North American species of Mycena.

394 NORTH AMERICAN SPECIES OF MYCENA

The pileus is homogeneous beneath a hypoderm of more or less enlarged cells having dark-brown contents. The pellicle, which is very
poorly developed, is represented by narrow hyphae, which bind the
cells of the hypoderm together. The upper surface of the enlarged
cells (where exposed) and the narrow hyphae are both covered with
short rodlike projections. Scattered lactifers are present in the stipe.
The fungus appears to be most closely related to M. fuliginaria.
198. MYCENA MARGINELLA (Fr.) Quelet
Champ. Jura et Vosges, p. 343. 1873
Agaricus marginellus Fries, Syst. Myc., 1: 113. 1821.
Omphalia marginella Josserand and Maire, Bull. Soc. Linn. Lyon, 10: 115.
1931.
Illustrations: Text fig. 47, nos. 4-5 (p. 387).
Pileus 1-2 (3) cm. broad, obtuse to broadly convex when young
and with a somewhat incurved margin, sometimes with a rather pronounced umbo, sometimes with a somewhat depressed disc, surface
glabrous, even or slightly wrinkled, appearing rather dry and velvety,
hardly striate but the margin frequently cracks or splits radially in
age, color "fuscous" over the disc, "drab" or paler toward the margin,
not fading appreciably; flesh thin, watery (if the cap surface is cut
with a sharp instrument, drops of a hyaline liquid ooze out), brittle,
odor and taste mild; lamellae close to crowded, 26-35 reach the stipe,
two or three tiers of lamellulae, narrow, equal, broadly adnate to
arcuate-subdecurrent, sometimes interveined, edge pruinose under a
lens from projecting cheilocystidia and dull sordid brown to fuliginous,
faces pallid; stipe short, 1.5-9.5 (3) cm. long, 1-2 mm. thick, equal
or the base slightly enlarged and with scattered mycelial hairs, rather
brittle-cartilaginous, dark gray to blackish brown at first, becoming
grayish brown to almost hyaline gray, dull and pruinose at first,
becoming more or less glabrous and polished in age.
Spores 6-7.5 X 3.5-4 A, ellipsoid, smooth, the wall very delicate,
very weakly amyloid; basidia four-spored; pleurocystidia present only
near the gill edge and similar to the cheilocystidia; cheilocystidia
abundant, of two types, saccate and measuring 35-46 X 15-20,u, or
fusoid-ventricose with obtuse apices and 40-60 A, contents of both
kinds sordid brownish; gill trama regular, with numerous lactifers,
hardly amyloid; pileus trama with a surface covering of irregularly
arranged saccate cells 30-40 X 9-20 /, which have dull-brown con