North American species of Mycena.

220 NORTH AMERICAN SPECIES OF MYCENA

apparently not well understood in Europe. Rea reduces it to a
variety of M. avenacea, saying that it differs only in its smaller spores
(6-7 X 4-5,). It is described as having the gill edge sordid olivaceous, a rather striking contrast to the lemon-yellow gill edges of my
Washington collections. However, this does not exclude the possibility that the two are synonymous. The situation in regard to the
color of the gill edges may be the same as that discussed under M. citrinomarginata.
102. MYCENA AVENACEA (Fr.) Quelet, sensu Kiihner
Encyc. Myc., 10: 413. 1938
Agaricus avenaceus Fries, Syst. Myc., 1: 150. 1821.
Illustrations:
Text fig. 24, nos. 3-5 (p. 216).
Konrad et Maublanc, Icon. Sel. Fung., pl. 223, fig. 2 (very good).
Lange, Flora Agar. Dan., 2, pl. 49 B.
Pileus (5) 10-20 mm. broad, obtusely conic with an appressed
margin when young, becoming broadly conic to campanulate, pruinose but soon naked and glabrous, striate to the disc with darkcolored striations when moist, soon sulcate-striate and with a flaring
margin (which has a faint incarnate tint), hygrophanous, fading
through "olive brown" to sordid olive or yellowish gray; flesh thin,
fragile, odor and taste not distinctive; lamellae ascending and adnate
with a slight tooth, distant to subdistant, moderately broad, pallid
to grayish, edges even and concolorous or very faintly reddish brown;
stipe 2-4 cm. long, 1-1.5 mm. thick, strict, equal, hollow, fragile,
pruinose above, glabrous downward or the base sparsely mycelioid,
concolorous with the pileus and fading with it.
Spores 9-12 (13) X 4-5.5 A, subcylindric to narrowly ellipsoid,
weakly amyloid; basidia four-spored; pleurocystidia not differentiated; cheilocystidia 32-40 X 9-14y, broadly fusoid to ventricose,
the neck tapered to the obtuse apex or variously branched, the enlarged portion often giving off fingerlike branches, content reddish
brown; gill trama weakly amyloid; pileus trama with a thin adnate
pellicle from which numerous pilocystidia often arise (the cystidia
15-20 X 5-7,, cylindric and with obtuse apices or merely filamentous), hypoderm well differentiated, all but the pellicle pale sordid
brown in iodine.
Habit, habitat, and distribution.-Single to scattered. I have one