The North American species of Psathyrella.

1972]

PSATHYRELLA

29

conditions for fruiting are so erratic. For successful work in such areas a resident
of the region with an interest in the subject is practically a requirement. I have
been fortunate in this respect relative to the arid region of southwest Idaho and
adjacent states. Mrs. Ted (Ellen) Trueblood of Nampa, Idaho has been collecting
in the Owyhee Mountains of Idaho for years and has discovered there a substantial
Psathyrella flora. Through her efforts we are learning more about it and are
also accumulating interesting data on the total flora of fleshy fungi for this
remote region.
In Alaska Mrs. Virginia Wells and Mrs. Phyllis Kempton have for years
been working on the flora of that vast area with exceptional success as the
series of papers under their authorship indicates. They have encountered an
interesting Psathyrella flora, as is indicated by the species included in the
present work, which is going to be very important in a final comparison with
the Psathyrella flora of northern Europe.
I am particularly indebted to Mr. Peter Orton, Rannoch School, Scotland,
for time and effort spent in comparing details of the Psathyrella flora of the
British Isles with that of North America. Much remains to be done yet in this
respect, but it was evident from our preliminary effort that the genus in the
British Isles has its own pattern of complexity and that this does not coincide
too well with the North American pattern. It seemed evident that the course
leading to the best understanding of both floras was to record the diversity of
each in detail separately and then make comparisons.
Dean Emeritus L. R. Hesler of the University of Tennessee kindly turned
over his Psathyrella collections to me for study, as did several of my former
students: Dr. Howard Bigelow, Dr. Harry D. Thiers and Dr. Kent McKnight.
I regret not being able to furnish them more identifications, but at least in
many cases ideas relative to future problems were obtained.
On the basis of my own experience, it appears that any distinctive phytogeographic area in North America which supports fleshy fungi, has some species of
Psathyrella of special interest. It is my hope that the present work offered as
an introduction to the Psathyrella flora of North America, will stimulate regional
studies of significance both in the analysis of species concepts based at least
in part on laboratory studies, and on further field work to more accurately map
the distribution of our taxa. If my present effort enables future investigators
to see more clearly the problems in the genus, I shall feel that the effort has been
worthwhile.