In this culmination of a distinguished career in natural history, Clarke (who established the Herbarium at the U. of California, Riverside) headed a team that documented the botanical diversity of this major southern California waterway. The guide includes an introduction to plant ecology, a list of all known species in the Santa Ana River Watershed, map, identification keys, family tree of major plant groups, a world plant phylogeny, color and b&w illustrations, and a glossary. Annotation ©2007 Book News, Inc., Portland, OR (booknews.com)