North American species of Mycena.

INTRODUCTION

7

and Africa can be similarly explained. The distribution by states
and provinces in the United States and Canada has not been summarized because of insufficient knowledge about it in both countries.
Large numbers of species have been reported for the Pacific Coast
and for North Carolina, Tennessee, New York, and Michigan in the
East because intensive collecting has been carried on in these regions.
During the course of this study over three thousand collections of
Mycenae have been studied.
ACKNOWLEDGMENTS
No extensive work such as this could have been undertaken without the help of many people and institutions. The field work in
regions distant from Ann Arbor was carried out by means of grants
from the Horace H. Rackham School of Graduate Studies of the
University of Michigan. The notes and photographs taken on these
expeditions make up the bulk of the descriptive material and illustrations. The accurate identification of the specimens, however,
would have been impossible without the cooperation of those in
charge of herbaria in which the types of American species have been
deposited. It is a pleasure to acknowledge the wholehearted support
received from Professor H. M. Fitzpatrick, of Cornell University;
Dr. Homer D. House, State Botanist, New York State Museum; and
Dr. Fred J. Seaver, of the New York Botanical Garden. Through
their aid the types of the species described by Atkinson, Peck, and
Murrill were studied and many errors have been corrected. I also
wish to express my thanks for the help given me by Dr. W. A. Murrill,
now of Gainesville, Florida, who has very kindly allowed me to examine type material of the species he has described from Florida.
I am under obligation to still other individuals and institutions
for aid given during the time this investigation was in progress.
Dr. David H. Linder,* Curator, Farlow Herbarium, Harvard University, made available to me the large number of Mycenae deposited
in that herbarium. Professor L. 0. Overholts,* of Pennsylvania State
College, placed at my disposal all the species in his private herbarium.
Dean L. R. Hesler, of the University of Tennessee, has not only
allowed me to examine the plants in the herbarium of that institution,
but has given a great deal of time to collecting material in eastern
Tennessee and the Great Smoky Mountains National Park. Through
his efforts a number of interesting species have been found. To
* Died November 10, 1946.