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Peter Bernhardt, Ph.D.

Professor (Retired)

Courses Taught

Plants and Fungi, Ethnobotany, Pollination Biology, Biology and Classification of Orchids


Ph.D., University of Melbourne, 1981 

Research Interests

The use of flowers as model systems to study the evolution of reproduction began with the experimental and interpretative work of Charles Darwin in the 19th century. This discipline has grown even more important in the 21st century as it is applied to the investigation of breeding and pollination systems in rare and threatened species. It's a two step process. In the field, Bernhardt and his lab record biochemical and morphological changes over the life span of flowers, identifying and sampling the animals that visit the blossoms and conducting field experiments to determine whether cross-pollination is required to set seed. The plant and animals specimens they bring back to the lab must be analyzed to help answer our questions. They remove and identify the pollen grains carried by prospective pollinators. Bernhardt and his colleagues employ a series of fix, wash, squash preparations for recording the progress of pollen tubes inside pistils using fluorescence microscopy. All projects are investigated in association with research colleague, Retha Meier.

Labs and Facilities

The Bernhardt/Meier lab works with colleagues at the following institutions; the Missouri Botanical Gardens (St. Louis, USA), the Missouri Department of Conservation (St. Louis), the Anderson Prairie Reserve (Welda, Kansas). Ongoing projects within the Bernhardt/Meier lab include...

  • Pollination and breeding systems of endangered lady's slipper orchids (Cypripedium species).
  • Pollination and breeding systems in milkweeds (Asclepias species) native to the American midwest.
  • Floral ecology and breeding systems of the vernal, woodland flora of the American midwest.
  • Comparative reproductive success in two color morphs of the birds foot violet (Viola pedata)
  • The roles of interspecific isolation mechanisms and pollination networks in forests and wet meadows of the Chinese Himalayas

Publications and Media Placements

Gods and Goddesses in the Garden. 2008. Rutgers University Press.
The Rose's Kiss. 1999. University of Chicago Press.
Darwin's Orchids: Then and Now -

Popular articles on orchids, pollination and conservation*

Surviving a Decade of Drought?--Some Cypripedium species of Lijiang, Yunnan
A Natural History of Orchids in Yunnan --Bad Times for Cypripediums in Shangri-la
A Natural History of Pollination at a Shrine

Book reviews and interviews for "The Science Show," ABC radio (Sydney, Australia)... 

"Germaine Greer rehabilitates her patch of SE Qld"
"The secret language of bees"
"Orchid research in China and Australia"
"Museums hold species not yet named and maybe now extinct"

SLU Botanist Shares Knowledge around the World and on Campus
SLU Scientists Recognized for Pollination Ecology Research

Recent peer-reviewed publications (since 2015):

Bernhardt, P. Camilo, G.R. & Weston P.H. 2019. Shaken vs. scraped: floral presentation contributes to pollinator guild segregation in co-blooming Symphionema montanum and Isopogon anemonifolius (Proteaceae). The Gardens’ Bulletin Singapore 71: 377-398.

Ren, Z.-X., Bernhardt, P., Edens-Meier, R., Zweck, J., Arduser, M., Li, H.-D. & Wang, H. 2018. Comparative pollen-pistil interactions and insect pollination in two Hypoxis species (Hypoxidaceae) in China and North America. Plant Systematics and Evolution,

Liang, H, Ren ZX, Tao, ZB, Zhao, YH, Bernhardt, P., I, DZ, Wahgn, H. 2018. Impact of pre- and post-pollination barriers on pollen transfer and reproductive isolation among three sympatric Pedicularis (Orobobanchaceae) species. Plant Biology, doi: 10.1111/plb. 12833

Tao, Z-B., Rwn, Z-X. Bernhardt, P., Wang, W. J.. Liang, H., Li, H-I & Wang, H. 2018. Nocturnal hawkmoth and noctuid moth pollination of Habenaria limprichtii (Orchidaceae) in sub-alpine meadows of the Yulong Snow Mountain (Yunnan, China). Botanical Journal of the Linnaean Society, boy023,

Zhie-Bin T, Ren Z-X, Bernhardt P, Liang, H, Li H-D, Zhao Y-H, Wang, H, Li, D-Z. 2018. Does reproductive isolation reflect the segregation of color forms in Spiranthes sinensis (Pers.) Ames complex (Orchidaceae) in the Chinese Himalayas. Ecology and Evolution. DOI: 10.1002/ece3.4067

Edens-Meier, R., Ardues, M., Camilo, G.R. & Bernhardt, P. 2018. Comparative pollination ecology between to populations of Cypripedium parviflorum (Orchidaceae) in Missouri, United States of America - does size matter?  Botanical Journal of the Linnaean Society. link

Bernhardt, P., Edens-Meier-R., Grimm, W., Ren, Z.X., Towle, B. 2017. Global Collaborative Research on the pollination biology of rare and threatened orchid species (Orchidaceae). Annals of the Missouri Botanical Garden 102: 364-376.

Domic, A. I., Bernhardt, P., Edens-Meier, R., Camilo, G.R. & Capriles, J.M. 2017. Pollination ecology of Polylepis tomentella (Rosaceae), an Andean Anemophilous tree presenting a potential floral fungal infection. International Journal of Plant Sciences 178:

Edens-Meier, R.M., Brown, G., Zweck, J., Arduser, M., Edens, J., Dickson, T.L., Nonnenmacher, H., Westhus, E. & Bernhardt, P. 2017. Reproductive ecology of Asclepias meadii Torr. (Apocynaceae), a federally threatened species. Journal of the Torrey Botanical Society 144:218-229. doi:

Yan-Hui Zhao, Zong-Xin Ren, Amparo Lázaro, Hong Wang, Peter Bernhardt, Hai-Dong Li, De-Zhu Li. 2016. Floral traits influence pollen vectors' choices in higher elevation communities in the Himalaya-Hengduan Mountains. BMC Ecology. 16: 26.

Hai-Dong Li, Yan-Hui Zhao, Zong-Xin Ren, Zhi-Kun Wu, Lorne M Wolfe, Peter Bernhardt, Hong Wang. 2016. Fitness-related selection on floral traits in the distylous plant Primula poissonii (Primulaceae). Journal of Plant Ecology. DOI: 10.1093/jpe/rtw055,

Walters, S.A., Bernhardt, P., Joseph, M. & Miller, A.J. 2016. Pollination and sterility in horseradish. Plant Breeding. DOI: 10.1111/pbr.12413.

Bernhardt, P., Edens-Meier, R., Jocson, D., Ren, Z.X, Zweck, J., Camilo. G. & Arduser, M., 2016. Comparative floral ecology of bicolour and concolour morphs of Viola pedata (Violaceae) following controlled burns. Journal of Pollination Ecology 19: 57-70.

Zhao, Y-H, Ren Z-X, Bernhardt, P., Li, H-D, Tao, Z-B, Li, S-L, Wang, H. 2016. Variation in floral traits and floral abundance versus pollinator diversity along an elevation gradient in species rich meadows of the Himalayan-Hengduan Mountains. BioMed Central Ecology 16:26, doi: 10.1186/s12898-016=0080-1

Brown, G.K., Herrera, J., Bernhardt, P. & Edens-Meier, R. 2015. Potential fungal pathogens of Mead’s milkweed (Asclepias meadii, Apocynaceae). Natural Areas Journal 35: 500 – 506.