References
For Polymnia
Cronquist, A. 1980. Asteraceae, Volume I, Vascular flora of the Southeastern United States. University of North Carolina Press, Chapel Hill, N.C. Google Scholar
Estes, D., and J. Beck. 2011. A new species of Polymnia (Asteraceae: tribe Polymnieae) from Tennessee. Syst. Botany 36: 481-486. Google Scholar
Pittman, A.B., V. Bates, and R. Kral. 1989. A new species of Polymnia (Compositae: Heliantheae) from the Ouachita Mountain region of Arkansas. Sida 13: 481-486. Google Scholar
Strother, J.L. 2006ll. Polymnia. In Flora of North America Editorial Committee. 2006b. Flora of North America north of Mexico. Volume 20, Magnoliophyta: Asteridae, part 6: Asteraceae, part 2. Oxford Univ. Press, New York, NY. 666 pp. Google Scholar
Wells, J.R. 1965. A taxonomic study of Polymnia (Compositae). Brittonia 17: 144-159. Google Scholar