Annual or biennial, erect, much branched, glabrous herb, hardly reaching up to 30 cm in height; branches tetragonous, winged; leaves small, linear-lanceolate, usually with recurved margins; stipules very small, acute or bristly; flowers white, pink or purple, on axillary 2-4 flowered peduncles; calyx-tube 4-toothed, persistent, distant in fruits; corolla salver shaped, tube slender; lobes ovate; shorter than corolla tube; stamens 4, epipetalous, inserted in the throat of corolla, ovary 2-locular; each locule with numerous ovules in axile placentation; style filiform; capsule longer, ovoid or subglobose, glabrous, indehiscent, valves protruding beyond the sepals; seeds ellipsoid, angled or globose.