Brassica nigra

Annual. Taproot slender. Stems erect, to 1 m high, herbaceous, branched, thin, usually with a bluish spot in axil, bristly at base to glabrous above. Leaves petiolate; basal leaves with 1–3 pairs of irregularly-toothed lateral lobes, bristly on both sides; upper leaves lanceolate, entire, glabrous, often glaucous. Inflorescence crowded. Sepals inclined, 4–5 mm long; petals 7–9 mm long, bright yellow; stamens erect; ovary sessile. Fruit erect-appressed, 1–2 cm long (including beak), 1–2 mm wide, quadrangular; valves slightly constricted between seeds, midrib prominent; beak 1–3 mm long, seedless; pedicel 3–8 mm long; seeds c. 2 mm wide, dark red-brown.