North American species of Mycena.

134 NORTH AMERICAN SPECIES OF MYCENA

Spores 9-13 X 5-6.5 M, smooth, ellipsoid, occasionally somewhat
pear-shaped, very weakly amyloid or at times apparently not at all
amyloid; basidia four-spored; pleurocystidia and cheilocystidia
similar and very abundant, 70-90 (110) X 9-15 u, narrowly fusoidventricose and usually with abruptly pointed apices, sometimes
forked or branched near the apex, hyaline, smooth; gill trama homogeneous, dark vinaceous brown in iodine; pileus trama with a thin
but clearly differentiated pellicle, a well-developed hypoderm, and
the remainder filamentous, all but the pellicle vinaceous brown in
iodine.
Habit, habitat, and distribution.-Gregarious to scattered on humus
under hardwoods or conifers. In the United States it is very abundant along the Pacific coast from Washington to California, and also
in Tennessee and North Carolina. Kauffman failed to find it in
Michigan, and as yet my efforts to discover it there have been equally
unsuccessful.
Material studied.-Smith, 3151, 3209, 3215, 3335, 3454, 3471,
3668, 3677, 3724, 3737, 4475, 7541, 7795, 7942, 8012, 8207, 8370, 8522,
9027, 9113, 9149, 9177, 10855 16640, 16711. Atkinson, 1620, 20869,
24744, 15197 (as M. leucogala). Hesler, 6511, 7354, 9620, 12323,
12324, 14478. Overholts, Tennessee.
Observations.-M. galopus looks like a very ordinary slender gray
or blackish Mycena and, if one does not take the trouble to ascertain
the presence of a milklike fluid at the time the specimens are collected,
he may never be able to identify the collection correctly. The latex
is often scanty and not readily observed. The most accurate way to
demonstrate its presence is to break the fruiting body from its point
of attachment and carefully observe the broken base for a minute or
two. If a milklike juice is present, at least a drop will exude slowly
from the broken base. In robust specimens the latex will usually
issue readily from any cut or broken portion of the pileus or stipe.
In the laboratory one can usually identify dried material by the long
pleurocystidia, relatively large spores, and strong reaction of the
tissues of the gills and pileus to iodine. In California, where the
species has been observed to be most abundant, variations from black
to almost grayish white were seen and, at least in that region, there
appears to be no justification for separating out forms or varieties on
the basis of either size or color. I have not as yet seen any purewhite carpophores.