North American species of Mycena.

94 NORTH AMERICAN SPECIES OF MYCENA

Omphalopsis californiensis Murrill, ibid., p. 315.
Omphalia californiensis Murrill, Mycologia, 8: 220. 1916.
Illustrations:
Text fig. 7, no. 2 (p. 91).
Beardslee, Mycologia, 9, pl. 4, fig. 2 (as Omphalia gracillima).
Kauffman, Agar. Mich., 2, pl. 171, lower figs. (as Omphalia gracillima).
Pileus (2.5) 3-10 mm. broad, convex or with a small sharp papilla,
sometimes turbinate, the margin appressed against the stipe or connivent at first, surface moist, glabrous, translucent-striate, pure
white, opaque when faded and then becoming sulcate, appearing
minutely fibrillose under a lens when faded, flesh membranous and
fragile, no odor or taste; lamellae decurrent, often unequally decurrent in age, some developing a long tooth, broad (2 mm.), distant,
8-11 reach the stipe, one or occasionally two tiers of lamellulae, pure
white, edges even; stipe 2.5-4 cm. long, less than 1 mm. thick, equal,
fragile, solid, hyaline-white, faintly frosted at first, soon glabrous,
attached to fallen leaves by a flat mycelial disc so tightly that some
of the leaf adheres to the base of the stipe when specimens are collected.
Spores 7-9 X (3) 4-5 u, ellipsoid to narrowly ellipsoid, nonamyloid; basidia four-spored; pleurocystidia and cheilocystidia not
differentiated; gill trama homogeneous, composed of enlarged cells
(50-120 X 15-925 ), yellowish in iodine; pileus with a thin surface
pellicle from which arise numerous thin-walled filamentous simple or
branched hyphal projections, the trama of enlarged sausage-shaped
cells 50-200 X 15-25,u, yellowish in iodine.
Habit, habitat, and distribution.-Scattered to gregarious on bark
and fallen leaves of hardwoods during the late summer and autumn;
Tennessee, New York, Michigan, Washington, and California.
Material studied.-Smith, 1346, 1375, 1651, 3274, 4414, 6969,
9837, 15197, 18309, June 21, 1935, Michigan. Hesler, 14477. Kauffman, September 3, 1914.
Observations.-The spores of the type measure 7-9 (10) X 3.5-5 t,
and no differentiated cystidia were found. The fungus Kauffman
placed in this species had spores 8-10 X 2-4,u and must remain
doubtfully determined, since his specimens were lost and his measurements and comments on the spores do not check with the type. He
probably had a form of M. gracilis in which the gills were more decurrent than usual. Kauffman's description of Omphalia gracillima
more than likely applies to M. albidula also. He separated 0. albidula