- Reginald D. Forbes, Alvah Peterson, Arthur Truman Semple, Charles Dwight Marsh, Clarence Luther Forsling, Donald Bruce, Edmund Cecil Shorey, Franklin Post Metcalf, Hugh Curtis McPhee, Irvin Carl Feustel, Joshua John Skinner, Josiah Chase Folsom, Karl S. Quisenberry, Lyle Thomas Alexander, Marinus Westveld, R. W. Leukel, Richard Edwin McArdle, Stuart Bevier Show, Theo. H. Scheffer, Thomas Roy Truax, Walter Carter, Wilbur Clifford Edmundson, William Henry Black, A. B. Clawson, E. I. Kotok, Edwin Alfonso Trowbridge, H. E. Dvorachek, Horace Greeley Byers, K. D. Jacob, K. F. Warner, Lester Henry Reineke, O. N. Eaton, Charles Vinyard Wilson
· 1931
- 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
- Arthur Henry Joel, Charles Calvert Smoot, Charles Knesal Cooperrider, Clarence Sheldon Slater, Cyril Oliver Bratley, Eugenia Cuvillier, George Henry Hepting, George Luther Schnur, George W. Barber, George Wallace Musgrave, Harold Blaisdell Shepard, Herbert George Barott, James Stewart Wiant, James William Park, Lawrence Zeleny, Lewis Bertie Olmstead, Margaret Blanche Hays, Norman Julian Wall, Paul Lewis Harding, R. L. Piemeisel, R. W. Leukel, Stephen Harold Hastings, Stuart Bevier Show, William Henry Black, Barnard Andrew Hendricks, Dan Hansen, David Augustus Coleman, E. I. Kotok, Edwin Alfonso Trowbridge, F. F. Dicke, Francis Raymond Lawson, George Grant Hedgcock, Jacob Martin Lutz, Oscar Roland Mathews, R. S. Holmes, Ralph Wylie Frey, Robert Arthur Norton, J. I. Hardy, Dean Humboldt Rose, Horace Greeley Byers
· 1937
- Alfred Douglas Edgar, Alpha Cornelius Johnson, Charles Brooks, D. E. Fox, Dwight Moore DeLong, Ernest Wilson Grove, George Whitfield Delux Hamlett, Horace Greeley Byers, Irvin Cecil Brown, Jacob Martin Lutz, James Edward McMurtrey, James Merrill Wallace, James Stewart Wiant, John Carl Thysell, Knute Bjorka, Leander D. Howell, Ralph Edwin Beckett, Ross Calvin Thompson, Stephen Harold Hastings, T. D. Jarrell, Theo. H. Scheffer, Thompson Elwyn Woodward, William Henry Black, Albert Marion Murphy, George Grover Becker, James McKenzie Hankins, James Richard Quesenberry, Joseph Benjamin Shepherd, Lacy Porter McColloch, Leonard Joseph Watson, Robert S. Stitt, Samuel Benton Nuckols, Alfred Leroy Baker, Edward Neal Duncan, Fletcher Pearre Veitch, Lionel Harris, Lon Adrian Hawkins
· 1939
- Alfred Paul Dachnowski-Stokes, C. C. Plummer, Charles Roy Adair, Fisk Gerhardt, George Jacob Hough, H. S. Haller, Hardy Lomax Shirley, Irvine Theodore Haig, Jasper E. Pallesen, Kenneth Thurman Williams, Leander D. Howell, Myron Francis Babb, Nelson McKaig, O. N. Eaton, Paul A. Woke, Paul Lewis Harding, Philip B. Dowden, Preston Richards, Raymond Carl Rietz, Robert Claude Wright, Robert Leslie Shotwell, Samuel Ebb Crumb, W. P. Green, Winn Frederick Finner, Boyce D. Ezell, C. J. Babcock, H. H. Laude, Hubert William Lakin, John Robinson Winston, Kenneth Pickett Davis, Lewis Alexander Hurst, M. McPhail, Paul M. Eide, Philip Lindsey Gile, Ronald Lester Mighell, William Virgil Hukill, Alfred Eric Bonn, D. F. Fisher, Dean Humboldt Rose, F. M. Grant, Horace Greeley Byers, J. W. Monk, Robert H. Weidman, Zera Calvin Foster
· 1941
- Ralph U. Cotter, C. A. Magoon, Charles Brooks, Charles Faye Sarle, Charles Otis Johnston, Curtis Paul Clausen, Elmer Ottis Wooton, Floyd Franklin Smith, Fred W. Miller, Harvey Leroy Westover, Howard E. Middleton, Irvin Cecil Brown, Irvine Theodore Haig, James Thorp, Lester Henry Reineke, Lyle Thomas Alexander, Millard Peck, Orator Fuller Cook, Ronald Floyd Luxford, Samuel Augustus Jones, V. L. Wildermuth, Walter Chapin Holmes, William Hobson Rowe, William John Nolan, Willis James Nolan, Bernard Frank, Charles W. Culpepper, Clarence Sheldon Slater, Donald Bruce, Edwin Butterworth Mains, Elmer Valentine Walter, Horace Greeley Byers, John Thomas Scanlan, Johnson Thatcher Sarvis, Lorraine Joseph Markwardt, Paul A. Berry, R. R. Graves, Theodore Roosevelt Gardner, Anis Rae Peterson, Kaku Sato, Leroy Moomaw, Paul Axel Clarence Eke, George W. Morgan, John Carl Thysell, M. A. Bell
· 1932