The culmination of more than twenty-five years of research in this magnificent desert and delta by botanist Richard Felger. This comprehensive floristic study of more than 565 species of vascular plants features original diagnostic descriptions and innovative identification keys to the families, genera, and species. Particular attention has been devoted to taxa that are poorly known. Even weeds and their histories are treated in detail. Hundreds of illustrations by such eminent botanical artists as Lucretia Brezeale Hamilton, Matt Johnson, and Bobbi Angell will aid in the identification of plants. Common names of plants are given in English, Spanish, and O'odham.