the origin of the Cordilleran flora, a region bounded by the east slope of the Sierra Nevada and Transverse Ranges and Peninsular Ranges of California to the eastern front of the Rocky Mountains, north to the Snake River Plain-western Wyoming, and south to central Arizona-New Mexico. In 1996 Raven, Axelrod, and Al-Shehbaz wrote a paper on the history of the modern flora of China, Europe, and the continental United States. They said that the three regions have approximately the same geographic area, yet China has two times the number of species as the United States, and three times as many as Europe. They asserted that all three regions had essentially the same flora as of 15 million years ago, but China came to possess the most species because of three reasons. First, China has a tropical rain forest. Second, there is an unbroken gradient of vegetation from the tropical rain forest to "boreal coniferous forests that has persisted and afforded habitats characterized by equable climates during the last 15 million years, when massive extinctions were taking place elsewhere in the Northern Hemisphere...such continuity is interrupted in North America by the Gulf of Mexico and in Europe by the Alps, the Mediterranean, and the Sahara Desert." The third reason was due to the impact of the Indian subcontinent with Asia starting 50 million years ago, making a "highly dissected, elevated geography." Taxonomy/Systematics/Floras Raven has produced a wide variety of works in the area of plant systematics. Most of them are related to the plant family Onagraceae. In 1969 he published a 235-page report on Camissonia; In 1976 he, along with his wife at the time Tamara Engelhorn, published a 321-page monograph on Epilobium in Australasia; an embryological analysis of species in the Myrtales; In 1992 a 209-page monograph on the systematics of Epilobium in China; in 1997 a 234-page monograph on the systematics of Oenothera; and in 2007 a 240-page monograph on a reclassification of the Onagraceae. And in 1981 he published a 1,049 page monograph on the systematics of Legumes. He has also published a number of books (Floras) devoted to the systematics of plants found in particular regions. These include a 1966 book on the native shrubs of Southern California; a 1966 flora on the Santa Monica Mountains in California; and, with various editors and authors, an ongoing 33 volume set (to date) on the flora of China, organized