This is a widespread eastern tetraploid (2n = 28) that appears to have originated from hybridization of palustris and blanda (Joly & Bruneau 2007). The typical variety (including var. glandulosa (Crepin) Farw.) is predominant in Ky. Open dots indicate good published records of the species, but without det. of variety. The related diploid species, R. foliolosa Nutt. ex. Torr. & Gray, which occurs mostly in Kans., Ark, Okl. and Tex., has been rarely misidentified in Ky. It has more numerous, elongated leaflets, fewer and shorter prickles, shorter stipules. and generally white corollas. R. foliolosa has been reported from c. Miss. and might be expected in w. Tenn or even w. Ky. (FNA 9, W). There appears to be some intergradation between carolina and foliolosa in Mo. (Thomas 2017).