XVI International Botanical Congess

The North American Cheloneae include Chelone (4 spp), Chionophila (2 spp), Keckiella (7 spp), Nothochelone (1 spp), and Penstemon (ca. 275 spp). Data from nuclear rDNA ITS sequences, plastid matK sequences, and ISSR markers were used to assess relationships among genera of Cheloneae and to examine relationships within the large and diverse genus Penstemon. Outgroup taxa included Collinsia, Pennellianthus, and Tetranema and representatives of other tribes of Scrophulariaceae. ITS data were not able to resolve relationships within Penstemon, whereas ISSR markers yielded more details. Phylogeny reconstruction based on matK was also useful for resolving relationships among genera and yielded some structure within Penstemon. Keckiella is sister to all the other North American Cheloneae. Chelone and Nothochelone are sister taxa, whereas the phylogenetic placement of Chionophila is sensitive to alignment parameters. Within Penstemon, subgenus Dasanthera forms a monophyletic group sister to the rest of the subgenera, but relationships among and within other subgenera are not as well-defined.