Mongrels and Hybrids: The Problem of "Race" in the Botanical World

My difficulty probably is that I do not know the exact meaning ofwords like species, speciation, populations, reproductive isolation, allopatric and sympatric speciation, geographic and ecological isolation as applied in your paper. If I am wrong in my interpretation ofthem would you therefore kindly correct me. 1 must confess that I always have difficulties in reading papers discussing terminology, for I have in mind that the living world does not lend itself too well in our rigid classifications. I feel therefore that all kinds of transitions exist between sympatric and allopatric distribution as well as between different kinds ofspecies. Scientific progress has often been delayed by a premature freezing ofour concepts into a terminology that hinders our clear thinking.