North American species of Mycena.

EUMYCENA: TYPICAE

347

C. palustris have very thick gills. The spore size varies somewhat,
and when one has in hand a pileus with both two- and four-spored
basidia, the variation appears to be great. In some collections they
measure 6-8 ju long, but usually they are 7-9 A and, on two-spored
forms, 8-10 j long.
Mycena fuliginosa, M. tenacipes, M. subtenuipes, and M. atroumbonata all appear to me to belong in one species-M. hemisphaerica.
The spores in the type of M. atroumbonata measure 8-10 X 4-5 A,
but two-spored basidia were quite numerous and thus nullified the
difference in spore size. The spores of M. fuliginosa measure 6-8 X
3-4 /I; those of M. tenacipes, 7-9 X 4-5 t; and those of M. subtenuipes,
7-9 (10) X 5-6 u. There seems to be a significant difference in the
width of the spores of M. fuliginosa and M. subtenuipes, but it must
be remembered that these measurements were not made from spore
deposits or even from fresh material. In the fresh specimens I have
studied the measurements are usually 7-9 X 4-5 j, exactly intermediate between the two. I have observed a greater variation in
spore size in M. haematopus.
Mycena maculata has been separated from M. hemisphaerica by the
dark reddish-brown to purplish-brown stains that develop on all
parts of the fruiting body of the former. The distinction appears
to be a poor one in the light of my observations on the genus as a
whole, but it does serve a useful purpose here. Peck and Kauffman
apparently gave it considerable weight. I have collected both species
under identical conditions in the field and cannot attribute the difference to environmental factors. Even in dry seasons the stains are
evident in M. maculata. Both species are frequently very abundant
in Michigan.
170. MYCENA GALERICULATA (Fr.) S. F. Gray
Nat. Arr. Brit. Plants, 1: 619. 1821
Agaricus galericulatus Fries, Syst. Myc., 1: 143. 1821.
Prunulus galericulatus Murrill, North Am. Flora, 9: 336. 1916.
Collybia ligniaria Peck, Ann. Rep. New York State Mus., 54: 145. 1901.
Prunulus ligniarius Murrill, North Am. Flora, 9: 333. 1916.
Gymnopus dentatus Murrill, ibid., p. 366.
Collybia dentata Murrill, Mycologia, 8: 218. 1916.
Mycena Atkinsoni House, Bull. New York State Mus., 219-220: 233. 1920.
Mycena atridisca Murrill, Mycologia, 8: 220. 1916.
Prunulus atridiscus Murrill, North Am. Flora, 9: 334. 1916.