Intrapopulational cpDNA haplotype diversity has been determined for four species of Packera from southwestern Alberta. Packera cana and P. pseudaurea are both low elevation species, the former of prairie habitats, the latter of more mesic sites. Packera contermina and P. cymbalarioides are both alpine species, the former endemic to the Rocky mountains of southern Alberta and the latter more widespread in regions further south. A total of 26 populations were surveyed for restriction site variation using enzyme-probe combinations known to reveal intrapopulational polymorphisms in these taxa. A total of 24 haplotypes were detected among the populations with only two haplotypes shared by all four species. Both P. cana and P. contermina contained unique haplotypes. Most of the haplotype diversity detected so far in the genus is found in the southern Alberta populations. Overall haplotype distribution patterns suggest that one haplotype group is found predominantly west of the Rocky mountains while the other major group is more widespread. Both haplotype groups are represented in southern Alberta, suggesting that the high levels of haplotype diversity may be the product of past migrations and hybridization events. Within species comparisons of interpopulational haplotype diversity reveal different patterns. Between population differences are higher in the alpine species while within P. pseudaurea, haplotype diversity is higher in more northern populations.

Key words: biogeography, cpDNA, hybridization, Packera, polymorphism, Senecioneae