Larry was born on April 9, 1943, in Duluth, Minnesota, and was the oldest of four children. His parents operated a dairy farm and a trucking business.
Larry was an undergraduate at the University of Minnesota, Duluth from where he received a BA degree in botany with a minor in chemistry in 1965. Immediately after receiving his degree, he left for Mexico on a plant-collecting trip. In the fall of 1965, he entered graduate school at the University of Connecticut at Storrs, and in 1968 received an MS degree in botany by writing a thesis on the flowering plant genus Coriaria (Coriariaceae). For his thesis work Larry traveled and collected extensively in the Andes of South America. While at the University of Connecticut, he met Judith E. Troop, a fellow botany student, and they were married in 1968.
Larry applied for admittance to study horticultural plant taxonomy of the Gesneriaceae (African violet family) at the L. H. Bailey Hortorium at Cornell University. But in the meantime he was awarded a Horticultural Interchange Fellowship to study at the Royal Botanic Garden, Edinburgh, Scotland, which allowed him to visit several botanical gardens and herbaria in the United Kingdom and elsewhere in Europe from 1968 to 1969. Returning to Ithaca, New York, in late 1969, Larry resumed graduate study and undertook more fieldwork for his thesis research, especially in the Caribbean region. Larry completed his PhD degree in 1972 in plant taxonomy with a minor in entomology.
Both Larry and his wife interviewed for the same position in the biology department at George Mason University in Fairfax, Virginia. Judy got the position and they moved to Northern Virginia in August, 1972. Larry received a position as assistant editor on the Flora North America Program in the Department of Botany, Smithsonian Institution. That Program at the Smithsonian only lasted until April 1973, and then for six months Larry worked as a contractor at U.S. Department of Agriculture checking the names of the plants being investigated for anti-cancer research. In September 1973, a curatorial position in the Department of Botany at the Smithsonian became available, which was offered to and accepted by Larry. He continued his research on tropical plants, especially the Gesneriaceae at the Smithsonian.
Since 1973, he has undertaken fieldwork in several parts of the world, including India, Australia, New Zealand, China, and several times in Central and South America. He has been involved in several floristic and revisionary projects. From 1987 to 1992, Larry was chair of the Department of Botany, and continued as a curator and research scientist, and director of the Floristics Office in the Department until his retirement in 2003. Larry is a member, and has been an officer in several professional societies, including serving as a member of the board of directors of the International Association for Plant Taxonomy-USA, a fellow of the Linnean Society of London, secretary-treasurer of the Association for Tropical Biology (1981-85), secretary for the Organization for Flora Neotropica (1993-96) while serving on that Board, and vice president and president of the Botanical Society of Washington. He was honored by his alma mater for his scientific achievements by induction into the Academy of Science and Engineering in 2003.
Academically, Larry has advised several graduate students, was appointed as an adjunct professor in biology at George Mason University, and was an honorary professor of the Open Laboratory of Plant Systematics of the Institute of Botany, Chinese Academy of Sciences in Beijing. Larry and Judy have one son, Jeremy Owen, born in 1980.
Larry was elected to the Washington Biologists’ Field Club in 1982, and has been a member of the research committee, the board of managers, and since 1997 has been the Club’s archivist.