North American species of Crepidotus, by L.R. Hesler and Alexander H. Smith.

PREFACE
During the years of our joint endeavors on the study of fleshy fungi
one feature has stood out clearly from all others, and that is that all groups
of fleshy fungi in North America have been in need of critical study. Though
our published efforts to date have been mostly on Hygrophorus (1963) and
Lactarius (1960a, 1960b, 1962), we have not neglected other groups in our
collecting. We had no particular motive in signalling out Crepidotus for
critical study other than that the literature on it seemed to be more inadequate than usual as far as being able to use it accurately to identify specimens. In our attempt to correct this situation we have pooled our resources
and the result is a treatise which we hope will put the concept of the species
in Crepidotus in a more meaningful light than it has been heretofore. The
following treatment is organized along the lines of our other presentations,
and on the basis of morphological and anatomical characters. The coverage for North America, though more complete than in any other previous
treatment, is not to be considered adequate on any ultimate basis.
Any extensive taxonomic revision depends not only on the accumulation of much new material, but also a critical restudy of the type specimens
of species already described, as well as studying much material as preserved
in herbaria to fill out patterns of distribution. Without help from the
numerous curators of collections containing specimens of Crepidotus, this
work could not have been completed. We are indebted to Dr. G. Taylor,
Director, Royal Botanic Gardens, Kew, England; Director Dr. Albert Pilat,
The Botanical Department of the National Museum of Prague, Czechoslovakia; Curator C. Bas, The Rijksherbarium, Leiden; Curator Dr. Sten
Ahlner, The Rijksmuseum, Stockholm; Dr. Clark T. Rogerson, Curator,
Cryptogamic Herbarium, The New York Botanical Garden; Mr. StanleyJ.
Smith, The Herbarium of the New York State Museum, Albany; Dr.
Richard P. Korf, Plant Pathology Herbarium, Cornell University; Dr.
Howard E. Bigelow, The University of Massachusetts; Dr. C. R. Benjamin,
The National Fungus Collections, Beltsville, Maryland; Dr. Erdman West,
The University of Florida Agricultural Experiment Station Herbarium; Dr.
Clifford C. Gregg, Director, The Chicago Natural History Museum; Dr. I.
Mackenzie Lamb, The Farlow Herbarium of Cryptogamic Botany, Harvard
University; and Dr. D. P. Rogers, The University of Illinois Herbarium.
For support of field expeditions and the herbarium studies we both are
indebted to the National Science Foundation for assistance over a period of
many years. The Faculty Research Fund of the University of Michigan
financed much of Smith's work in the Western United States prior to the aid
received from the National Science Foundation. The University of Michigan Biological Station, A. H. Stockard, Director, was the base of operations for work in the Upper Great Lakes region from 1946 to the present.

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