North American species of Mycena.

54 NORTH AMERICAN SPECIES OF MYCENA

gill trama of greatly enlarged cells, pale vinaceous in iodine; pileus
trama with a pellicle which usually gelatinizes in KOH or water
mounts, the surface hyphae covered with short rodlike projections,
occasionally some of the hyphae become aggregated into peglike
structures (which project from the surface and cause the appearance
of scattered coarse spines on the cap when viewed under a 10X lens),
tissue beneath the pellicle entirely of greatly enlarged cells, which are
pale vinaceous in iodine.
Habit, habitat, and distribution. Scattered to gregarious on oak
leaves or coniferous needles, spring and summer or early fall. It is
common during warm, wet seasons. I have collected it in Tennessee,
Michigan, Idaho, and Washington in the United States and in Nova
Scotia and Ontario in Canada. Dried material from Pennsylvania
and from Manitoba, Canada, has also been studied.
Material studied. Smith, 32-468, 32-472, 32-493, 33-437, 33 -579,33-908,1615,1701,4824,7025,9668,713589,14111,14680,14819,
15751, 15858. Kauffman, Pennsylvania. Wehmeyer, 691.
Observations. Although I have complete descriptions of over
half a dozen collections, and have examined many more, the limits
of the species do not appear to be sharply defined, and the best that
can be done at present is to include under this name a series of very
closely related forms. The description given here has been drawn
from material which appeared in great quantity in a local pine plantation (Smith, 1615), but which was collected with equal abundance
both on oak leaves that had become lodged among the needles and
on the needles themselves. The variation in the cystidia appears
co be as great as that of M. citrinomarginata-a conclusion drawn
from studying the collection mentioned above. In individual collections from other localities the cystidia of some were fusoid-ventricose
3r with the apices furnished with two or more fingerlike projections.
In others the cystidia were clavate with short rodlike projections or
with obtuse, blunt contorted processes covering their apices. In
regard to gill attachment and pubescence of the bulb no clear-cut
distinctions were found in my material. The gills may or may not
form a collar around the stipe-depending upon the degree of attachment at first. If broadly attached they tend to secede and form a
collar; if the attachment is slight they may not secede at all or, if
they do, they may not adhere to each other. In some small caps
they are usually more or less distant at maturity, whereas in robust
carpophores they may be quite crowded.