Dr. Jacobsen received his B.S. from the College of Idaho and his M.S. and Ph.D. in systematic botany from Washington State University. In addition to his administrative and programmatic activities at the Institute, he teaches a course in the Biological Sciences department. He is also a research associate in the Section of Botany at the Carnegie Museum of Natural History and an adjunct scientist at the Pittsburgh Poison Center at Children's Hospital.
Dr. Jacobsen's primary research interests include vascular taxonomy, especially of Allium (onion, Liliaceae) in North America, and toxic plants and fungi. A current collaborative project with the Pittsburgh Poison Center systematically investigates pediatric plant poisoning. The project involves the statistical analysis of the clinical data on plant poisonings recorded by the American Association of Poison Control Centers Toxic Exposure Surveillance System (AAPCC TESS) from 1985–1994.