by Edgar John Udine, Edmund Lambert, Edward Mackay Chace, Emil George Boerner, F. L. Duley, Franklin Arthur Coffman, George Emil Gaus, Gerard Dikmans, Harold Robert Hochmuth, John Stuart Pinckney, Joseph Benjamin Shepherd, M. A. Yothers, Mark Hughlin Haller, Robert Hale Nelson, Roland McKee, Russell Rutherford Whitten, United States. Department of Agriculture, Victor Leo Stedronsky, W. A. Douglas, W. G. Bradley, William John Reid, William Solomon Porte, Carroll Clayton Cassil, Charles Scott Shaw, Dean Humboldt Rose, Earl Raymond Franklin, Harry August Schoth, Harry Bruce Walker, Latimer Ludwig Kelly, Paul B. Allen, Rhea Emerson Stitt, Thomas Laffin Baggette, Thompson Elwyn Woodward, William Alexander Noel, Arvid John Johnson, Marion Clawson, Paul Lewis Harding, Vinnie Arah Pease, Waldo Harold Kliever

1941

by Axel Langvad Andersen, Betty B. Peterkin, Charles Edwin Burkhead, Gerald J. King, Joseph Henry Stoeckeler, Walter H. Wischmeier, Dwight David Smith, Paul E Slabaugh, Robert Harold Miller

1965