A phytogeography of the San Bernardino Mountains, San Bernardino County, California

The flora of the San Bernardino Mountains in Southern California is comprised of more than 1525 species, subspecies and varieties of vascular plants in 132 families in an area of 2590 km;The factors contributing to this extraordinary example of continental montane endemism are discussed, including the geology, geomorphology, weather, climate history and latitudinal orientation of the San Bernardino Mountains. The floristic contributions to the flora are analyzed and floristic and evolutionary origins of the strict and near-endemic taxa are postulated. Finally, implications of island biogeographic theory are discussed relative to the flora as a whole and with respect to long-term prospects for conservation of the endemic plant communities within the range.;An annotated flora of the San Benardino Mountains is presented as an Appendix to this paper. The flora catalogues over 15,000 collections from the range at herbaria at the Rancho Santa Ana Botanic Gardens, the University of California at Riverside and the Jepson Herbarium at the University of California at Berkeley.