Multiple complementary studies clarify which co-occurring congener presents the greatest hybridization threat to a rare Texas endemic wildflower (Hibiscus dasycalyx: Malvaceae)

  • Melody P. Sain Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Julia Norrell-Tober Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Katherine Barthel Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Megan Seawright Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Alyssa Blanton Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Kate L. Hertweck Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • John S. Placyk, Jr. Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Randall Small Department of Ecology & Evolutionary Biology, University of Tennessee-Knoxville
  • Lance R. Williams Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Marsha G. Williams Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
  • Joshua A. Banta Department of Biology and Center for Environment, Biodiversity, and Conservation, University of Texas at Tyler
Keywords: Hibiscus, Ecological Niche Modeling, Conservation, Phylogenetics, Phylogenomics, RADseq, nextRAD, SNPs, Population Genetics, STRUCTURE, GRANULE-BOUND STARCH SYNTHASE


The Neches River Rose Mallow (Hibiscus dasycalyx) is a rare wildflower endemic to Texas that is federally protected in the U.S.A. While previous work suggests that H. dasycalyx may be hybridizing with its widespread congeners, the Halberd-leaved Rose Mallow (H. laevis) and the Woolly Rose Mallow (H. moscheutos), this has not been studied in detail. We evaluated the relative threats to H. dasycalyx posed by hybridization with H. laevis and H. moscheutos by 1) examining their relatedness to one another via modern phylogenomic methods, 2) examining the species’ ecological (dis)similarities to one another using ecological niche modeling, and 3) looking for genomic evidence of hybridization among the three species. Our results suggest that H. dasycalyx is very closely related and ecologically similar to H. laevis, and suggest that H. laevis is interbreeding with H. dasycalyx in the wild. Conversely, H. moscheutos appears to be more distantly related to H. dasycalyx and more ecologically dissimilar, and the two are most likely not hybridizing. For these reasons, we believe that H. laevis poses a greater threat to H. dasycalyx than H. moscheutos. We offer some hypotheses as to why H. dasycalyx and H. laevis are coming into secondary contact where hybridization can occur.


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How to Cite
Sain, M. P., Norrell-Tober, J., Barthel, K., Seawright, M., Blanton, A., Hertweck, K. L., Placyk, Jr., J. S., Small, R., Williams, L. R., Williams, M. G., & Banta, J. A. (2021). Multiple complementary studies clarify which co-occurring congener presents the greatest hybridization threat to a rare Texas endemic wildflower (Hibiscus dasycalyx: Malvaceae). Journal of the Botanical Research Institute of Texas, 15(1), 283-308.