subspecies

[Dr. Neil Snow]

Like Curtis, I have named sympatric subspecies of plants.  This was done under
a phylogenetic species concept and I outlined the rationale for doing so in
considerable detail.  For those interested, the reference is:

Snow, N. 1997. Application of the phylogenetic species concept: A botanical
monographic perspective. Austrobaileya 5: 1-8.

Anyone who wants a reprint can email me directly and I'll be happy to oblige.

Judd et al., in a new textbook on plant systematics, have correctly pointed out
(as others did ahead of them, such as Nixon and Wheeler [1990]) that the
phylogenetic species concept means has been defined in different ways, and has
different meanings.  My approach for the recognition of phylogenetic species
stressed diagnosability with fixed characters (not the same as
"autapomorphies"), but with an added dimension that Art Cronquist used to
stress; namely, that species ought to be recognizable by ordinary morphological
means.

Further, I argued that if we apply fixation of characters as the minimum
evidence necessary to accord specific status, that in plants (at least) we
would likely see a decrease in the number of species recognized.  Given that
heritable genetic variation often manifests itself in complex ways that are
most easily recovered in multivariate space, and that this variation can be
fairly pronounced, I chose to recognize as infraspecific taxa those entities
that are recovereable in multivariate space but which lack fixed characters.
End result?  I reduced several "species" to subspecies.

>From this thread it has been clear that some believe that infraspecific taxa
cannot or should not be recognized under a phylogenetic species concept.  Based
on the literature I had read through he early 1990s I thought so too, until I
tried to apply the PSC in the field, greenhouse, and herbarium.  The paper in
Austrobaileya summarizes the logical and rationale.

The textbook I alluded to above is:

Judd, W. S., C. S. Campbell, E. A.Kellogg, P. F. Stevens. 1999. Plant
Sytematics: A Phylogenetic Approach.  Sinauer Associates, Inc. Sunderland,
Massachusetts, USA.

NS

Curtis Clark wrote:

> At 03:55 PM 11/8/99 -0400, Bill Shear wrote:
> >A few people still try to name sympatric subspecies, a logical
> >impossibility.  This doesn't always get caught on the way to publication.
> >Of course, you can argue about what constitutes sympatry.
>
> I've named sympatric subspecies: three ploidy levels in an autoploid series
> that are always separable by flower size when they grow together. Because I
> don't believe that there is a common biological meaning for subspecies, I
> can use subspecies to point out infraspecific variation when it seems
> important to do so.
>
> ----------------------------------------------------------------
> Curtis Clark                  http://www.csupomona.edu/~jcclark/
> Biological Sciences Department             Voice: (909) 869-4062
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