Glabrous perennial or possibly annual; stems thin, weak, to c. 35 cm long, usually simple, sometimes rooting at nodes. Lvs sessile, 2-6 × 0.1-1.2 cm, usually linear, sometimes linear-lanceolate, remotely serrulate; apex acute or subacute. Racemes axillary, alternate (1 to each opposite pair of lvs), very slender and flexuose; peduncles to c. 12 cm long; pedicels very slender, 5-13 mm long, much > linear bracts. Calyx c. 2 mm long; lobes ovate, ± acute. Corolla c. 6 mm diam.; lobes whitish with bluish veins. Capsule 2-lobed, 3-4.5 mm wide, glabrous, > calyx. Seeds oblong-obovate, very flattened.