User:Edward Cobb

Robert Theodore Clausen (1911-1981)

Robert Theodore Clausen was born in New York City. Although interested in both natural history and zoology, Karl M. Wiegand was able to influence Clausen and move him towards botany and taxonomy. Clausen’s early published works were concerning ferns. He obtained his degrees at Cornell University, AB in 1933, a MS ‘Botrychium of Northeast North America’in1934 and PhD ‘A monograph of the Ophioglossaceae’in 1937.

He met fellow botanist, Edna Rublee at Cornell and they were married in 1942. Edna Rublee obtained her MS degree in Botany at Cornell in 1943. Her thesis was “Medicinal Plants of New York State”.

Clausen was employed by the Bailey Hortorium as a graduate student in 1935, he was first an instructor (1937-1939) and then as an assistant professor of botany (1939-1941). In 1941 he joined the Botany department, where he became an associate professor in 1944 and professor in 1949. He also became curator of the Wiegand Herberium in 1954. In 1974 Clausen was awarded the Chancellor’s Award for excellence in teaching from the State University of New York. Upon his retirement in 1977, he was awarded emeritus status.

He devoted much of his research to the genus Sedum, which he pronounced sedum not seedum. He wrote three books on Sedums, ‘Sedum of the Trans-Mexican Belt: an exposition of taxonomic methods” in 1959 and ‘Sedum of North America north of the Mexican Plateau’ in 1975. Both of these volumes were illustrated by Ithaca artist Elfriede Abbe. His book, ‘Variation of species of Sedum of the Mexican Cordilleran Plateau’ was published in the year of his death.

Clausen was passionate about plants and inspired many students to seek professional careers in botany. He led vigorous field trips for his classes during the week. He took students to exciting natural habitats in the Ithaca area including McLean Bog, Fall Creek Natural Areas and South Hill Swamp. Clausen is remembered by his students for the “optional” Sunday taxonomic field trips in the Ithaca area. Most students dared not miss attending these vigorous all day outings. When part of South Hill Swamp was up for sale, Clausen purchased the property and later had ownership transferred to Cornell University.

Clausen had seven PhD students finish their degrees and he had twelve MS students, his last two graduate students obtained MS degrees in 1977. Although ill for more than two decades, he continued to collect herbarium samples and annotate specimens to his last days.

R.T. Clausen, 1949. Checklist of the Vascular plants of the Cayuga Quadrangle. Cornell Agricultural Experiment Station, Ithaca, NY.

R.T. Clausen, 1959. Sedum of the trans-Mexican volcanic belt: an exposition of taxonomic methods. (Drawings by Elfreide Abbe) Comstock Pub. Associates, Ithaca, NY.

R.T. Clausen, 1975, Sedum of North America north of the Mexican plateau. (Drawings by Elfriede Abbe) Cornell University Press, Ithaca, NY.