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AMERICAN PASSIFLORACEAE 475
defined species may be separated, species which, it might have to be
admitted, freely intergrade; (3) certain major characters may be
selected upon which a few species may be recognized, these being
subdivided into smaller units; (4) a single species may be maintained,
with an elaborate scheme of subspecies, varieties, subvarieties, forms,
and subforms; or (5) a single species may be recognized, with numerous
varieties of unequal rank.
As a result of the examination of several thousand specimens of
"P. foetida," I have decided to adopt the last course, with this
exception: a few variants that have an assemblage of characters,
though only vegetative ones, that make them stand out from the
others I have recognized as full species; these are P. Urbaniana, P.
arida, P. fruticosa, P. chrysophylla, and P. bahamensis. The other
species of the subgenus Dysosmia, P. lepidota, P. Palmeri, P.
pectinata, and P. vestita, differ from P. foetida in flowers or fruits.
In the present monograph I am recognizing 37 varieties, in addition
to typical P. foetida.
All but two of these have a limited geographical
distribution. The variety hispida is widely distributed,
but throughout its range exhibits little variation. The variety
gossypifolia has an even wider distribution, and there is considerable
variation in the specimens which I refer to it. Perhaps this should
be subdivided. It merges into the typical form and into many of
the varieties.
In the letter previously mentioned, Masters also writes, "I suspect
they [plants of P. foetida] intercross freely; indeed, some of them
have proved to be more fertile with someone else's pollen than with
their own." Perhaps this is the explanation for much of the variation
in P. foetida; but in the absence of direct experiments it is not possible
to determine which of the variants are mere hybrids.
The preparation of this revision has covered a number of years,
during which I have had varying concepts of P. foetida. I should
greatly prefer, of course, to review all the specimens I have examined,
in order to fit them into the present final treatment, but this is not
possible. The result is one which all monographers experience;
specimens once referred to one variety may on re-examination prove
to represent another. In such cases I have noted this uncertainty
in the text following.
In Dysosmia an individual plant, whether known from a single
mounted specimen or from specimens in two or more herbaria, or
from the living plant in the field, shows very little variation. The
outline of the leaves, for example, is far more uniform than in such