This species is closely related to C. collina Sims, well-known in cultivation, and similar to it in habit (not to C. alliariifolia, as stated in some reference books).
Among closely related species, two are of special interest: C. annae Kolak., with large flowers to 4-5 cm long and C. schistosa Kolak., stems 20-30 cm, flowers 4-5 cm long. Z 5 (4). Both new.