Robert T. Clausen
(1911 - 1981)


Robert Theodore Clausen was a dedicated teacher and plant taxonomist. He travelled throughout the U.S. and Mexico researching the abundant genus, Sedum (Crassulaceae). He was also the Curator of Cornell's Wiegand Herbarium for 23 years.


The Cornell Connection: Clausen worked for the L. H. Bailey Hortorium as an instructor (1937-1939) and Assistant Professor of Botany (1939-1941). In 1941 Clausen joined the Department of Botany and rose to the rank of Associate Professor (1944) and Professor (1949). Clausen was also appointed Curator of the Wiegand Herbarium in 1954.


Robert T. Clausen was born on December 26, 1911 in New York City, NY. He attended Cornell University where he received his bachelor's degree in 1933, his master's degree in 1934, and his doctorate in 1937. Clausen worked as an instructor for the L. H. Bailey Hortorium from 1937-1939. He then became an Assistant Professor of Botany in the Hortorium from 1939-1941. It was in 1941 that Clausen joined the Department of Botany and rose to the rank of Associate Professor in 1944 and Professor in 1949. In addition to Professor, Clausen was also appointed Curator of the Wiegand Herbarium in 1954. Emeritus status followed his retirement in 1977.

Although having studied other plants, Professor Clausen's main research was on Sedum (Crassulaceae). He published two major works on Sedum. The first was Sedum of the Trans-Mexican Volcanic Belt: An Exposition of Taxonomic Methods, published in 1959. The second was Sedum of North America North of the Mexican Plateau, published in 1975. The study of Sedum took him throughout the United States, Canada, Mexico, and Central America.

In addition to his taxonomic research, R. T. Clausen was also an excellent teacher. In 1974 he received the Chancellor's Award for Excellence in Teaching from the State University of New York. His additional duties of curating the Wiegand Herbarium complemented his field work. Following his retirement in 1977, the Wiegand Herbarium was merged with the Bailey Hortorium Herbarium.

**An endowment has been set up for the Herbarium in honor of Professor Clausen by a former student. The funds from the endowment will help to support the maintenance of the Herbarium and its programs.

For further information, please see these references:

Bates, David M. 1984. Robert Theodore Clausen, December 26, 1911-December 31, 1981. Gentes Herbarum 12 (3), pp. 1-7.