Annual, 30-100 cm tall, erect, usually bristly hairy below, glabrous and glaucous above, branched. Lower leaves deeply pinnatifid or pinnatisect, 6-25 cm long, 3-12 cm broad, 1-3-jugate with a large ovate terminal lobe and much smaller ovate-oblong lateral lobes, sinuate dentate, stalked; upper leaves becoming much smaller, narrowly elliptic or lanceolate, short stalked. Racemes 40-60-flowered, increasing up to 30 cm in fruit. Flowers 5-8 mm across, bright yellow; pedicel 2-3 mm long, about as long as the sepals in fruit otherwise shorter, ± appressed to the axis, not thickened. Sepals 3-5 mm long, 1-1.2 mm broad, oblong, obtuse, yellowish, glabrous. Petals 7-9 mm long, 3-4 mm broad, obovate, clawed. Stamens c. 4: 5 mm. long; anthers c. 1 mm long. Siliquae 10-20 mm long, 1.5-2 mm broad, including 1.5-3 mm long beak (with c. 1 mm long style and capitate stigma), oblong, subquadrangular; valve with a strong mid-vein, glabrous, subtorulose; septum not veined, membranous; seeds 3-6 in each locule, c. 1 mm in diam., dark-brown (blackish), not mucilaginous when wet; coarsely finely reticulated.