Calflora A website that contains photos of nearly every species and subspecies of plant found in California.
California Herps A guide to the reptiles and amphibians of California.
These books are great references to learn about the natural history of southern California:
Oscar F. Clarke, Danielle Svehla, Greg Ballmer, and Arlee Montalvo. 2007. Flora of the Santa Ana River and Environs, with References to World Botany. Berkeley, CA. Heydey Books.[pruchase from CNPS]
Peter R. Dallman. 1998. Plant life in the World's Mediterranean Climates. University of California Press. Berkeley, CA. [purchase from CNPS]
Phyllis M. Faber. Common Wetland Plants of Coastal California. 1996. Pickleweed Press. Berkeley, CA. [purchase from CNPS]
Phyllis M. Faber and Robert Holland. 1996. Common Riparian Plants of California. Pickleweed Press. Berkeley, CA. [purchase from CNPS]
Joe Linton. 2005. Down by the Los Angeles River. Wilderness Press. Berkeley, CA.
Philip W. Rundell and Robert Gustafson. 2005. Introduction to the Plant Life of Southern California: Coast to Foothills. California Natural History Guides. University of California Press.