North American species of Mycena.

278 NORTH AMERICAN SPECIES OF MYCENA

were 7-10 X 5-7 u. Occasional two-spored basidia were found in
nearly all pilei examined, and they probably account for the variability in spore size. The sterigmata of the two-spored basidia were
of the same size and shape as those of four-spored individuals, and
as a result it was difficult to be certain of the two-spored condition or
to be sure that spores from the bispored basidia were larger than those
produced on the other basidia.
Mycena hudsoniana is very closely related to M1. subplicosa Karsten, but can easily be distinguished by its more fragile stipe, which
readily splits longitudinally into several segments when broken or
even while still intact and growing. It is also distinguished by its
much larger size, larger cystidia, lack of ochraceous tints on the margin of the pileus in age, and, apparently, by its habitat. In its fragile
stipe it is similar to M. plicosa but differs in its larger spores and in
not staining reddish when bruised or in age. As previously pointed
out, however, the latter character should not be emphasized. When
revived in KOH, specimens of M. plicosa have a thicker pellicle, but
neither species is viscid when fresh.
133. MYCENA PLICOSA (Fr.) Gillet
Les Hymen., p. 270 1874
Agaricus metatus (3 plicosus Fries, Syst. Myc., 1: 145. 1821.
Agaricus plicosus Fr., Epier. Syst. Myc., p. 110. 1838.
Illustrations:
Plates 50 B, 52; Text fig. 33, nos. 4-5 (p. 275).
Fries, Icon. Sel. Hymen., 1, pl. 81, fig. 4.
Smith, Mycologia, 27, fig. 1 c.
Pileus 1-2(3) cm. broad, convex to broadly subconic at first,
the margin appressed or slightly incurved, becoming hemispheric to
expanded and broadly umbonate, surface dry and densely pruinose at
first, slowly becoming naked and fairly moist, glabrous, when young
blackish or very dark grayish brown, becoming "drab" to "avellaneous" or dull lead color and unicolorous, hardly hygrophanous,
sulcate-striate to scalloped on the margin or halfway to the disc;
flesh grayish to pallid, very rigid but brittle, thin, odor and taste not
distinctive; lamellae close to subdistant, 20-32 reach the stipe, one or
two tiers of short individuals, narrow to broad (2.5-4 mm.), adnate
and with a slight tooth at times, drab to grayish or creamy or with a
faint flesh tint discernible in age, often staining reddish brown where