This is widespread across southeastern states, especially in thin rocky woods and thickets on dry base-rich soils. Within regions where acid sandy soils predominate, it is generally concentrated in strips along roads made with limestone gravel. Also, it is often planted in Ky. and has spread locally onto the deeper soils of residential areas. Cercis is the only simple-leaved legume in eastern North America, and allied with the tropical genus Bauhinia. Cercideae are all woody plants and lack nitrogen-fixation. C, canadensis is widely cultivated, but other taxa in the genus are sometimes planted across eastern states, then sometimes confused (W). These taxa include C. texensis (S. Watson) Sarg., C. occidentalis Torr. ex Gray and C. chinensis Bunge. Leaves of occidentalis (of western states) are usually distinguishable from canadensis and texensis as follows (Isely 1975, Robertson 1976): orbicular or reniform in overall outline (versus cordate to more or less triangular), some or all with broadly rounded, often emarginate apices (versus acuminate, acute or narrowly rounded), not distinctly tapering toward the tips (versus distinctly tapering), distinctly coriaceous and glossy above (versus distinctly, slightly or not so). However, texensis can sometimes appear intermediate.