North American species of Mycena.

228 NORTH AMERICAN SPECIES OF MYCENA

22. Spores ellipsoid; pileus 1-3 cm. broad............. 109. M. scabripes
22. Spores globose to subglobose, 5-6,................ 190. M.floccipes
23. Odor alkaline when flesh is crushed............ 111. M. leptocephala
23. Odor not as above..........................................24
24. Spores subcylindric, 9-12 (13-15) X 4.5-5 (6),; pileus dark to pale
gray........................................ 110. M. Abramsii
24. Spores more nearly ellipsoid; if 9-11 A long, then 6-7,u wide....... 25
25. Pileus and stipe blackish, hardly fading, not staining reddish in age
(M. praelonga may key out here also)........ 118. M. atrocyanea
25. Pileus blackish but very hygrophanous; stipe whitish, staining reddish where bruised............................ 112. M. subvitrea
25. Pileus gray to avellaneous, or, if blackish at first, gills pallid and stipe
not staining reddish...................................... 26
26. Cheilocystidia absent, cap turning lilac when dried
105. M. syringescens
26. Cheilocystidia typically obovate-mucronate (in age becoming more
or less branched); young pilei faintly tinged vinaceous along margin (see M. plumbea also)..................... 117. M. pectinata
26. Cheilocystidia usually fusoid-ventricose to variously branched;
pileus not with vinaceous margin............................. 27
27. Stipe 9-16 (20) cm. long....................................... 28
27. Stipe 3-6 (8) cm. long.................................. 30
28. Exceedingly watery-fragile; on fern debris........ 116. M. fragillima
28. Not as above................................................. 29
29. Cheilocystidia obovoid-mucronate; on needle carpets, stipe very
brittle.................................29a
(a) Pleurocystidia absent...................... 114. M. plumbea
(a) Pleurocystidia present........... 115. M. plumbea var. robusta
29. Cheilocystidia typically fusoid-ventricose, occasionally branched;
stipe tenacious, growing on sphagnum.......... 119. M. praelonga
30. Stipe almost filiform, about 1 mm. thick......................... 31
30. Stipe 2-3 m m. thick.......................................... 32
31. With bearing and consistency of M. filopes (tall and slender), but
cheilocystidia sm ooth....................................... a
(a) Pleurocystidia absent...................... 122. M. subfusca
(a) Pleurocystidia present and distinctive...... 123. M. subfumosa
31. Very fragile and watery, growing on fern debris, western United
States...................................... 116. M. fragillim a
32. Pileus long, remaining decidedly glaucous owing to persistent hoarypruinose coating.............................. 114. M. plumbea
32. Pileus pruinose but soon naked, hygrophanous, with stannous sheen
when faded................................... 113. M. stannea