This winter annual occurs mostly in the central and lower Mississippi Rv. watershed. It is largely restricted to rocky glades on calcareous soils. The genus Euploca has been separated from Heliotropium as follows (W): stigmatic apex pubescent (versus glabrous); anthers apically coherent (versus rarely coherent); calyx lobed only 1/3-1/2 to base (versus 3/4-1); embryo curved (versus straight).