Salywon, Andrew , Hodgson, Wendy , Ontl, Todd , Wojciechowski, Martin F. .
Endemic Plants of Arizona: A Working List and Initial Insights.
In the Flora of Arizona, Kearney and Peebles (1964) estimated that roughly 5% (ca.164 spp.) of the flora is endemic to the state, and identified southern Arizona as harboring nearly double the number of endemic species compared to other parts of the state. However, no list of endemic taxa was provided and many new endemic taxa have since been described. Therefore, in order to make meaningful comparisons of the endemic diversity with other states and to identify “hotspots” of endemicity within Arizona, we are compiling and annotating a list of the endemic plant taxa in Arizona. Our working list is composed of ca. 250 taxa from 43 families and identifies the northern portion of the state (namely the Arizona Strip and the Grand Canyon) as harboring the highest percentage of endemics, in contrast to Kearney and Peebles analyses. It is hoped that insights into the relationships between geographical patterns and biological processes that can be gained from the list, including comparisons of the timing and mode of evolution of different groups. For example, Astragalus, Perityle, Agave, Eriogonum and Penstemon have been identified as the genera with the most endemic species. Not surprisingly these genera are composed of mostly annuals to short-lived perennials, with the exception of Agave, and are in groups that have undergone rapid and recent diversification in the Quarternary. In contrast, the woody endemics Berberis harrisoniana, Rhus kearneyi ssp. kearneyi, Sophora arizonica (=Calia) and Pursia subintegra are most likely of Tertiary origin and relictual. Hybridization and polyploidy are common characteristics of the neoendemics, while topology and the age and composition of geological substrate are important factors for both paleo and neoendemics.
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1 - Desert Botanical Garden, 1201 N. Galvin Parkway, Phoenix, AZ, 85008, U.S.A.
2 - Iowa State University, Department of Ecology and Evolutionary Biology, Ames, Iowa, 50010, U.S.A.
3 - Arizona State University, School of Life Sciences, P.O. Box 874601, Tempe, Arizona, 85287, USA
Flora of Arizona
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Wednesday, July 29th, 2009
Time: 4:30 PM