Slender to stout, annual to short-lived perennial herb up to 80-(100) cm high. Stems glabrous, simple to much-branched at base. Stem lvs always alternate, glabrous, usually linear, narrow-elliptic to obovate at base of stem, acuminate, 1-3-nerved, entire, (5)-8-15-(20) mm long; lvs subtending infl.-branches single, linear, usually < stem lvs. Infl. of few to numerous fls in a diffuse compound dichasium or corymb; sepals elliptic, acuminate, 4-6 mm long, < capsule; inner sepals often fimbriate, at least at flowering; petals usually pale blue or violet and darker veined, sometimes white, 2-2.5× as long as sepals, 7-11 mm long; styles united for (0)-?-(1/2) length. Capsule glabrous, globose, dehiscent, 5-6-(7) mm diam.; seeds elliptic and slightly narrowed to base, shiny light to dark brown, 2.5-3.5 mm long.