GENETIC AND MACROMORPHOLOGIC EVIDENCE BEARING ON THE EVOLUTION OF MEMBERS OF CAREX SECTION VESICARIAE (CYPERACEAE) AND THEIR NATURAL HYBRIDS

A comparison of genetic distances between the short-beaked species (C saxatilis, C membranacea, and C rotundata) and some long-beaked specie s (C. utriculata, C. rostrata, and C. vesicaria) of Carex section Vesi cariae indicates that the short-beaked group is not monophyletic. Care x saxatilis is closely related to C vesicaria, while C membranacea and C rotundata are related to C utriculata. It is proposed that C saxati lis is derived from a vesicaria-like ancestor, while C membranacea and C rotundata have evolved from a utriculata-like progenitor. Taxa iden tified as hybrids between various short- and long-beaked species are i ntermediate in morphology, heterozygous for diagnostic loci (which exh ibited a high frequency of alternative alleles in the putative parents ), and often sterile. On the basis of the evidence presented the follo wing hybrids are recognized: C x paludivagans (C rotundata x utriculat a); C x stenolepis (incl. C x grahamii, C x mainensis, C x anti-costen sis; C saxatilis x vesicaria); C x physocarpoides (C saxatilis x utric ulata); arid C membranacea x utriculata.