Sarracenia comprises eleven species of leaf-pitcher carnivorous angiosperms that are concentrated in the southeastern United States, with S. purpurea ranging more widely north and west. Although previous sequencing work has indicated that Heliamphora is sister to a monophyletic Sarracenia, and that the western North American Darlingtonia is sister to Heliamphora + Sarracenia, little resolution among the closely related Sarracenia species has emerged. In this study, DNA sequencing of plastid spacer regions has uncovered sufficient variation to construct a plastid DNA cladogram for the species. Two principal groups of species are resolved - one clade comprising S. minor, S. oreophila and S. jonesii, and another comprising the remainder of the species. In the former clade, S. minor is sister to S. oreophila + S. jonesii, both species of mountain habitats and of conservation concern. Sarracenia minor is more broadly distributed on the coastal plain, as are many of the species in the other principal clade, which includes S. flava, S. purpurea, S. rubra, S. alabamensis, S. leucophylla, and S. psittacina. The placement of S. rubra and S. jonesii in different clades contradicts previous hypotheses of relationship, in which they have sometimes been considered conspecific entities. This relationship is subject to further population sampling, as plastid introgression is also a possible explanation for the pattern. The diminutive stature that characterizes both S. purpurea and S. psittacina appears to be apomorphic in the genus and independently derived.

Key words: phylogenetic relationships, plastid DNA, Sarracenia