Annual herb up to 30 cm high, not or sparingly branched. Stems glabrous. Lvs mostly in whorls of 2-5 (upper lvs scattered, alternate), glabrous, narrowly elliptic to linear, acute to acuminate, entire, sessile, 5-25 mm long. Fls numerous in dense, simple, terminal racemes; perianth coloured purple toward apex; pedicels 0.5-1 mm long; bracts triangular, c. 0.5 mm long, deciduous; 3 outer sepals ovate-triangular, c. 1 mm long; wings petaloid, elliptic to ovate, 1.5-2 mm long, > corolla; outer petals entire, ± = keel; keel fimbriate toward apex. Capsule glabrous but often scaly, c. 1.5 mm long and not winged, c. 3/4 length of persistent calyx wings; seed hairy, dark brown, narrow-obovate-ellipsoid, c. 1 mm long; strophiole 2-lobed.