Instructor algae Chesapeake Biological Laboratory, 1941. Theresa Seessel research fellow Yale, 1941-1942. Plant physiologist Texas Agricultural Experiment Station, Beaumont, 1942-1945.
Assistant professor of University Notre Dame, 1945-1947. Senior scientist Argonne National Laboratory, 1947-1948. Associate professor Washington State University, 1948-1953.
Chairman botany department, 1949-1955, professor, 1953-1980. Guest professor Botanische Institute Technische Hochschule Darmstadt, West Germany, 1975. United States Senior Scientist Humboldt award, Darmstadt, West Germany, 1977-1978.
Fulbright research scholar, Australia, 1963.
Fellow of the American Association for the Advancement of Science. Member Biophysics Society, Botanical Society American, American Society Plant Physiologists (chairman Western section 1957-1958), American Bryological Society, American Association University Professors, N.W. Science Association (councillor 1952-1955), Sigma Xi. Member editorial board Plant Physiology, 1967-1970, 72-74, editor, 1974-1980.