by Edward C. Peck, Arthur Koehler, Charles Walter Collins, David Edmund Stephens, Ernest Bateman, George William Trayer, Hazel Katherine Stiebeling, Herbert Dwight Smith, James Edward McMurtrey, John Guice Sutton, John William Roberts, Joseph Clarence Silver, Joshua John Skinner, Mark Hughlin Haller, Milton Henry Fohrman, R. D. Garver, R. W. Leukel, Ralph Lester Miller, Raymond Secord Washburn, T. D. Jarrell, Thompson Elwyn Woodward, Walter M. Osborn, William Henry Fry, William Jasper Spillman, William John Nolan, Willis James Nolan, Carrington Bonsor Williams, Hazel Edith Munsell, Henry Morris Wanser, Ione P. Bassett, James Geere Dickson, James McKenzie Hankins, John Brown Cuno, John Clymer Dunegan, John Holmes Martin, John Robert Magness, R. R. Graves, Samuel Frederick Potts, Aaron Francis Bracken, Aaron Guy Johnson, Fletcher Pearre Veitch, Harvey Blount Mann, William Walter Yothers

1932

by Charles A. Fort, Charles Chase Hill, David Francis Costello, David Irving Blumenstock, Doys Andrew Shorb, Elmer R. Roth, Ethelbert Lee Langsford, Everett Elmer Wehr, Frank M. Eaton, Horace Preston Lanchester, Irvin Carl Feustel, Leander D. Howell, Lucy Maclay Alexander, Lyle Thomas Alexander, Mark Hughlin Haller, Milton Henry Fohrman, Robert Edgar Worthington, Roy Hyer Canfield, Stafford Coleman Happ, Thomas Randall Carson Wilson, United States. Bureau of Plant Industry, Vernon Webster Johnson, William Gustavus Wahlenberg, Bailey Sleeth, Ben Hur Thibodeaux, Gordon Rittenhouse, Horace Greeley Byers, John Stuart Pinckney, L. V. Wilcox, Nancy Griswold Clark, Nelson McKaig, Paul Lewis Harding, R. R. Graves, Raymond Price, Sidney Henderson, Smith Winford Greene, Edgar John Udine, Gilbert Colfax Dobson, Glen Edgington, Hiram Richard Reed, James Hayes Marshall

1940