This is widespread on wet fertile soils in eastern states. It is close to ringens and hybrids have been reported elsewhere (Cr), but never from Ky. (2n = 22 versus 24). A coll. from MARS (MUR) has been referred to "var. nervosa" and a coll. from HICK (MUR) to forma albiflorus House, but these taxa have not been recognized in recent treatments.