9726830 Wen Project Title: Phylogenetic and Monographic Studies in the Aralia - Panax Complex of the Ginseng Family (Araliaceae) The disjunct distribution of many morphologically similar plants in eastern Asia and eastern North America represents a well-known biogeographical pattern. However, Liquidambar, a biogeographic model in the North Temperate zone, recently was shown to have given rise to the subtropical genera, Altingia and Semiliquidambar, despite high levels of morphological cohesion in Liquidambar. These studies from Dr. Wen's laboratory strongly suggest the need for examining the evolution of other eastern Asian and eastern North American disjuncts in a broader biogeographical context, including temperate, subtropical, and tropical regions. The Aralia - Panax complex, which includes the medicinally important ginseng species, American ginseng and sanchi, is an ideal candidate for such a study. The genera consist of approximately 75 species that have a wide distribution in the temperate and tropical regions in Asia and the Americas; Dr. Wen will collect specimens for the study in Argentina, Peru, Indonesia, China, Nepal, and Vietnam. Three major groups (Panax, Aralia sect. Aralia, and Aralia sect. Dimorphanthus) have disjunct distributions in eastern Asia and North America. Previous studies by the PI documented phylogenetic patterns in each of the three lineages and suggested that the close relationship between the eastern Asian and eastern North American disjuncts has been over emphasized. The goals of this study are to 1) construct a robust phylogeny of the Aralia - Panax complex with evidence from morphology, nuclear ribosomal DNA and chloroplast DNA, 2) examine the eastern Asian and eastern North American disjunct pattern in the broader context of temperate and tropical Asia and the Americas, 3) evaluate the previous classification of the complex and examine the evolution of several frequently used taxonomic characters, 4) provide taxonomic treatments for Panax and Aralia sect. Aralia, and 5) develop a World Wide Web page on the systematics of the economically important ginseng genus, posting information on morphology and nomenclature, taxonomic keys, species descriptions, distribution maps, conservation status, ethnobotany, common names, color photographs showing diagnostic characters, and updated references. The taxonomic treatment of the ginseng genus will be valuable for future pharmacological and ecological research and for efforts to balance the conservation and the human use of these resources. This study will also provide important insights into the relative utility of different types of data for phylogenetic comparisons in plants.
