Annual herb to c. 20 cm tall, sometimes single-stemmed with the slender vegetative shoots tending to trail, but not rooting at nodes; sap slightly milky. Lower lvs and those of vegetative stems with short ciliate petioles. Lamina 1-3 × 0.5-1 cm, elliptic, elliptic-obovate, or spathulate, occasionally lanceolate, generally ciliate, especially towards the narrow attenuate base and on the midrib beneath, crenate or dentate. Lvs below infl. linear or lanceolate, entire, usually glabrous. Infl. a loose raceme of few fls on slender glabrous peduncles 1.5-4 cm long. Calyx 7-12 mm long; lobes linear or subulate, = to > 2× tube, glabrous, often purplish. Corolla 1.1-1.7 cm long to apex of lobes of lower lip, usually dark or violet blue, occasionally pinkish mauve; lower lip usually with white or yellowish throat bands on either side, occasionally corolla concolorous, 3-lobed; lobes (5)-7-10 × c. (3)-5 mm, ± broad-elliptic-oblong or obovate, slanting downwards, often mucronulate. Stamens blue; lower 2 anthers bearded at apex. Capsule c. 5 mm long, narrow-obconic. Seeds c. 0.5 mm long, ellipsoid, brown, glossy.