The North American species of Psathyrella.

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MEMOIRS OF THE NEW YORK BOTANICAL GARDEN

[ VOL. 24

little or nothing to a stabilization of the nomenclature, though they did maintain
Quelet's broad concept of the genus. They treated the species under the name
Drosophila, an invalid name by any interpretation of the International Rules of
Nomenclature. Further, a descriptive key simply is not the vehicle for the lucid
presentation of diversity in a large and complex group of organisms as poorly
sampled over all the earth's major land masses as is true for Psathyrella! Moser's
(1967) key is, as is that of Kiihner & Romagnesi (1953), helpful; but it still suffers
from the limitations of a descriptive key in that it does not allow properly critical
comparisons to be made between the floras of Europe and other major land masses.
This situation derives from the fact that in a descriptive key a studied attempt is
made to avoid detailed descriptions, and data not important to one author may
be to others.
It is evident that the outstanding effect of scattering obviously related species
in a number of genera (Saccardo, 1887) delayed the general recognition of the true
scope of Psathyrella as a genus for nearly 50 years, and, accompanying this,
created many uncertainties relative to the use of many species epithets. All of
this added up to neglect for the group, and discouraged innovation in its systematics. Certainly this was true for work in North America where investigators
were concerned for the most part secondarily with psathyrelloid fungi. Morgan's
(1907-08) work is an exception.
In North America, Peck, Atkinson, Murrill, Kauffman, Morgan, and Parker,
in their various works, followed the "Friesian tradition" as embodied in Saccardo
(1887). In speaking of the "Friesian tradition" it should always be remembered
to the credit of Fries, that he visualized all these species as belonging in a single
genus. Murrill (1922, et al.) used the old American Code of Nomenclature and
hence applied different generic names to the Saccardoian genera. For instance,
he used Drosophila, but not in the sense of Quelet. For North America, studies
were largely confined to describing species. These are treated in the body of the
text and will not be summarized here.
My own contribution over the last forty years has been a continuation of the
delimitation of species, and finally the proposal of an infrageneric classification
on a broader scale than that attempted by any other investigator or group of
them. But I hasten to point out that the sampling of the North American
Psathyrella flora is as yet hopelessly inadequate for any final conclusions.
It has been considered impossible to deal successfully with all nomenclatural
problems. The final disposition of the names for European species must rest upon
the selection of a neotype for each species, and, as I have previously indicated
(1970), the only acceptable procedure scientifically is that of collecting each species in its "type" country (that from which it was described), redescribing the
material completely so that other investigators can compare the description of
the macroscopic features with those given in the original description to be sure
of proper agreement, and, of course, to determine the microscopic features from
the collection itself. Merely selecting a collection "seen by Fries" does not constitute a sufficiently critical approach for typification in view of the complexity
now known for the genus.
Since Singer's infrageneric classification is the point of departure for that used
in the present work, the following outline (Singer, 1963) is given including mention
of the type species of each taxon.