North American species of Mycena.

78 NORTH AMERICAN SPECIES OF MYCENA
11. Spores ellipsoid............................... 32. M. pusillissima
11. Spores ventricose in middle, subfusoid........... Delicatula integrella
12. Spores 12-16 X 7-8 A.......................... 24. M. McMurphyi
12. Spores smaller............................................... 13
13. Caulocystidia abundant, the walls slightly thickened; pilocystidia
similar, scattered to abundant.................. 20. M. crispula
13. Caulocystidia absent or a few thin-walled flexuous hairs present.... 14
14. Hyphae of pellicle with short projections............ 25. M. albidula
14. Pellicle not differentiated, surface cells smooth...... 27. M. ignobilis
15. Spores three times as long as wide or longer...................... 16
15. Spores broader in relation to their length........................ 18
16. Cheilocystidia 9-14, broad, ventricose with obtuse apices
29. M. paucilamellata
16. Cheilocystidia narrower....................................... 17
17. Spores 7-9 X 2.5-3 y, 4-spored (see M. delicatella also)
17. M. albicolor
17. Spores 9-12 X 2.5-3 M, 4-spored................... 18. M. filiformis
18. Spores 3-4.5 X 2.5 /........................ Omphalia Rhododendril
18. Spores larger............................................. 19
19. Pileus with long pilocystidia (80-150 X 8-12 p), seta-like but thinwalled and hyaline............................ 16. M. setulosa
19. Pilocystidia, when present, much shorter and, if seta-like, the walls
slightly thickened...........................................
20. Spores 5.5-7 X 3.5-4,; pilocystidia with slightly thickened walls
20. M. crispula
20. Not as above...................................... 21
21. Spores 10-12 X 4-5 Mu, slightly ventricose.......... 19. M. albissima
21. Spores smaller............................................... 22
22. Spores amyloid......................................... 23
22. Spores nonamyloid.............................. 173. M. hiemalis
23. Spores 8-11 X 5-6,.......................... 31. M. kalalochensis
23. Spores 6-8 X 3-4 3i............................... 0. litoralis
24. Cheilocystidia clavate-roughened......................... 25
24. Cheilocystidia fusoid-ventricose................................. 35
1 These spore measurements were obtained from the type. Murrill gave them
as 7-5 X 3 p. I suspect that Marasmius resinosus has been confused with Omphalia Rhododendri, and it may be that the two are not distinct. Small spores are
frequent in mounts of Marasmii, and they may account for my observation. At
all events the two species should be in the same genus, Marasmius.