Data from: Plant diversity and endemism in the California Floristic Province

The California Floristic Province (CFP) is an area of high biodiversity
and endemism corresponding roughly to the portion of western North America
having a Mediterranean-type climate. High levels of diversity and endemism
in the CFP are attributed to the unique geo-climatic setting of the
region. In recent years, much has been learned about the origins of plant
diversity in western North America. This work, however, has been hindered
by a focus on political rather than biotic regions, such that much more is
known about diversity and endemism in the state of California than the
natural biotic region represented by the CFP. Here we present a
preliminary list of native land plants (vascular plants and bryophytes)
found in the CFP, as well as an analysis of diversity and endemism
patterns at the level of both species and minimum rank taxa (MRT; species
and infraspecific taxa). A total of 6,927 MRT are native to the CFP,
including 6,143 vascular plants and 784 bryophytes. Of these, 2,612
vascular plants are endemic to the CFP (42%) compared to 37 endemic
bryophytes (5%). Finally, 2,506 native CFP vascular plant MRT (41% of the
CFP flora) and 454 CFP bryophyte MRT (58% of the CFP flora) are found
outside California in the Oregon and Baja California parts of the CFP.
This high degree of sharing across political boundaries among both
vascular plants and bryophytes highlights the cohesiveness of the CFP, and
the need to focus more research effort on biotic regions.