subspecies summary

[Curtis Clark]

At 09:57 AM 11/12/99 -0400, Bill Shear wrote:
>Could someone clarify the question of naming plant populations which
differ
>in ploidy, and hence are probably reproductively isolated?  I gather that
>some will name these as species, others as subspecies (sympatric
>subspecies, no less!)  But to name them as subspecies seems to me to
>violate both the BSC and the PSC (which are really the same thing anyway).

Depends on the type of "ploidy". Genomic alloploids are ordinarily, and
best, treated as separate species. Segmental alloploids (e.g. the Triticum
story) are problematic, and I've never worked with them, so won't comment.
Autoploids were once recognized as separate species, but gene flow up the
ploidy ladder is not uncommon (through non-reduced gametes and additional
origins of the higher ploidy levels), and gene flow down the ladder
possible, if unusual. In many species, autoploid levels are not even
recognized, primarily because they all look alike. I gave subspecies names
to mine because they are morphologically somewhat distinct.


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