North American species of Mycena.

TECHNIQUE AND MATERIAL

35

of iodine was employed. It is highly desirable that this test be conducted on thoroughly dried material, and it is essential that dried
specimens be used for critical work when the reaction is weak. For
ordinary purposes one can mount the parts to be studied in a drop or
two of the solution, place a cover glass on the mount, and make the
needed observations. Where my results have not checked with
Khuner's, however, I have employed the procedure he outlined. The
following solution is used: KI, 1.5 gr.; iodine, 0.5 gr.; water, 20 cc.
Mix one part of this solution with one part chloral hydrate. Place
the specimens to be examined in a drop on a slide and allow them
to stand several minutes. XWash out the iodine solution with an
aqueous solution of chloral hydrate and make the examination by
means of daylight.
MATERIAL EXAMINED
The manner of citing the collections requires some explanation.
The descriptions, unless otherwise qualified, have been drawn from
fresh material that I collected. My collections have been cited first
in order to allow the reader to ascertain quickly my acquaintance
with the species as it occurs in nature. The number of collections
cited, however, is not necessarily a true criterion of the completeness
of the data on a species. One large collection may be infinitely more
valuable than a dozen in which each contains only a few fruiting
bodies. M. subincarnata and M. monticola furnish an example of this.
The number of collections listed for both is the same, but to me M.
monticola is much more accurately known because of the large number
of carpophores studied. An additional point should also be made:
Even though the number of collections is large, it does not mean that
all the specimens I have seen and studied are recorded. One does
not preserve all the material of the well-known and common species
that he has collected.
After the citation of the material studied in the fresh condition,
other material that has been identified or confirmed is listed. The
names of collectors are arranged in alphabetical order. Much material, particularly Atkinson's and Peck's collections, still remains
unidentified and is not cited here. Most of these collections fall in the
confusing series of species in the Typicae of Eumycena, in which it is
very difficult to identify even fresh collections.
As a rule, it is not advisable to describe new species of Mycena
from dried specimens and notes sent in by collectors. As a result of