There is a great deal of discussion on the species concept. Look at Eliot
Sober's book on the Philosophy of Biology (I think that is the tltle). The
(in)ability to reproduce is often used to delineate species, but this
breaks down with plants. It applies better to animals.
Steve
++++++++++++++++++++++++++++++++++++++++++++++++
Steven S. Clark, Ph.D. Ph: 608-263-9137
Associate Professor FAX: 263-4226
Dept. of Human Oncology ssclark@facstaff.wisc.edu
University of Wisconsin
School of Medicine
600 Highland Ave
Madison, WI 53792
http://www1.bocklabs.wisc.edu/profiles/Clark,Steven.html