by Arthur Vance Swarthout, Charles Sidney Leete, David Griffiths, David Segrid Olson, Elmer Lash, Ernst H. Wiecking, Frank Getz Ashbrook, Frank Heidtman Lathrop, Frederick Charles Lincoln, George Emil Heck, George Herbert Coons, H. F. Willard, Harold Coleman Hallock, John Chambers McDowell, Justus Watson Folsom, M. A. Yothers, R. W. Leukel, Ralph Henry Elsworth, Reginald D. Forbes, United States. Department of Agriculture, Walter Cochran Davis, Wiley Croom Smith, William Gustavus Wahlenberg, Charles M. Harris, Dewey Stewart, Donald Bruce, Fletcher Pearre Veitch, Floyd Frank Bondy, Ira Burton Lanphier, Karl Burchard Hanson, Theodore Lemuel Bissell, William Melvin Mohler, Finley George Larmer

1929

by Charles Adolph Weigel, Charles John Stauber, D. C. Parman, D. W. Jones, David Griffiths, Don Inskeep Skidmore, Elmer Ottis Wooton, Erastus Newton Bates, Ernst H. Wiecking, James A. Holden, John Chambers McDowell, John Clay Overpeck, Kelsey Beeler Gardner, Lloyd Stanley Tenny, Lucia McCulloch, Madge Janet Reese, Ora Stanley Fisher, Orator Fuller Cook, Raphael Zon, United States. Department of Agriculture, Ward Shepard, William Alfred Schoenfeld, William Edward Wintermeyer, D. J. Caffrey, Duncan Stuart, George P. Bodnar, William Norwood Sparhawk, R. R. Graves

1927