Diversification of Ceanothus (Rhamnaceae) in the California Floristic province

Journal Article

High diversity and endemism in the California Floristic Province (CFP) are an alleged response to the late Cenozoic advent of Mediterranean-type climate in this region. Ceanothus comprises two divergent subgenera with centers of diversity in the CFP. We reconstruct the evolution of Ceanothus by using DNA sequence data from the nuclear gene nitrate reductase. We find that the timing of diversification events is related to geological and climatic history. In both subgenera, diversification is characterized by recent divergence of extant taxa and geographically structured phylogenetic relationships. A strong north-south divergence of subgenus Cerastes across the Transverse Ranges indicates that phylogenetic relationships may be structured by climatically divergent regions of the CFP. Divergence-time estimation suggests that the age of extant diversification in both subgenera is;6 Ma. This agrees with the fossil record but predates the hypothesized Quaternary (2-Ma) origin of Mediterranean-type climate in the region. © 2011 by The University of Chicago. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Burge, DO; Erwin, DM; Islam, MB; Kellermann, J; Kembel, SW; Wilken, DH; Manos, PS

Published Date

  • 2011

Published In

Volume / Issue

  • 172 / 9

Start / End Page

  • 1137 - 1164

International Standard Serial Number (ISSN)

  • 1058-5893

Digital Object Identifier (DOI)

  • 10.1086/662028