North American species of Mycena.

52 NORTH AMERICAN SPECIES OF MYCENA

A. H. Smith, n. 17390, prope Heart O'Hills, Mt. Angeles, Olympic
Mts., Wash., Sept. 29, 1941.
Pileus 1-3 (4) mm. broad, obtusely conic to convex, margin
straight at first, in age plane or the margin somewhat uplifted, glabrous, moist, unpolished, disc "Isabella color" (sordid yellowish
brown), paler and more buff-colored toward the margin ("cream
buff"), when moist conspicuously translucent-striate to the disc with
broad, dark striations, somewhat plicate when faded; flesh membranous, not fragile but not reviving when remoistened, odor and
taste not distinctive; lamellae adnate but soon seceding and adhering
to each other to form a collar around the stipe, distant, 7-9 reach
the stipe, lamellulae lacking or one tier present, moderately broad,
pallid (whitish in contrast to cap), edges even and not differently
colored; stipe 9-4 cm. long, more or less filiform, straight or flexuous,
seated on a "pale orange-yellow" flat strigose-hairy basal disc, glabrous and polished toward the apex, minutely pruinose toward the
basal disc, lower portion pale sordid yellow, pallid to whitish above.
Spores 8-9 (10) X 4-5 t, narrowly ellipsoid, smooth, amyloid,
basidia four- or occasionally two-spored; pleurocystidia not differentiated; cheilocystida abundant, 18-36 X 9-16 u, clavate to subcapitate, the enlarged portion verrucose, hyaline in water mounts of
fresh material; pileus trama very distinctive, the surface corticated
with a layer of cells similar to the cheilocystida or larger, the layer
beneath these (including their pedicels) gelatinous, central body of
the trama vesiculose, the subhymenium of short hyphae with rather
broad cells.
Habit, habitat, and distribution.-Singly or in groups of two or
more carpophores on dead leaves of Gaultheria shallon Pursh. The
species at present is known only from the type locality, but will more
than likely be found in Oregon and northern California as well.
Material studied.-Smith, 17390.
Observations.-The sordid yellowish-brown pileus, yellowish stipe,
and pale orange-yellow basal disc distinguish the fungus macroscopically. Microscopically the plant is very similar to M. Mucor
as described by Kiihner (1938), particularly in the organization of the
trama of the pileus. However, the degree of its organization in
M. Gaultheri appears to be higher than that of M. Mucor. The
former also differs from the latter in consistency. M. Gaultheri is
rather pliant and somewhat like M. corticola in this respect, whereas
the European species, at least as I know it, is very delicate.