamellae close, adnate, narrow to moderately broad, near avellaneous in
buttons changing through wood brown to a dark purplish cinnamon-brown when
mature, edges even.
Stipe (2-)3-6 cm long, (3-)4-6 mm thick, somewhat enlarged downward and
with a mycelioid base sunken in the soil, surface pallid-fibrillose from the pale
avellaneous veil, pallid and pruinose near the apex, hollow, brownish within
and cinnamon-brown in the base, lower half glabrescent, in old carpophores
darkening from the base upward.
Spores 6-8x4-4.5 x4.5-5.5 A, slightly compressed, smooth, apical pore distinct (under oil) but inconspicuous and apex not truncate, shape in face view
broadly elliptic to obscurely rectangular (base somewhat truncate), in profile
subelliptic to somewhat bean-shaped, color in KOH dark bister but soon clouded
chocolate-gray, in Melzer's tawny, wall about 0.3,u thick.
Basidia 23-34 x 6-9 p, elongate-clavate, hyaline in KOH individually but
sections of the hymenium with an ochraceous tone when first revived in KOH.
Pleurocystidia abundant, 34-56 x 8-14 A, ventricose, neck becoming elongated and
apex subacute to oval (not truly capitate), wall thin, smooth and hyaline in
KOH, content not distinctive in either KOH or Melzer's. Cheilocystidia of two
types, the first similar to but usually smaller than the pleurocystidia and the
second clavate to subsaccate and 12-18x 7-15 /, thin-walled to pale ochraceous
in KOH. Caulocystidia not located, but hyphae of the veil often ending in clavate