Re: SPEC-setosa/hookeri


>Do you remember there are two subspecies of setosa as minimum. First, Iris
>setosa grow in interior and maritime parts of Asia and only maritime parts
>of Northern America. Second, Iris setosa subsp. interior grow in interior
>parts of Asia and America. It occupy more large area in Asia than first but
>is very rare there.
>Probably there was two opposite directions of migration iris setosa in
>different eras? One could be nautical! Setosa can grow at salty soils near
>edge of sea water and its seeds don't sink up to 200 days!

>From the evolutionary point of view it is highly unlikely that the
"interior" and "maritime" subspecies of Iris setosa are the same in both
Asia and North America.  More likely the differences between interior and
maritime forms have developed in parallel in both places.

The subspecies concept is not often clearly understood.  Technically a
subspecies is a morphologically distinct population that occurs in a
geographically coherent area within the range of a species.  At least in
animals, subspecies are not expected to show reproductive isolation from
other subspecies of the same species.  In the past, there has been
considerable confusion about this concept, especially in plant taxonomy.
Some plant taxonomists named large numbers of subspecies, each one based on
single or a few specimens that appeared to them to be somewhat different.
Often these so-called subspecies came from the same place, which means that
they were simply ecological or genetic variants.  Subspecies have to be
geographically coherent and can't be sympatric (from the same locality).

I would say that most taxonomists today do not recognize subspecies
formally but instead prefer to describe the geographic variation within a
species in more detail.

Bill Shear
Department of Biology
Hampden-Sydney College
Hampden-Sydney VA 23943
(804)223-6172
FAX (804)223-6374
email<bills@hsc.edu>
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