This recently described monotypic genus has a curiously fragmented northeastern range: mostly on bottomlands in and around the central Appalachian region, and locally common along the Ohio Rv. downstream to the greater Cincinnati area. It is threatened, endangered or locally extinct in all states except Ohio and W.Va., where it is still considered "vulnerable" (NS). R. hermaphrodita is a remarkable species has some similarities to the South American genus, Sidasodes, but clearly deserves its own genus (W; Weakley et al. 2017). It is one of the tallest perennial herbs in Ky., potentially reaching 4-5 m on rich damp soil at edges of riparian woods; see also Nabalus crepidineus and Helianthus Sect. Gigantei. Ripariosida can be somewhat weedy in gardens but it is much sought after by larger herbivores, from woodchucks to cattle.