This southeastern annual or short-lived perennial (?) is most frequent in the central and lower Mississippi watershed (F, Cr, W). It is known from s. Ind., and may be overlooked on lowlands in the Shawnee Hills of Ky. D. brachiata usually grows in less disturbed woods on damp fertile soils of riverine floodplains. It is the probably the most shade tolerant species of Acanthaceae in eastern states; 2n = ca. 80.