North American species of Mycena.

130 NORTH AMERICAN SPECIES OF MYCENA

on the disc, pallid toward the margin, sordid and pallid over all in
age; flesh thin but not markedly fragile (as is usual in small Mycenae),
odor and taste not recorded; lamellae adnate, subdistant, very narrow, white, pruinose under a lens from projecting cystidia; stipe about
2 cm. long, filiform, flaccid, hyaline white, equal, terete, glabrous and
naked, rooting in bark and debris, with strigose white hairs.
Spores subglobose to broadly ellipsoid, 7-9 X 4.5-5 A on fourspored basidia, 9-11 X 7-9, when basidia are two-spored; basidia
23-25 X 7,; cheilocystidia and pleurocystidia similar and very
abundant, broadly ventricose in the middle and tapered to a long
aciculate point, smooth, hyaline or very faintly tinged lavender,
35-50 X 6-12 ' on the edge, (50) 60-80 X 9-15 u on the faces; gill
trama faintly vinaceous brown in iodine; pileus trama with a welldifferentiated pellicle of very narrow hyphae, beneath this a welldefined region of pseudoparenchymatous tissue the cells of which
have brownish contents, the remainder of narrow filamentous hyphae,
in iodine pale vinaceous brown beneath the pellicle. Atkinson, 19802
(as M. speirea), is the four-spored form of this species.
Habit, habitat, and distribution.-Gregarious on the bark of rotting
hardwood logs; Michigan and New York.
Material studied.-Two collections from the type locality, the type
and one made September 11, 1932, by Mains and Smith. Atkinson,
19802.
Observations.-The hypoderm occupies about half the thickness
of the trama of the pileus. The cap is not corticated in a manner
similar to that of M. rorida or of species of Conocybe. M. corticaticeps should be readily recognized by its small size, large, abundant
pleurocystidia, and large spores. The choice of the name was a bit
unfortunate. Kauffman in his notes had described the pileus of
several Mycenae as corticated when in reality he was referring to the
hypoderm. At the time I studied his notes I failed to realize the
difference in the term as he applied it to Mycena and to other genera.
51. MYCENA DEBILIS (Fr.) Quelet
Champ. Jura et Vosges, p. 107. 1872
Agaricus debilis Fries, Epicr. Syst. Myc., p. 112. 1838.
Illustrations:
Text fig. 21, nos. 4-5 (p. 201).