North American species of Mycena.

EUMYCENA: DEMINUTIVAE 77
The vinaceous-gray to bright-colored species grouped in this section impress me as being an isolated group which for the most part
was derived from small forms of the typical species rather than
from the Adonidae The gray forms intergrade imperceptibly with
the smaller species of the section Typicae. In fact, one must reconcile himself to trying both groups when keying out intermediate
forms. To include all these in both keys would make both unwieldy
and would give a false impression of the species, particularly to investigators not experienced in the study of small agarics.
KEY TO SPECIES
1. Pileus white or whitish....................................... 2
1. Pileus colored-grayish, violaceous, vinaceous, bright red, yellowish,
orange, or some other color; some fading to white in age......... 24
2. Cheilocystidia with roughened apices or with numerous projections
over apices (but see M. papillata also)....................... 3
o2. Cheilocystidia, if differentiated, smooth (or only a few forked)..... 5
3. Spores 7-8 X 5.5-7.5,u (2 spored; 4-spored form not known)
34. M. minutula
3. Spores longer (up to 10 A, or more in 4-spored forms).............. 4
4. Spores 10-13, long (4-spored); gills lacking (faded forms of M.
capillaris key out here, but its gills are well formed)
33. M. cylindrospora
4. Spores 7-10 X 3-4.5 u; stipe 3-24 mm. long (see Kuhner, 1938, for
description)................................... M. polyadelpha
5. Cheilocystidia not differentiated or not known.................... 6
5. Cheilocystidia well differentiated................................ 15
6. Spores ellipsoid..................................... 8
6. Spores globose, cheilocystidia not known......................... 7
7. Stipe glabrous................................... 28. M. papillata
7. Stipe pubescent................................. 26. M. subvestita
8. Spores 10-12 X 2.5-3,........................ 21. M. mauretanica
8. Spores 7-9 X 2.5-3, (4-spored).................... 22. M. gracilis
8. Spores broader than in choices above............................ 9
9. Gills narrow, almost foldlike at times............................ 10
9. Gills broader and more or less triangular, at least in age........... 12
10. Spores 8-11 X 3.5-4 (12-14 X 4-5 gt; 2-spored). 23. M. subimmaculata
10. Spores up to 9 u long.......................................... 11