North American species of Mycena.

EUMYCENA: TYPICAE

333

equal, hollow, fragile to cartilaginous, pruinose above when young
and the lower portion covered with small white fibrillose flecks, soon
naked and glabrous, polished and translucent in age, base whitestrigose and somewhat rooting, concolorous with the pileus over all
or paler gray.
Spores (8) 9-11 X 5-7 u, broadly ellipsoid, smooth, amyloid;
basidia four-spored, 30-35 (40) X 6-8 u; pleurocystidia scattered to
rare and soon collapsing, similar to the cheilocystidia but usually
remaining unbranched; cheilocystidia clavate to mucronate, in age
developing obtuse fingerlike projections over the apex (1-6), sometimes merely remaining saccate, 35-52 X 9-18,, hyaline; gill trama
dark vinaceous brown in iodine, made up of short and moderately
broad regularly arranged cells; pileus trama with a thin pellicle, a
well-differentiated hypoderm, and a thick tramal body of filamentous
hyphae, all but the pellicle vinaceous brown in iodine.
Habit, habitat, and distribution.-Gregarious to subcespitose on
wood of either hardwood or conifer trees; New York, Pennsylvania,
Michigan, Colorado, Wyoming, Idaho, Washington, and Oregon in
the United States and Ontario in Canada. It fruits from July to
November, but is rather sporadic. During some seasons it is common.
Material studied.-Smith, 32-326, 32-544, 33-1124, 33-1125, 1174,
4671, 5065, 5188, 5260, 6164, 8101, 8216, 9283, 11109, 13590, 15502,
15504, 15532, 18144, 18217, October 26, 1937, Oregon; November 18,
1931, Michigan; June 15, 1933; October 8, 1940. Flett, Washington.
Gruber, Idaho. Kauffman, four collections, Colorado; three collections, Michigan; one collection, Wyoming. Mains 5182, 5259.
Overholts, 1361, 17596. Stuntz, F 465.
Observations.-The pleurocystidia are often difficult to find in
mature or old specimens but can usually be demonstrated in young
pilei. They collapse very readily and are hard to revive in KOH.
As seen in young pilei, they are usually devoid of the fingerlike prolongations characteristic of the cheilocystidia, but there is a tendency
to produce them. If one happens to get a pileus in just the right
stage of development, they can readily be observed.
The colors of the entire fungus are blackish gray at first and become watery gray before fading to pale ashy gray. The generally
even coloration, along with the fragile consistency, is characteristic
among the lignicolous cespitose Mycenae and distinguishes this
species from all except M. alnicola, from which it is separated by the
larger spores.