American physician, botanist, and forester. In 1860, entered the Lawrence Scientific School, Harvard University, where he was a student of, and an assistant to, Asa Gray. Enlisted in the 131st Pennsylvania Infantry in 1862; commissioned captain in the 20th Pennsylvania Cavalry in 1863; honourably discharged, 1864. Professor of botany, Pennsylvania State Agricultural College, 1867. Botanist and surgeon to the government survey in Colorado, New Mexico, and California, 1873. Professor of botany, University of Pennsylvania, 1877–1904.
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