The veiled species of Hebeloma in the western United States / Alexander H. Smith, Vera Stucky Evenson, and Duane H. Mitchel.

Introduction

3

with assistance from their husbands in the fieldwork, made the best
study to date on the mushroom flora of the coastal region of Alaska.
Mr. Charles Barrows of Santa Fe, New Mexico, has continued his
efforts to collect the fleshy fungi of our semiarid Southwest.
Appreciation is extended to Dr. Sue Pratt of the University of
Utah, Department of Biology, for her generosity, her skill with the
scanning electron microscope, and her enthusiastic interpretation of
the results of the microscopy. The authors also extend thanks to Dr.
L. H. Wullstein of that department for his original suggestions and
personal support of the project. It should be pointed out that, while
these studies have not been used to date in differentiating between
species, they have, more importantly, confirmed the homogeneity of
the genus.
The Region Covered
The region covered in this work is that area west of the Great
Plains north of Mexico to Alaska. It is a large and physiographically
diversified region in climate and topography. Collections have been
made in the area by Smith from 1935 to the present. Locations in
which major collecting effort was centered include the Olympic Mountains of Washington; the northern Cascade Mountains including the
Mount Shuksan area; the Mount Hood National Forest of Oregon; the
Siskiyou Mountains of southern Oregon; and on the Pacific Coast,
from Cape Flattery, Washington, south to Eureka, California. For
collections from the part of California south of Eureka we are indebted
to Professor Harry D. Thiers of San Francisco State University.
In the Rocky Mountains we have collected in the Priest Lake
district of Idaho on several occasions; in the Salmon River district to
the south; and, with assistance from Mrs. Ted Trueblood of Nampa,
Idaho, collections were obtained from southwestern Idaho and southeastern Oregon. Dr. Kent McKnight contributed collections from the
Uinta Mountains of Utah, and Dr. Wilhelm G. Solheim and Smith
collected in the Medicine Bow National Forest of Wyoming.
The most intensive collecting effort, however, was made in Colorado where eight successive seasons were spent by various collectors:
Shirley W. Chapman, Evenson, Mitchel, and Smith. Contributions of
material were made during several seasons by the membership of the
Colorado Mycological Society. As a result of this combined effort the
Hebeloma flora of Colorado had been more intensively studied than
that of any other area in North America. Chapman, Evenson, and
Mitchel collected extensively in the Front Range from around Idaho
Springs to north of Rocky Mountain National Park. Mitchel collected
extensively in Eagle County. Evenson, Mitchel, and Smith have col