North American species of Mycena.

92 NORTH AMERICAN SPECIES OF MYCENA

cheilocystidia basidium-like or slightly longer, hardly differentiated;
gill trama homogeneous, yellowish in iodine; pileus trama with a thin
adnate pellicle, the hyphae of which are furnished with short rodlike
projections; hypoderm scarcely differentiated, the tramal body made
up of rather broad cells bound together by filamentous hyphae, the
enlarged cells slightly more numerous and more regularly arranged
beneath the pellicle, yellowish in iodine.
Habit, habitat, and distribution.-Scattered to densely gregarious
under conifers, especially fir and spruce, during the spring and summer; New York, Michigan, and Idaho in the United States and Manitoba in Canada. It is common in Michigan and very likely so
throughout northeastern North America. Bisby reports it from deciduous woods, but he also sent specimens from sphagnum bogs.
Material studied.-Smith, 32-11, 32-27, 32-382, 33-99, 33-331,
23, 1332, 1368, 1627, 4087, 6234, 6329, 8278, 13756, 13866, 14204,
15752, 15877, June 8, 18, 1932, August 21, 1929, Bisby, Manitoba.
Kauffman, September 11, 1920, Colorado.
Observations.-The glabrous pileus, long narrow spores, lack of
well-differentiated cystidia, and the white color distinguish the
species. The size as well as the shape of the pileus and the length
of the stipe vary greatly and can hardly be considered characteristic.
Locally M. gracilis can be found in almost any sphagnum bog during
late May or early June. It nearly always occurs under black spruce,
and it most frequently fruits in the zone where the lower branches of
the young trees touch the sphagnum or the surrounding chamadaphne
bushes. During very wet periods it has also been collected in spruce
plantations where the trees are old enough to form a fairly open stand.
23. Mycena subimmaculata (Murr.), comb. nov.
Omphalopsis subimmaculata Murrill, North Am. Flora, 9: 315. 1916.
Omphalia subimmaculata Murrill, Mycologia, 8: 220. 1916.
"Pileus small, convex, slightly depressed at the center, cespitose,
reaching 8 mm. broad; surface smooth, glabrous, finely striate nearly
to the center, pure-snow-white, margin entire, appressed when young:
lamellae long-decurrent, distant, rather narrow, inserted, white:
stipe very slender, cylindric, hollow, white, minutely whitish-pruinose to subglabrous, 2 cm. long, 0.5 mm. thick.
"Type collected on dead wood in woods near Seattle, Washington,