North American species of Mycena.

MIJRRILL'S TROPICAL AND SUBTROPICAL SPECIES
IN THE North American Flora Murrill described a number of species
from tropical North America, but did not give much information
on their microscopic characters. Without such information it is impossible to identify these species accurately. I have studied his type
specimens and in the following account present the data obtained for
each. A key based primarily on microscopic characters to supplement that of Murrill for their macroscopic features is given below.
Since I have had no firsthand experience with tropical agarics, it did
not seem wise to try to include these species in the body of this work.
Certain of them may very easily belong in other genera, but to transfer them now, without more detailed knowledge of both Mycena and
Marasmius as these genera are represented in the tropics, might not
do more than add to the existing confusion.
In the following text the species are arranged in alphabetical order.
KEY TO SPECIES
1. Stipe with gelatinous sheath or outer layer....................... 2
1. Stipe not as above............................................ 3
2. Spores 4-5 X 2.5.................................... M. trojana
2. Spores 8-9 X 5-6,u............................ M. fumosiavellanea
3. Pileus with thick gelatinous pellicle............................. 4
3. Pileus not as above........................................... 5
4. Cheilocystidia obtuse, apices covered with short rodlike projections
M. argillacea
4. Cheilocystidia smooth, 12-20 A broad................. M. margarita
5. Cuticle of pileus hymeniform; spores 4-5 X 3-3.5..... M. pubescens
5. Pileus not as above............................................ 6
6. Spores small, ellipsoid to globose, 3-5 Is.......................... 7
6. Spores larger, ellipsoid......................................... 8
7. Fruiting body greenish gray; spores globose and amyloid M. viridigrisea
7. Fruiting body some other color (pallid gray or avellaneous), spores
amyloid, ellipsoid (see discussion of 0. myceniformis)
Omphalia myceniformis, 0. convexa, 0. roriduliformis, 0. subavellanea
7. Fruiting body lateritious; spores not amyloid........... M. latericia
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