Of course, it's a bit of a miracle that we still have this delightful perennial with us. Tennessee coneflower is only found in a few counties in Tennessee, and if heroic stewards hadn't stepped in to save it, our world would be less colorful. It was discovered in 1878 by Augustin Gattinger, and less than a century later in 1961 its absence in field surveys led some researchers to claim it extinct. Later in the 60's it was rediscovered; however, survival wasn't guaranteed as the land some populations inhabited was cleared to make way for trailer parks and housing developments. We have people like the late Dr. Elise Quarterman to thank for advocating for this species's livelihood. Efforts from her and others helped the plant become listed on the endangered species list, one of the first flora ever. This attention led to areas where Echinacea tennesseensis occurred being protected, and with enough populations safe, the species was delisted in 2011, certainly a success story for horticulture and humankind's intervention.
The endemism is a peculiar subject. Why is such a floriferous species isolated to just a few counties in Tennessee? Sure, humans destroyed a few sites, but it seems that it never had the wide distribution that some of the other Echinacea genera enjoy. The current hypothesis is that the species arose during the hypsithermal interval, a period of climatic warming and drying that occurred around 5000—8000 years ago. Drier conditions opened the woodlands of middle Tennessee and allowed the colonization of prairie species like our Echinacea. When the climate cooled and became more moist, forests began to reclaim the land, and this stress-tolerant species began to decline in numbers. Walck et al. (2002) state that its narrow endemism is due to several factors—seed-based reproduction; large seeds that aren't animal or wind dispersed; self sterility; intolerance of shading; a lack of seed persistence in the soil, and few individuals making it to adulthood in the wild. All these characteristics would have limited its dispersal from middle Tennessee.
The xeric-adapted nature of established plants is quite apparent in the root systems. Earlier this spring I had to move some Echinacea tennesseensis, and I was very surprised to discover massive, deep taproots on plants that were only one year old. Unearthing knowledge about roots (in a literal and figurative sense!) is always exciting, like discovering buried treasure. I expected to see more rhizomatous roots like those on Echinacea purpurea (purple coneflower) that I've transplanted much of my life . The soil had mostly sloughed off one taproot, so I rinsed it to get a better look. Near the crown it was as thick as a plump carrot! From there, the chthonic organ divided with depth, but the roots were still stout. (Yes, most of the transplants survived in case you are wondering.)