I probably haven't seen enough to comment on the full range of variation of either, but they do seem like distinct entities at either end of the spectrum. I would be inclined to let both spp. stand for now (and sinking the Liatris pauciflora var. secunda name) but really I'd defer to whatever @jayhorn thought best, I get the sense that he has a better idea of any of us where one species stops and the other begins.

I think this certainly warrants species treatment, but would also like to see @jayhorn's thoughts

The Sabtatia bartramii/S. decandra issue vexed me sufficiently that I requested that it be taken care of about a month ago. It might be a good move to attempt to systematically reconcile such issues. More remain, and I'll compile a list. Does anyone with curatorial powers want to help me out?