Botanical correspondence during his affiliation with the Academy, first as a Jessup Student and later as Curator of the herbarium and head of the Botany department. Covers his varied interests in administering the department and as a member of National committees, representing the Academy, and matters pertaining to his special research with the “Scrophulariaceae.” A large block of the letters deals with the history of American botany and biography of botanists. Throughout his years here, he was active in the Philadelphia Boranical Society and for many years before his death he carried the title of professor of the University of Pennsylvania and was also editor of the botanical section of Biological Abstracts. Some correspondence was maintained as a member of the Ludwick Institute and a small amount in this collection points to his active attachment to the Friends Society locally. A few are addressed to earlier Curators.