Genetic structure of two endangered pitcher plants, Sarracenia jonesii and Sarracenia oreophila (Sarraceniaceae)

Sarracenia jonesii and S. oreophila are insectivorous perennial plants of the southeastern United States. Both pitcher plant taxa are rare and endangered. Allozyme diversity was assessed for eight of the ten extant populations of S. jonesii and 14 of the 35 remaining S. oreophila populations. Genetic diversity was low and comparable for both species (H-es = 0.086 and 0.082 for S. jonesii and S. oreophila, respectively). Mean population genic diversity (H-ep) was 0.061 for S. jonesii and 0.060 for S. oreophila. Estimates of genetic diversity were typical of those commonly associated with endemic species. Small populations of each species and geographically disjunct populations tended to maintain less genetic diversity. Indirect estimates of gene flow were comparable for S. oreophila (Nm = 1.62) and S. jonesii (Nm = 1.07).