American botanist. While considered a specialist in neotropical Rubiaceae, Dwyer's botanical interests were broad and he gave particular attention to Ochnaceae and Fabaceae (Leguminosae) earlier in his career. John Duncan Dwyer was born in Newark, New Jersey, and studied at Fordham University, where he gained his PhD in 1941 and began his research on tropical plants. He worked at several colleges in New York State in his early career and began a family in Albany, New York, having married Marie Rita Rozelle in 1942.

Dwyer began a long tenure at St Louis University in 1953, where he was appointed chair of the biology department. The following year, he took up his first post at Missouri Botanical Garden as a research associate. Dwyer's interest in tropical plants, especially those of Panama, led him on many voyages.

Dwyer made more than 20 expeditions to Panama in the 1960s, collecting about 6,000 numbers from difficult to reach areas thanks to help from the US Air Force. The trips resulted in a treatment of the Fabaceae for the Flora of Panama. With Tom Croat and Al Gentry he ventured to Belize on a National Geographic sponsored exploration of the Maya Mountains and prepared a checklist of the country's plants with his student, David Spellman. He collected in all the other Central American countries over the years as well as in South America and Saudi Arabia. He particularly studied plants with medical or industrial potential and his key specialisation came to be the Rubiaceae, on which he worked with his student, Victoria Hayden, and with David Lorence.

Skilled in Latin, Dwyer often helped others with botanical language and was instrumental in many useful developments at St Louis University such as instigating the medical botany (later ethnobotany) course in conjunction with Walter Lewis at Washington University. His awe-inspiring knowledge of tropical plants impressed students and colleagues alike on field trips and in the herbarium, and Dwyer was also called on locally by coroners and hospitals for his knowledge of toxic plants. When cases of suspicious deaths arose, the botanist would look at samples of stomach contents and was always looking for better ways to preserve refrigerated and dried evidence.

Retiring from St Louis University in 1985, Dwyer became Professor Emeritus and carried on working on a revision of Hoffmannia even after he moved into a retirement home. He served as president of the Missouri Academy of Science and was elected a Fellow of the Linnean Society in 1984. He is honoured by the 'John Dwyer Public Lecture in Biology' series at St Louis University and the Missouri Botanical Garden, funded by a family bequest.

Sources:
T.B. Croat, W.H. Lewis and P. Bernhardt, 2006, "John D. Dwyer (1915-2005)", Taxon, 55(2): 543-544.