North American species of Mycena.

EUMYCENA: DEMINUTIVAE

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46. Mycena Swartzii (Fr.), comb. nov.
Agaricus fibula var. Swartzii Fries, Syst. Myc., 1: 164. 1821.
Agaricus setipes var. acrocyanea Fries, Icon. Sel. Hymen, 1, pl. 75, fig. 4. 1873.
Omphalia Swartzi Quelet, Bull. Soc. Myc. Fr., 1: 27. 1885.
Omphalina fibula var. Swartzii Quelet, Enchir. Fung., p. 46. 1886.
Mycena fibula var. Swartzii Kiihner, Encyc. Myc., 10: 608. 1938.
Illustrations:
Text fig. 9, nos. 11-12 (p. 120).
Bresadola, Icon. Mycol., 6, pl. 274 (as Omphalia).
Fries, loc. cit.
Lange, Flora Agar. Dan., 2, pl. 61 D (as Omphalia).
Pileus 6-12 mm. broad, flat when young, the margin decurved,
at maturity the disc slightly depressed and the margin plane or
slightly raised, surface moist and at first densely pruinose from cystidia, nearly glabrous in age, color "deep slaty brown" on disc and
"vinaceous cinnamon" on the margin when young, the margin "avellaneous" at maturity and the disc "deep brownish drab" (disc violet
brown to violet gray, the margin more or less cinnamon tinged with
pink and fading to avellaneous); flesh thin and readily splitting
radially; lamellae close, 17-20 reach the stipe, one or two tiers of
lamellulae, long-decurrent, narrow at the extremities, but broad in
the notch between pileus and stipe, whitish, densely pruinose under
a lens; stipe 4-7 cm. long, 1 mm. thick, equal, cartilaginous, densely
pruinose over all, "deep slaty brown" at apex, "pinkish cinnamon"
over the lower half, finally fading to sordid violaceous gray.
Spores 4-5 X 2-2.5 y, narrowly ellipsoid, smooth, nonamyloid;
basidia four-spored; pleurocystidia and cheilocystidia scattered to
abundant, hyaline, thin-walled, ventricose-subcapitate, 42-66 X 10 -18 u; gill trama homogeneous and yellowish in iodine; pileus trama
homogeneous, the surface covered with numerous pilocystidia, 50-90
X 10-18 Lt, cylindric above an inflated base or fusoid-ventricose with
the neck greatly elongated; caulocystidia similar to pilocystidia and
very abundant.
Habit, habitat, and distribution.-Usually it occurs scattered to
gregarious in groups of six to a dozen carpophores. It fruits in the
spring, summer, or fall, depending on the weather. On beds of moss
or occasionally on debris; North Carolina, New York, Michigan,
Washington, and California in the United States and Nova Scotia
and Ontario in Canada. It is widely distributed throughout North
America, but is seldom found in large quantities.