North American species of Mycena.

214 NORTH AMERICAN SPECIES OF MYCENA

spurious collar, subdistant to distant, narrow to moderately broad,
concolorous with the pileus or pallid, edges dull brown to olivaceous
brown, rarely somewhat reddish brown in young specimens, intervenose; stipe 1-3 (5) cm. long, 1.5-2.5 mm. thick, equal or enlarged
slightly at the base, usually curved, fragile and hollow, pale gray to
avellaneous over all, apex pruinose, glabrous toward the base, which
is furnished with scattered white mycelial hairs.
Spores 10-12 X 5-6 A (four-spored), 10-14 X 6-8 u (two-, threespored), ellipsoid, smooth, amyloid; basidia two-, three-, four-spored;
no pleurocystidia; cheilocystidia 33-65 X 8-14,, fusoid-ventricose,
smooth, occasionally forked, contents homogeneous and dull brown;
gill trama homogeneous, of broad interwoven cells which are vinaceous
brown in iodine; pileus trama with a well-formed nongelatinous
pellicle, a broad hypoderm, and the remainder floccose, all but the
pellicle vinaceous brown in iodine.
Habit, habitat, and distribution.-Scattered on dead branches and
trunks of alder in August and September; rare; Northern Michigan
and Washington in the United States and Ontario in Canada.
Material studied.-Smith, 33-440, 33-471, 1359, 3073, 4156.
Observations.-This fungus was first reported for North America
under the name M. olivaceomarginata Massee sensu Kiihner. In
Ktihner's later work (1938), however, it is referred, as above, to
Karsten's species. Massee described M. olivaceomarginata as having
small spores, so that it is hardly logical to place a large-spored fungus
under this name. The species is almost the counterpart of M. rubromarginata in habit, color, stature, and consistency but differs in the
sordid olive-gray to yellow-gray colors that develop, especially along
the gill edges.
99. MYCENA ATROMARGINATA (Lasch) Saccardo sensu Kiihner
Encyc. Myc., 10: 424. 1938
Agaricus atromarginatus Lasch, Linnaea, 3: 387. 1828.
Illustrations:
Text fig. 23, nos. 3-4 (p. 212).
Fries, Icon. Sel. Hymen., 1, pl. 78, fig. 3.
Pileus 22-35 mm. high, obtusely conic, 14-32 mm. across the base,
the margin tending to recurve, long-striate or somewhat sulcate,
grayish brown on the disc, the margin pale and sordid but translucent,
very slightly wrinkled-fibrillose under a lens. Flesh thin, concolor