Annuals 3-30 cm tall. Stems ascending to erect, angular, branched from base, glabrous. Basal leaves short petiolate; leaf blade spatulate, 1.5-2 cm × 6-8 mm, base narrowed, apex rounded, midvein distinct. Stem leaves sessile, lanceolate, elliptic, or ovate-elliptic, 0.4-2 cm × 3-7 mm, base obtuse, apex acute to obtuse, midvein distinct. Cymes lax, terminal and axillary. Flowers 5merous, variable in size. Pedicel spreading to erect, to 6 cm, angular, glabrous. Calyx tube 1-1.5 mm; lobes elliptic to ovate or rarely lanceolate, 4-8(-11) × 1.5-2.5 mm, base obtuse, apex obtuse to rarely acute, veins 1-3. Corolla blue, usually 0.8-2 cm in diam., tube 1-1.5 mm; lobes elliptic to ovate-elliptic, 0.8-1.4 cm, apex acute. Nectary connate at base into a tube pointed outward, apex lamellate, margin lobed. Filaments 5-7 mm; anthers blue, ellipsoid, 2-2.5 mm. Ovary ovoid-ellipsoid, apex triangular acute. Stigma lobes triangular, decurrent to apical part of ovary. Capsules cylindric, as long as persistent corolla. Seeds brown, subglobose, ca. 1 mm in diam. Fl. and fr. Aug-Oct. 2n = 40.