Systematics Section / ASPT
Moore, Abigail J. , Bohs, Lynn .
A Combined ITS and ETS phylogeny of Balsamorhiza and Wyethia (Asteraceae: Heliantheae).
Balsamorhiza and Wyethia are two genera of the Asteraceae native to western North America. They are united by their possession of large taproots with balsam-scented resin and a chromosome base number of x = 19. Balsamorhiza and Wyethia are separated based on leaf characteristics. Balsamorhiza has basal leaves only, which are either cordate or pinnately divided. Wyethia always has stem leaves; some species also possess basal leaves, which are ovate or lanceolate. Our previous results from ITS sequence data indicate that Balsamorhiza and Wyethia together form a monophyletic group as hypothesized based on morphology. Balsamorhiza alone is also monophyletic, while Wyethia is paraphyletic with Balsamorhiza nested within Wyethia. Within Wyethia we found one well-supported clade composed of all members of sections Wyethia and Alarconia, as well as W. bolanderi from section Agnorhiza. This clade contains all of the species of Wyethia that have basal leaves and W. bolanderi, which lacks them. The rest of the species of Wyethia, all members of section Agnorhiza, are part of a polytomy at the base of the Balsamorhiza/Wyethia clade. Thus, Balsamorhiza appears to have been removed from Wyethia because of its distinctive leaf arrangement and morphology, and it might be argued that Balsamorhiza should be subsumed into Wyethia. ETS results support the monophyly of Balsamorhiza and the paraphyly of Wyethia and provide better resolution of the relationships of Wyethia section Agnorhiza.
1 - University of Utah, Department of Biology, 257 S. 1400 E., Salt Lake City, Utah, 84112, USA
Presentation Type: Paper
Location: Cottonwood B (Snowbird Center)
Date: Monday, August 2nd, 2004
Time: 9:15 AM