American agrostologist and botanist from Hanover, New Hampshire who trained graduated from Dartmouth College (1936) and made local plant collections (1936-1938). Alan Beetle gained his Master's degree from the University of Wyoming (1938) based on a study of Scirpus, originally suggested by M.L. Fernald at the Gray Herbarium and the start of a long series of specialist papers on Cyperaceae. Beetle collected in South America (1938-1939) for the world fairs in San Francisco and New York and published on the phytogeography of Patagonia. Duplicate material from this expedition is at BM. He gained his PhD from the University of California, Berkeley, and joined the botany department (1940-1946) as an agronomist.

Beetle returned to the University of Wyoming at Laramie (1946-1976) where he taught and developed the Department of Rangeland Ecology and Watershed Management (WYAC) and made his later collections. He also worked on a revision of the genus Artemisia with K.L. Johnson. He was an active member of the Society for Range Management and a founder of the local chapter of the Audubon Society. After retirement he acted as an adviser on agronomy to the Mexican government and published a multi-volume account of Mexican grasses. He was a professor emeritus at the University of Wyoming, College of Agriculture where his important grass collection of over 10,00 specimens was deposited at WYAC, and the herbarium renamed the Alan A. Beetle Herbarium in his honour.