First published in 1925, Willis Linn Jepson's Manual of the Flowering Plants of California has been a standard reference for teachers, students, and naturalists. Since that time, hundreds of new species have been identified and botanical investigation has become more sophisticated. Now Jepson's philosophy of making such information available to all is again realized in this new volume, which includes a wealth of material accumulated over the past decades. With contributions from two hundred botanists across North America, this is the most comprehensive resource and identification guide to nearly eight thousand varieties of native and naturalized California plants. The means to identify plants (using key traits and illustrations) is accompanied by special information such as horticultural requirements, endangerment, toxicity, weed status, and notes on the management of sensitive species. Identification keys have been designed for ease of use, and terms have been simplified and illustrated, making the new Manual the most authoritative field guide for the expert and amateur alike.