An annual or a biennial, 45-75 cm tall. Stem striate, glabrous, fistular when old. Leaves 3-8.5 cm long, 5-12 mm broad, linear to oblong-lanceolate, entire. Flowers yellow, in spicate racemes, 10-26 cm long; bract c. 3 mm long, up to 4 mm in fruit, lanceolate, persistent, margin membranous. Sepals 4, c. 4 mm long, ovate to oblong, persistent. Posterior petal 5-10-fid; appendage c. 1/3 the size of the petal, 2-nerved. Filaments persistent. Capsule 3-5 mm long, erect, subglobose, with 3 prominent stigmatic lobes. Seeds c. 1 mm long, glabrous, brownish-black, glossy.