Creator
- Pepper, Claude D.1
- Peterson, Franklin M1
- Pfeiffer Family1
- Plant System 1
- Pleas, Charles Earl1
- Ponder, Clara M.1
- Ponder, Ernest Ayer, 1918-19981
- Price, Elsie Goldsby1
- Pyburn, Nita Katharine1
- Resler, Walter H.1
- Rifkin, Jack, 1922-20021
- Rios, William1
- Roach, Ulysses B. (Ulysses Bracy)1
- Roberts, Theodore1
- Rohrer, Jessie C. (1891-1987)1
- Rolfe, Walter, 1880-19441
- Rosales, Eustasio, approximately 1870-19371
- Roselle, Anne1
- Rosen, Mary Sue, 1944-1
- Rosen, Paul, 1938-1