Nelson was born at Sugar Creek, in Lee County, Iowa to parents Christen Nelson and Anne (Evenson) Nelson, who had immigrated from Norway. Aven was the youngest of four children in a Quaker family. He attended Kirksville State Normal School in Kirksville, Missouri from which he was graduated in 1883 with his Bachelor of Arts degree, while in 1887 he received the M. S. D. degree. He further continued his education in Drury College at Springfield, Missouri, which conferred upon him a Master of Science degree in 1890. He next entered Harvard University was awarded the Master of Arts degree in 1892.
In 1893, he co-founded the Rocky Mountain Herbarium.[3][4]
At that time he started to curate and edit large duplicate series of herbarium specimens with printed labels and fixed titles, among others Plants of Wyoming. From the Rocky Mountain Herbarium and Plants of Yellowstone National Park. From the Rocky Mountain Herbarium.[5][6][7] These large and widely distributed collections are sometimes confused with exsiccata works.
In 1885, he married Celia Alice Calhoun (1860-1929). They were the parents of two children. In 1931, he married fellow botanist Ruth Elizabeth Ashton (1896-1987) in Santa Fe, New Mexico.[11] He died in Colorado Springs, Colorado in 1952. The Aven Nelson Memorial Building on the campus of the University of Wyoming is named in his honor.[12]
This article incorporates text from this source, which is in the public domain: Bartlett, Ichabod Sargent (1918). "Professor Aven Nelson". History of Wyoming. (S. J. Clarke Publishing Company). pp. 588–589.