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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 ​(MS, 2019)​
  • Nicholas Buckley (MS, 2012)
  • Mackenzie Taylor (PhD, 2011)

Post-doctoral associates

  • Simon Wallace (2013- 2014)


Visit Google Scholar for more publications.

  • Williams, JH, and PE Oliveira. 2020. For things to stay the same, things must change - Polyploidy and pollen tube growth rates. Annals of Botany
  • Williams, JH and JB Reese. 2019. Evolution of development of pollen performance. Current Topics in Developmental Biology 131: 299-336.
  • Reese, JB and JH Williams. 2019. How does genome size affect the evolution of pollen tube growth rate, a haploid performance trait? American Journal of Botany 106(7):1011-1020.
  • Williams, JH, and C Brown. 2018. Pollen has higher water content when dispersed in a tricellular state than in a bicellular state. Acta Botanica Brasilica 32(3): 454-461.
  • Wallace, S and JH Williams. 2017. Evolutionary origins of pectin methylesterase genes associated with novel aspects of angiosperm pollen tube walls. Biochemical and Biophysical Research Communications 487: 509-516.
  • Williams, JH, JA Edwards and AJ Ramsey. 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(4): 559-571.


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