Annual or biennial. Taproot stout or tuberous. Stems erect, to 1 m high, herbaceous, branched, usually with stiff bristles. Basal leaves petiolate, pinnately lobed, bright green, with stiff bristles; upper leaves sessile, oblong-lanceolate, becoming glabrous, base dilated and deeply cordate, clasping stem. Inflorescence with open flowers overtopping or equalling buds. Sepals erect to inclined, 4–6 mm long; petals 6–11 mm long, bright yellow; outer stamens with filaments curved outwards at base; ovary sessile. Fruit obliquely erect, 4–7 cm long (including beak), c. 3 mm wide, somewhat constricted between seeds; valves somewhat flattened, midrib prominent, lateral veins obscure, parallel; beak 7–22 mm long, seedless or rarely with 1 seed; pedicel 5–30 mm long; seeds 1–2 mm wide, red to black-brown. Flowers mainly spring and autumn.