Systematics Section / ASPT
Scheen, Anne-Cathrine , Albert, Victor A. .
Molecular phylogenetics of the Physostegia group (Lamioideae: Lamiaceae).
The five genera Physostegia, Brazoria, Macbridea, Warnockia, and Synandra are endemic to North America. Together with the monotypic Eurasian genus Melittis and the East Asian genus Chelonopsis, they form subtribe Melitteae. It has been questioned whether these seven genera represent a monophyletic group. Indeed former morphological and cytological surveys have failed to provide characters that distinguish subtribe Melitteae from the rest of the Lamiaceae. Preliminary molecular evidence from an ongoing survey of subfamily Lamioideae also suggests this grouping to be unnatural. Based on trnL intron sequences the monotypic genus Melittis is not closely related to the Physostegia group, but is sister to a large clade containing Stachys and several other genera. However, the preliminary molecular results suggest the Eurasian/North American link to be real, pointing to a possible close relationship between the Physostegia group and the Asian genera Chelonopsis, Gomphostemma or Colquhounia. A close relationship between Synandra and Galeopsis has formerly been suggested based on similarities in pollen morphology. This hypothesis is not supported by the molecular data. In the molecular phylogeny the endemic North American taxa (the Physostegia group) form a monophyletic group that receives high jackknife support. The relationships between the taxa of the Physostegia group will be discussed in light of the molecular data.
1 - University of Oslo, Botanical Garden, Natural History Museums and Botanical Garden, P.O. Box 1172 Blindern, Oslo, NO-0318, Norway
Presentation Type: Paper
Location: Cottonwood A (Snowbird Center)
Date: Tuesday, August 3rd, 2004
Time: 10:45 AM