Mark A. Schlessman

Professor of Biology

I am an evolutionary biologist who loves plants. I am especially interested in the ways that angiosperms distribute stamens and pistils among their flowers in order to specialize more on either the male or the female component of reproductive success.  I’m also working on a flora of the Vassar College Ecological Preserve and on digitizing the Vassar College Herbarium.  I am semi-retired, teaching half time.  I offer a Plant Biodiversity intensive (BIOL 393) each semester through spring 2022, and will teach Ecology and Evolution of Sexual Reproduction (BIOL 355) fall semester 2021.  I co-chair the College Arboretum Committee and oversee our class tree program.

BA, Colorado College; MS, PhD, University of Washington
At Vassar since 1980


Olmsted Hall of Biological Sc
Box 187

Research and Academic Interests

Biology; Plant Diversity & Evolution; Field Botany; Evolutionary Genetics; Ecology & Evolution of Sexual Reproduction

Departments and Programs


BIOL 355 Ecology and Evolution of Sexual Reproduction
BIOL 393 Special Topics in Biology

Selected Publications

Selected Publications (* = student coauthor)

  • Schlessman, M.A., *K. Lee, *C. Perkins, & *M. Harrington. 2020. Effects of fruit set, mineral nutrition, and herbivory on male flower production in andromonoecious Polanisia dodecandra subsp. trachesperma (Cleomaceae). Journal of the Torrey Botanical Society 147(4):338-350.
  • Schlessman, M.A., *L.B. Vary, J. Munzinger, & P.P. Lowry. 2014. Incidence, correlates, and origins of dioecy in the island flora of New Caledonia. International Journal of Plant Sciences 175:271-286.
  • Schlessman, M.A. 2010. Major events in the evolution of sexual systems in Apiales: ancestral andromonoecy abandoned. Plant Diversity and Evolution 128:233-245.
  • Schlessman, M.A., *N. Underwood, *T. Watkins, *L. M. Graceffa, & *D. Cordray. 2004. Functions of staminate flowers in andromonoecious Pseudocymopterus montanus (Apiaceae, Apioideae). Plant Species Biology 19:1-12. 
  • Schlessman, M.A., *N. Underwood, & *L. Graceffa. 1996. Floral phenology of sex-changing dwarf ginseng. American Midland Naturalist 135:144-152.
  • Schlessman, M.A. 1982. Expression of andromonoecy and pollination of tuberous lomatiums (Umbelliferae). Systematic Botany 7:134-139.

In the Media


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Mark A. Schlessman
Photo: Courtesy Mark Schlessman. Dr S in Iceland with Angelica.
Mark A. Schlessman
Photo: Karl Rabe / Vassar College