Clarence Irving Seely (1912-2000) was a professor, consultant, and assistant research director working in the fields of agronomy and weed science. He was mostly active between 1935 and 1976. Prior to teaching, he worked for the US Department of Agriculture as one of the first investigators tasked with researching treatments to control perennial weeds during the late 1930s.

He graduated with honors from Washington State College in 1933. He was granted a master's degree in 1935. He served as superintendent at the Lind, Wash., Branch Experimental Station in 1934 and 1935 and then joined the USDA as Assistant Agronomist in weed investigations in 1936. Clarence was one of the original four "weed investigators" employed by the USDA as a result of the historic Bindweed Investigations Appropriation Bill of 1936.

He served as Assistant and Associate Agronomist and Director of the Genesee, Idaho, Bindweed Research Station until 1947, when he joined the Agronomy Department as Agronomist and Weed Scientist of the University of Idaho. In 1955, he joined the teaching staff at the university with the title of Agronomist and Professor of Agronomy and Weed Science. He retired as professor emeritus in 1976.