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Joseph Williams Jr.


Research Interest

Plant evolutionary biology


2000 - Ph.D., University of Georgia


My primary research interests are in flowering plant reproductive evolution. Reproduction in flowering plants is a developmental process that involves physical interactions among up to six genetically distinct organisms (male and female gametophytes and sporophytes, embryos and endosperms). These often cryptic interactions can influence the mating system and/or the strength of reproductive barriers, and hence, the degree of inbreeding or outbreeding present in natural populations. My research seeks to understand the evolution of traits that mediate these interactions. At present I am particularly interested in reconstructing historical sequences of developmental changes to the reproductive process in ancient flowering plants. Have an interest in plant reproductive evolution? Please contact me – I’m always looking for motivated students!

Graduate Students

  • Harmony Yomai (2015-present)
  • John Reese (2013- present)
  • Nicholas Buckley (MS, 2012)
  • Mackenzie Taylor (PhD, 2011)

Post-doctoral associates

  • Simon Wallace (2013- 2014)


Visit Google Scholar for more publications.

  • Williams JH, Mazer SJ. 2016. Pollen—Tiny and ephemeral but not forgotten: New ideas on their ecology and evolution. American Journal of Botany, 103: 365-374.
  • Williams JH, Edwards JA, Ramsey AJ. 2016. Economy, efficiency, and the evolution of pollen tube growth rates. American Journal of Botany, 103: 471-483.
  • Williams, JH, Taylor, ML and BC O’Meara. 2014. Repeated evolution of tricellular (and bicellular) pollen. American Journal of Botany 101: 559-571.
  • Williams, JH. 2012. Pollen tube growth rates and the diversification of flowering plant reproductive cycles. International Journal of Plant Sciences 173:649-661.
  • Williams, JH. 2012. The evolution of pollen germination timing in flowering plants: Austrobaileya scandens (Austrobaileyaceae). AoB Plants. DOI: 10.1093/aobpla/pls010.
  • Abercrombie, JM, O’Meara, BC Moffatt, AR and JH Williams. 2011. Developmental evolution of flowering plant pollen tube cell walls: callose synthase (CalS) gene expression patterns. EvoDevo 2:14.

Contact Information

  • 341 Hesler
  • Mailing Address: 569 Dabney Hall, 1416 Circle Dr, Knoxville, TN 37996
  • Phone: (865) 974-6202
  • Fax: (865) 974-3067
  • E-mail:
  • Lab Website