North American species of Mycena.

66 NORTH AMERICAN SPECIES OF MYCENA

SECTION CORTICOLAE
The members of this section form a series of closely related species
with M. corticola at one end and M. subcana at the other. In M. corticola and M. pseudocorticola the spores are globose and the cheilocystidia are of the roughened type. In M. subcana the spores are
ellipsoid and the cheilocystidia are fusoid-ventricose, with an occasional one having fingerlike projections. Intermediate between
them is M. madronicola, with the exact habit of M. corticola but with
ellipsoid spores and cheilocystidia which vary from the typically
clavate-roughened type to almost fusoid-ventricose. M. corticalis
has cheilocystidia with numerous contorted fingerlike projections
and almost globose spores, but is larger in stature than M. corticola
and, along with M. subcana, approaches the fragile gray species of the
section Typicae. M. supina is not included in this series. As I have
found it, it appears to be more closely related to those species here
grouped in the section Deminutivae.
KEY TO SPECIES
1. Cheilocystidia fusoid-ventricose or only a few clavate individuals
present, sometimes the neck greatly elongated, occasionally with
fingerlike prolongations; carpophores often growing singly on lowhanging dead branches or in tops of fallen trees usually well off the
ground, but also over bark of standing trees......... 15. M. subcana
1. Cheilocystidia clavate, apices echinulate or covered with short or long,
often contorted, projections.................................. 2
2. Spores globose.................................. 3
2. Spores ellipsoid or broadly ellipsoid.......................... 5
3. Pellicle gelatinous; stipe minutely pubescent.... M. pachyderma, p. 65
S. Pellicle not gelatinous.................................... 4
4. Color of carpophore gray to blackish...... M. supina (Deminutivae)
4. Color of fruiting body decidedly purplish to reddish brown when
young......................................... 11. M. corticola
4. Color bluish gray to gray when young; pigment in vacuoles
12. M. pseudocorticola
5. Spores 4.5-6,u wide............................ 13. M. madronicola
5. Spores 7-9 / wide.............;.;.......;..... 14. M. corticalis