This proposal examines the history of botany in the U.S. during the period before, during and immediately after the evolutionary synthesis. It is organized around the scientific career of G. Ledyard Stebbins, Jr., one of the nation's foremost botanists, geneticists and evolutionists. Much of what is known about the evolutionary synthesis has taken the perspective of zoology, and has examined the contributions of zoologists. Little is known of the work of botanists and how they contributed to our understanding of evolutionary processes. Even less is known about the history of botany in the U.S. during the middle decades of this century, a period that saw unsurpassed growth in science and a vast restructuring of the plant sciences. The main goals of this project are to assess the contributions of key botanists to the evolutionary synthesis, to redress the imbalance in the historiography of the synthesis, which favors animal models over plant research, and to understand an important period in U.S. botany. The project will culminate in a scholarly book and three articles, one of which will appear in a volume of scientific papers of Stebbins that the PI will jointly edit.