Annuals 8-20 cm tall. Stems erect, much branched from base, subquadrangular, scabrous along striae. Basal leaves withered at anthesis, short petiolate; leaf blade spatulate, 6-11 × 2.5-5 mm including petiole, base cuneate, apex rounded, midvein distinct. Stem leaves sessile, elliptic-lanceolate to elliptic, to 2 × 0.5 cm, margin usually undulate and revolute, apex obtuse, midvein indistinct. Flowers in terminal and axillary cymes or solitary. Pedicel to 11 cm, spreading to erect, subquadrangular. Calyx 6.5-9 mm; lobes slightly unequal, lanceolate to ovate-lanceolate, margin revolute and dark purple, apex acuminate, midvein distinct. Corolla blue, tubular, 1-1.5 cm × 3-4 mm; lobes erect, narrowly elliptic, 5-7 mm, scales 2, fimbriae ca. 2.5 mm, apex obtuse. Nectaries 10. Stamens inserted at middle of corolla tube; filaments ca. 3.5 mm, base decurrent into wings of corolla tube; anthers yellow, ellipsoid, ca. 1 mm. Style indistinct; stigma lobes suborbicular. Capsules narrowly ellipsoid to ellipsoid, 1.2-1.5 cm. Seeds light brown, ellipsoid, 0.5-0.7 mm; seed coat smooth. Fl. and fr. Aug-Sep.