XVI International Botanical Congess

Recent studies of plant populations indicate population-level genetic differentiation structured by the Wisconsin glaciation of North America. Disjunct occurrences may harbor descendants of ancestral populations which survived in isolated glacial refugia. We contrasted isozymes of disjunct Lycopodium dendroideum populations with those from continquous northern populations. Included in the analysis were representative individuals of other Lycopodiaceae. Eleven enzymes were resolved, and yielded clear and consistent banding. We detected no intraspecific variability in L. dendroideum, although interspecific distinctions were evident. Intersimple sequence repeat (ISSR) markers have yielded intra- and interspecific variability in L. dendroideum. These data bases indicate ISSR markers may more successfully resolve intra-population differences than isozyme studies.