XVI International Botanical Congess

Species that are common throughout much of their geographic distribution often contain populations that are rare at the periphery. Genetic theory predicts that such marginal populations may be genetically differentiated from central populations, with reduced levels of genetic variation and greater population differentiation. Carex viridula provides an interesting model for examining genetic diversity in geographically marginal populations. While it is common throughout much of northern North America, disjunct populations occur in the Southwest. Allozyme analysis was used to describe genetic structure in five Colorado populations of C. viridula. It was revealed that while these populations are not genetically differentiated from central populations, they do maintain extremely low levels of genetic variation.