Researchers conducting genetic and ecological studies deposit voucher specimens in the herbarium, thus providing permanent documentation of the species involved in that work. An herbarium is an integral part of teaching and research programs in the plant sciences, ecology and related fields of agriculture. Many colleges and most universities maintain an herbarium collection, as do many botanical gardens and natural history museums. Researchers from different herbaria interact through specimen exchange and loans, as well as through visits among the institutions.
USD's Herbarium (acronym: SDU) holdings include between 20,000-30,000 specimens, specializing in collections from South Dakota; upper midwestern U.S.; eastern Great Plains. Important collections: F. L. Bennett, W. H. Over, J. F. Brenckle, S. S. Visher, A. C. McIntosh.