Natural hybridization between Stellaria longipes and Stellaria borealis (Caryophyllaceae)

Multivariate principal components analyses of seven morphological characters of a putative hybrid population (located at Plateau Mountain, Kananaskis, Alberta) indicated the occurrence of hybridization between Stellaria longipes and Stellaria borealis. Although the putative hybrid population had intermediate morphology between the two species, it clustered closer to that of S. longipes. Electrophoretic analysis of 15 isozyme loci confirmed that the putative hybrid population was a result of hybridization and possibly introgression. Unique alleles of both species were present in the hybrid, although they were more often attributable to S. longipes. The genetic identity and the level of genetic variability of the hybrid was of an intermediate level between the two species, but closer to that of S. longipes. Key words: natural hybridization, Stellaria longipes, Stellaria borealis, introgression, isozymes.