Floristic Definition of Southern California

In popular culture in California, southern California refers only to Los Angeles and San Diego counties, usually the coastal parts of Riverside and San Bernardino counties, and sometimes goes as far north as the city of Santa Barbara. Technically, the desert portions of Riverside and San Bernardino counties, along with Imperial County, are in southern California, and the Wikipedia article on southern California includes them. But most people will agree that culturally those desert sections are very different than the coastal section. When someone in New York City thinks of southern California, they are thinking of Los Angeles, not Salton City or El Centro.

Whether the desert regions or included or not, this is very different from the logical view that everything south of the geographic latitudinal midpoint of California should be called southern California. By that logical view, the city of Santa Cruz, and the southern parts of the city of San Jose, are in southern California, since they have latitudes below 37.3°. (California ranges from an average of about 32.6° on its southern border to 42° on its northern border.) But expressing that viewpoint up there might get you killed!

In particular, as far as I know, no one in Kern County or the Sierra Nevada considers themselves to be in southern California, and most are decidedly proud that they are not in southern California. (;-)

Note that logic rarely rules for the names of similar parts of the country. Two examples: The Midwest of the United States is actually the north-central part of the country. North San Diego County extends to the southern half of the county, but only includes the extreme westernmost portion of northern San Diego County.

The floristic definition of southern California is almost exactly the same for the coastal portion, but also includes the desert portions of California. (Maybe culture and biology are indeed both driven by geography!)

Here is the definition as used by Munz (1974) in his Flora of southern California:

The area designated as southern California in this book extends from its northern boundary of Point Conception, Santa Barbara County, eastward along the crest of the Santa Ynez Mountains to the Mt. Pinos region in Ventura County, Fort Tejon in Kern County, the Techachapi and Piute mountains, then northward to Little Lake in Inyo County and along the east slopes of the Inyo and White Mountains to the Deep Springs Region. It does not cover the northern part of Santa Barbara County, the southern end of the San Joaquin Valley, nor any of the Owens Valley, since each of those areas includes many elements of a more northern flora.

As here defined, southern California comprises a cismontane area between the sea and the mountains, a montane area which in some cases reaches considerable elevation, and a transmontane or desert area which is constituted largely of the Mojave and Colorado deserts. A fourth area consists of the islands off the coast: a northern group or Channel Islands (San Miguel, Santa Rosa, Santa Cruz and Anacapa islands) and a southern group (Santa Catalina, San Clemente, Santa Barbara and San Nicolas islands).

Using the Jepson Manual floristic regions, this is essentially the same as saying southern California = SW + D. The areas to the north of southern California are Central Coast, Great Valley, and Sierra Nevada.

Go to Introduction to Native and Introduced Plants of Southern California

Copyright © 2007 by Tom Chester and Jane Strong.
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Last Update: 14 August 2007.