Date of this Version
Thesis presented by Per Axel Rydberg for the degree of Master of Arts, University of Nebraska, June 1895.
Rydberg (1860–1931) was born Sweden and emigrated to the United States in 1882, first to mining camps in upper Michigan and eventually to Wahoo, in Saunders County, Nebraska, where he taught mathematics from 1884 to 1893 at now defunct Luther Academy. In the summers of 1891-1893, 1895, and 1896 he was a field agent for the United States Department of Agriculture and collected plants in Nebraska, South Dakota, Montana, Idaho, Wyoming, and Colorado, and specimens from those and other trips are in the Bessey Herbarium at the University of Nebraska–Lincoln, which house what is now known as the Charles E. Bessey Herbarium (NEB), founded about1872.
Rydberg enrolled at the university to study botany with Bessey, earning his first degree in 1891 and his M.A. in 1895. In 1898, he received his Ph.D. under Nathaniel Lord Britton at Columbia University in New York City. He became affiliated with the New York Botanical Garden and spent his remaining career there, eventually becoming its herbarium’s director.