Typical cruciata is an annual of damp acid soils, mostly on the southeastern Coastal Plain, but locally extending north to Tenn. and Ky. on the Cumberland Plateau and a few sites on the adjacent Interior Low Plateaus. Pr (see 1893 addendum) provided a disjunct coll. (MO) from Chalybeate Springs in EDMO, but virtually no trace of associated vegetation now remains. Var. aquilonia Fern. & Schub. is more northern, with broader leaves and more compact racemes. It may intergrade with typical cruciata in Appalachian regions, and research is needed to clarity the distinction (F, Ch, W).