The Desert and Other Transmontane Plant Communities of Southern California

Abstract

Transmontane southern California, less than one-quarter of the state's area, has a rich, specialized flora and vegetation due to most varied topography, substrata, and climate. Of the perhaps 5075 species in 145 vascular plant (129 angiospermous) families indigenous in California more than 2100 species in 123 families, more than two-fifths of the state's flora, are represented in transmontane southern California. About 935 species, of which 868 are in the south, 180 of the state's 880 indigenous genera, and 18 families are exclusively or effectively transmontane. A table lists the number of indigenous species of various transmontane ranges and other areas. Numerous, diverse habitats have led to the recognition of 32 different plant communities and 10 subcommunities, or 42 of the 88 recognized for the state by the author. A table lists the communities arranged in a hierarchy according to decreasing altitude from alpine through subalpine, montane, and transition to desert and alkaline scrub communities. These are each discussed briefly with comments on distribution, dominant or otherwise characteristic plants, and outstanding environmental features of the habitats occupied. Many communities are illustrated.