North American species of Mycena.

104 NORTH AMERICAN SPECIES OF MYCENA

narrow to broad, pale rose at first, faces usually soon becoming
whitish, the edges fading or remaining pale rose; stipe 2-4 cm. long,
filiform or up to 0.5 mm. thick, toughish and flaccid, glabrous, concolorous with the pileus at first, becoming paler and hyaline, finally
grayish brown, attached to fern debris by a thin mat or by groups of
radiating white hairs, not readily separable from the tissue of the
pileus.
Spores 8-10 (11) X 4-4.5 Mu, narrowly ellipsoid to subcylindric,
amyloid; basidia four-spored; pleurocystidia rare to scattered (sometimes apparently absent), similar to the cheilocystidia; cheilocystidia
20-32 X 9-14 A, broadly ellipsoid or clavate to subglobose, apex
studded with short rodlike projections, contents hyaline or pale
pinkish; gill trama of enlarged cells, subhymenium very narrow and
indistinct, all portions pale vinaceous red in iodine; pileus trama with
a surface layer of broad hyphae (6-12 Az), the exposed surfaces of
which are strongly echinulate, the tramal body made up of greatly
enlarged cells (15-40 A), subhymenium very thin, all parts vinaceous
red in iodine; stipe vinaceous red in iodine, the surface cells covered
with echinulations similar to those on the pileus.
Habit, habitat, and distribution.-Scattered to gregarious on decaying fern fronds; New York, Michigan, Washington, and Oregon
in the United States and in Ontario in Canada. This species appears
to be rare though very widely distributed, but on Mt. Baker, Washington, near Martin Lake, it was collected in great abundance. It is
usually found during the late summer or fall.
Material studied.-Smith, 4476, 16573, 16746. Kauffman, Kentucky. Mains, 33-889, 34-49, 34-141, September 14, 1936, Michigan.
Observations.-The habitat and beautiful bright-rose color of the
carpophores are the outstanding features of this species. The manner
in which the gills fade is interesting but may cause some confusion
to the taxonomist. At times both the faces and the edges become
pallid, but sometimes the color persists in the edges, thus placing the
fungus in the old Friesian section Calodontes if no other characters
are considered. In this species the colored gill edge should not be
considered an important diagnostic character. The pigment appears
to be quite unstable.
From a study of tangential sections of the pileus it is evident
that the trama has been reduced to a well-developed hypoderm and
an almost nonexistent subhymenium. M. pterigena appears to be
closely related to M. juncicola. The two are similar in habit, size,