Rudolf Mathias Schuster was a German-born American botanist and hepaticologist. He was born on 8 April 1921 in Altmühldorf, Bavaria, Germany, and emigrated with his family to the United States as a child. He studied at Cornell University and later obtained a Ph.D. in entomology from the University of Minnesota in 1948, while already developing a strong interest in bryophytes.
After holding academic positions at the University of Mississippi, Duke University and the University of Michigan, Schuster joined the University of Massachusetts Amherst in 1957, where he became Professor of Botany in 1958 and remained until his retirement in 1983.
His research focused mainly on the taxonomy, morphology, evolution and biogeography of liverworts and hornworts. Over nearly six decades of fieldwork, he collected extensively in North and South America, Greenland, the Pacific region and other parts of the world. His herbarium comprises more than 80,000 specimens and is now housed at the Field Museum in Chicago.
R. M. Schuster described a large number of new taxa, including 455 taxa at species rank or below, 97 genera and 75 higher taxa. He also developed a widely used classification of liverworts and contributed substantially to the study of their biogeography, particularly in the Southern Hemisphere.
His best-known publication is the six-volume The Hepaticae and Anthocerotae of North America (1966–1992), which covers almost 6,000 pages and includes extensive treatments of morphology, anatomy and taxonomy. He later published three volumes of Austral Hepaticae, a planned synthesis of his studies of Southern Hemisphere liverworts that remained incomplete.
His wife, Olga Schuster, a professional editor, assisted him extensively in the preparation of his publications, typing and retyping manuscripts, commenting on the texts, and helping to prepare them for publication.
R. M. Schuster received two Guggenheim Fellowships, a Fulbright grant for research in New Zealand, and the Engler Medal in Silver from the International Association for Plant Taxonomy in 1992.
