North American species of Mycena.

360 NORTH AMERICAN SPECIES OF MYCENA

disc, "drab" toward the whitish margin, fading to pale grayish brown
or yellowish brown at times, the margin always paler, usually conspicuously striate, sometimes widely plicate, often radially wrinkled;
flesh very thin, pliant, odor and taste not distinctive or merely slightly
farinaceous; lamellae horizontally adnate or arcuate-decurrent, narrow to moderately broad, subdistant, 9-19 reach the stipe, two tiers
of lamellulae, pallid to grayish, intervenose, edges even and pallid;
stipe 1-3 (6) cm. long, filiform or up to 1 mm. thick, equal, flexuous,
cartilaginous and firm, tubular, the apex pallid or at times yellowish
to greenish yellow, pallid grayish below or in age yellowish over all,
base usually crooked and conspicuously white-strigose.
Spores 7.5-9 (10) X 4-5.5 ji, subovoid, often with A prominent
curved apiculus, nonamyloid; basidia two- or four-spored; pleurocystidia not differentiated; cheilocystidia abundant, resembling sterile
basidia when young but becoming elongated, (23) 26-38 X 5-8 A,
subcylindric in age and somewhat irregular in outline, hyaline; gill
trama of interwoven hyphae, sordid yellowish in iodine; pileus trama
with a thin, often poorly differentiated pellicle, a distinct hypoderm,
and the remainder of interwoven filamentous hyphae, yellowish in
iodine.
Habit, habitat, and distribution.-Single to scattered on pieces of
bark or on sticks usually partly buried in the mud or soil in wet places;
not common, usually found during late spring and early summer but
also fruiting in the fall; Michigan and Washington.
Material studied.-Smith, 32-21, 32-79, 32-453, 33-132, 1354,
3284,4459,8322,13446,13876,14078, 14128, 15227.
Observations.-Previously (Smith, 1934) this fungus has been
referred to Omphalia. In view of the broader scope given to the
genus Mycena by Kiihner, with which I am in agreement, this species
is properly classified as a Mycena. Like many of these small, inconspicuous agarics, M. speirea is readily recognizable once one has
become familiar with it, but is not always easy to identify the first time
it is collected. The yellow color in the apex of the stipe is a fairly
reliable character, but young specimens must be observed. All stages
from pallid to grayish yellow, bright yellow, and greenish yellow have
been found near Ann Arbor. In age the stipe may become sordid
yellow over all, but that is a discoloration. The cheilocystidia often
appear to be undifferentiated on maturing pilei, but are readily distinguishable on caps just past maturity. M. speirea is nearly always
found along with M. acicula, and this should serve as a clue to its
identity.