Chardon, Carlos E. (1954, 1 letter) University of Chicago (1952, 1 letter) Chickering, Allen L. (1949, 1 letter) Chidsey, Jane L. (1956, 1 letter) Chouard, P. (1954, 2 letters) The Chronica Botanica Co. (1957, 1 letter) Cisler, Mrs. Elsie W. (1953, 2 letters) Clark, William G. (1958, 2 letters) Clary, Mrs. Ruth (1957, 2 letters) Clausen, Dr. Roy E. (1924–1955, 7 letters) Clayton, Dr. E.E. (1949–1954, 5 letters) Cobb, Mrs. Percy W. (1949, 1 letter) Colligan, Dr. Francis J. (1948, 1 letter) Colwell, Dr. W. E. (1948, 2 letters) Compton, Mrs. (1958, 1 letter) Condit, Dr. Ira J. (1950–1954, 4 letters) Coney, Donald (1950–1952, 2 letters) Conservatoire et Jardin botaniques (1939–1956, 31 letters) Constance, Dr. Lincoln (1947–1957, 33 letters) Cook, Howard S. (1949, 2 letters) Coolidge, Dr. Harold J. (1949–1956, 2 letters) Copeland, Gloria L. (1956, 1 letter) Copeland, H.F. (1932, 1 letter) Coppinger, Henry (1951, 2 letters)