Career
He was Professor of Botany (1937-1955) and director of the Morris Arboretum (1939-1954) at the University of Pennsylvania, and previously taught at Washington University and Cornell. Following his retirement from Pennsylvania he was appointed Research Scholar of Botany at Indiana University. He helped found the abstracting journal Botanical Abstracts, and served as editor-in-chief of it and of its successor, Biological Abstracts.
