The correspondence files of the Arnold Arboretum include letters that were written and received by staff members from the 1880s to the 1960s. Most letters focus on plant accessions, plant exploration, plant identification, plant requests, and taxonomy. Correspondence from famous horticulturists affiliated with botanical gardens and arboreta, and from government agencies, and active gardeners and amateur horticulturists are represented. Any correspondent name or institution can be searched by first name, last name, affiliation, city, state, and country. The correspondence files are housed in separate locations within the archives, which include the Sargent LetterBooks, the Pre-1927 Letters, the Post-1927 Letters, and letters within specific Archival Collections.
The Sargent LetterBooks are nine bound volumes that contain letters written by Charles Sprague Sargent, the first Arnold Arboretum director from 1872-1927. The Pre-1927 files contain letters that were received by Arboretum staff members, primarily Charles Sprague Sargent. The Post-1927 files contain letters of Arboretum staff members including Alfred Rehder, John G. Jack, Hugh M. Raup, Joseph H. Faul, and William H. Judd. Correspondence from notables such as Liberty Hyde Bailey and from famous institutions like Royal Botanic Gardens Kew, London Royal Horticultural Society, and New York Botanical Garden is represented. In addition to letters written and received by staff members, the Archival Collections contain letters from staff members on international plant collecting expeditions, including Ernest Henry Wilson's letters from China.
"Did the people remember Dr. [Augustine] Henry? Did they know the K'ung-tung (local name of Davidia)? To these and similar questions they pleasantly answered in the affirmative. Would someone guide me to the tree? Certainly!" Recalling E. H. Wilson's search for the dove tree in China in 1899.