This collection consists mainly of correspondence related to Allen’s career and other positions he held. None of this correspondence was written during the UFC banana-collecting expedition to Southeast Asia, but letters of the previous and following periods make briefly references to it. Included are references to Allen’s collection of Central American orchids, palms and other plants; his work on orchids for publications; the botanical art of his wife, Dorothy Osdieck Allen (1911–1973); difficulties he encountered due to his lack of a college degree; his magnum opus, The Rain Forests of Golfo Dulce (Gainesville, University of Florida Press, 1956); and the activities and publications of other botanists, particularly his correspondents. This collection also contains the manuscript of Allen’s The Rain Forests of Golfo Dulce (Stanford, Calif., Stanford University Press, 1977, reissue of 1956 edition) as well as letters (1956–1958) from recipients of the book and copies of reviews, his Orchidaceae manuscript for the Flora of Panama (Annals of the Missouri Botanical Garden, 1949, vol. 36, nos. 1–2; reprinted as Orchids of Panama, Monographs in Systematic Botany, vol. 4, 1980) and “An Annotated Checklist of Known Orchids of Panama, Together with Some Introductory Remarks Regarding Their Distribution and Relationships” (with 41 plates by Dorothy Allen); and photographs, notes and other items relating to Allen’s “Conquest of Cerro Santa Barbara” (Ceiba, 1955, 4: 5). There is also miscellaneous correspondence of Allen, his wife, colleagues and friends related to his botanical work and the publication of research or articles pending at the time of his death. Photographs also are part of this collection, including ones by Allen received from Walter Henricks Hodge and added to this collection in 2018.