This is widespread on seasonallly wet acid soils in eastern and central North America, but rare to absent from the Gulf Coastal Plain to Tex. Compared to alatus (the only congener in eastern North America), ringens differs as follows (FNA 17, W): stems with rounded angles (versus winged); leaves sessile (versus petiolate except distally); pedicels mostly 20-45 mm long (versus 2-15 mm).