Gardener and scientist Alfred Rehder immigrated from Germany to the United States in 1898 to study American trees and shrubs at the Arnold Arboretum for the summer. He intended to return to Germany in the autumn, but by chance he stayed. One year later, Charles Sprague Sargent, director of the Arboretum, hired Rehder for the task of compiling a bibliography about woody plants up to the year 1900. Rehder accepted the massive assignment, which eventually grew to a five-volume, 3,789-page work known as the Bradley Bibliography. To be sure his list was exhaustive, Rehder consulted every botanical library collection in the eastern United States and traveled twice to Europe to visit libraries there. Rehder himself physically examined all but five percent of the more than 100,000 entries in the bibliography.
In 1918, Rehder was promoted to the position of curator of the herbarium at the Arnold Arboretum. During his career there, he established the Journal of the Arnold Arboretum and served as its editor for twenty-two years. He also wrote for the journal, contributing over a hundred pieces for publication. Among his other accomplishments, Rehder established the first system of isothermic zones for the United States that demonstrated how the severity of winters correlated to the hardiness of plants. He also edited and authored a number of other publications including the Manual of Cultivated Trees and Shrubs (1934) and a Bibliography of Cultivated Trees and Shrubs (1946). Rehder officially retired in 1940 at the age of 77 but continued to work until his death in July, 1949.
References:
“Alfred Rehder (1863-1949) papers, 1898-1940.” 2012. Finding aid at the Archives of the Arnold Arboretum of Harvard University. Accessed August 1, 2014. http://arboretum.harvard.edu/wp-content/uploads/II_A_2_AR_2012.pdf
Pearson, Lisa. “Alfred Rehder, the Bradley Bibliography and BHL, oh my!” The Arnold Arboretum. Last modified September 30, 2013. http://arboretum.harvard.edu/alfred-rehder-the-bradley-bibliography/
“Professor Alfred Rehder’s Retirement.” Arnold Arboretum Bulletin of Popular Information 11 (October 25, 1940): 57-58. http://arnoldia.arboretum.harvard.edu/pdf/articles/1940-8--professor-alfred-rehder-s-retirement.pdf