Drew, Bryan T. , Sytsma, Kenneth J. .
Raven and Axelrod Revisited: Molecularly Testing the Origin of the California Floristic Province.
The California Floristic Province (CFP) extends from Southern Oregon to Northern Baja California, and is defined by a Mediterranean-type climate. The CFP has long been known for its incredible biodiversity and high degree of endemism. In a broad overview of relevant examples, Raven and Axelrod (1978) argued that Lepechinia and Salvia (Lamiaceae), among others, diversified in the CFP following dispersal from Mexico as part of the Madrean floral assemblage, approximately 10-20 million years ago in the Miocene. Raven and Axelrod´s two part hypothesis regarding a Madrean origin of the CFP (1. CFP lineages each are derived from or sister to a more southern Madrean lineage; 2. each of the stem lineages dates to the Miocene) is tested by dating the origin of Lepechinia and Salvia within the CFP using chronograms derived from the phylogenies of the Lamiales and Lamaiaceae in a stepwise fashion. These chronograms are calibrated with multiple fossils representing several subfamilies within the Lamiaceae and other families of Lamiales. Results support Raven and Axelrod´s hypothesis, and are in general agreement with the oldest known fossils exhibiting hexacolpate pollen (unique to the mint subfamily Nepetoideae).
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1 - University of Wisconsin-Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706-1381, USA
2 - University of Wisconsin-Madison, Botany, 430 Lincoln Drive, Madison, WI, 53706, United States
California Floristic Province
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Rendezvous A/Snowbird Center
Date: Tuesday, July 28th, 2009
Time: 9:15 AM