North American species of Mycena.

38 NORTH AMERICAN SPECIES OF MYCENA

degree of the reaction of many species and because of rather numerous
exceptions which occur throughout the genus, the character does not
appear to be of greater practical or theoretical value than the other
major characters of the fruiting body. M. pseudotenax is an example
of a typical gray Mycena with nonamyloid spores. M. monticola is a
species with echinulate cheilocystidia and nonamyloid spores; M. hymenocephala has amyloid spores but belongs in the Corticatae, the
other species of which have nonamyloid spores, and M. lilacifolia
of Glutinipes has nonamyloid spores. (Singer has transferred the
latter to Clitocybe.) I do not believe that the small white species of
Deminutivae with amyloid spores (M. cylindrospora, M. paucilamellata, M. littoralis, M. kalalochensis, and M. pusillissima) can justifiably be placed in a different genus from the other small white species
of Mycena which they resemble in most respects. The genus Delicatula would be the most logical place to put them if they were excluded
from Mycena, but their development is gymnocarpic, as in Mycena,
rather than hemiangiocarpic, as in Delicatula. In addition, they are
more closely related to Mycena because of their cystidia. In the arrangement proposed in the text I have regarded the amyloid character
as secondary when it conflicted sharply with all the other characters.
It is evident in all groups of agarics that each has developed along
particular lines which have emphasized the value of individual characters in the delimitation of species and genera. In both Leucopaxillus and Melanoleuca (the latter in the restricted sense of Patouillard) the amyloid reaction of the spores appears to be a character
which, when correlated with certain others, delimits a group of related
species of generic rank. In Mycena the amyloid character of the
spores and flesh of the carpophore does not appear to be sufficiently
correlated with any other characters to justify separating groups of
generic or subgeneric rank.
In the following outline an attempt has been made to place related
species in small groups or stirpes, each of which is named for its central
species. This arrangement is within that of the subgenera, sections,
and subsections as given in the text.
CLASSIFICATION INTO STIRPES
I. SUBGENUS PSEUDOMYCENA
A. Section Tenerrimae
1. Stirps tenerrima: M. tenerrima, M. osmundicola