The population genetics of this highly localized endemic is compared with that of its widespread prairie relative E. angustifolia var.
Most variability occurs within rather than among populations, for both species.
Morphological similarities between E. tennesseensis and E. angustifolia have resulted in a lack of consensus regarding their taxonomic distinctiveness, but the two are genetically distinct. In addition, E. tennesseensis diverges from morphologically distinctive E. purpurea at a similar mean genetic identity value of 0.813. Thus, the rare E. tennesseensis has less genetic variability than the widespread E. angustifolia , and the two differ genetically at a level similar to that found between E. tennesseensis and a more morphologically distinctive Echinacea species.