The conservation of unisexual vertebrate populations

Ranker and Arft (1994) brought needed attention to cur-rent ambiguity in the use of the term "hybrid " and the potential confusion this ambiguity can have on the pro-tection of allopolyploid plants under the U.S. Endan-gered Species Act (ESA). This legislation denies protec-tion to hybrids under the (not explicitly stated) rationale that "hybrids " as generally understood o not constitute independent evolutionary lineages and, hence, are unde-serving of protection. Ranker and Arft correctly point out, however, that the term "hybrid, " denoting the F 1 progeny of interspecific matings, should not be con-fused with polyploid taxa that are originally of hybrid or-igin. The important distinction is that the former are evolutionary dead-ends that are most often sterile or have greatly reduced fertility relative to their parenta