North American species of Mycena.

32 NORTH AMERICAN SPECIES OF MYCENA

cause of dry weather. There were periods of both good and poor
collecting in the Great Smoky Mountains of Tennessee and North
Carolina. As can readily be seen, the emphasis was placed on the
North Temperate species. There appears to be a rather sharp
difference between these and the tropical Mycenae. A study of the
latter would bring up many questions which can be answered only by
a rather complete survey of the tropical species of Marasmius as well
as of Mycena. This in itself is a task more than equal to the one I
have undertaken.
The collecting, photographing, and studying of the fresh material
was carried out according to an established routine. Because of the
delicate nature of most species I found that best results could be
obtained by collecting the material in the morning and studying it in
the afternoon of the same day. When the specimens were collected
they were carefully wrapped in waxed paper to prevent loss of moisture or damage by rain. Those to be photographed were usually
wrapped separately and placed upside down in coffee cans. Placing
the specimens cap downwards in the cans prevented further elongation
of the stipes, and the carpophores remained just as they were when
collected. If stood more or less upright, the stipes usually curved
in such a manner as to orient the pilei for spore discharge, a condition
in which they were not so desirable for photographs.
Whenever the material was adequate, a complete description was
made from the collection. A few pilei were usually placed on slides,
gills down, and by the time most of the description was written good
spore deposits had been made. The chart employed for color notes
was that of Ridgway (1912), and all color terms in quotation marks
are from that source. The photographs of the very delicate forms
were taken as soon as the notes were recorded. The more durable
species were usually left in their packages until evening, when photographs were taken with the aid of artificial light. A 9 X 12 cm. filmpack camera with a Schneider f. 4.5 lens was used. A Weston exposure
meter served to determine the time of exposure. The specimens were
arranged against either a white cardboard or a black velvet background, depending on the color of the specimens to be photographed.
Film packs made it possible to take a large number of photographs
at one time and to do the developing at one's convenience.
As soon as the notes and photographs were completed the collection was placed on a drying apparatus. The most satisfactory apparatus for drying large numbers of specimens consisted of the racks