Brassica juncea (L.) Czern.

Annual herb with lax rosette. Stems erect, glabrous, to 1–(2) m tall. Lvs glaucous, glabrous or sparsely hairy, all petiolate. Lower lvs lyrate-pinnatifid to lyrate-pinnate, with large terminal and 1–2 pairs of lateral lobes, 8–15–(20) × 5–8 cm; margins dentate. Upper lvs simple, becoming linear, toothed to entire, 20–50 × 3–10 mm. Racemes to 45 cm long; open fls about level with buds, or lower. Sepals erecto-patent, narrow-oblong, 4–6 × c. 1 mm. Petals yellow, 6–8 × 2–3 mm. Lateral stamens spreading. Silique terete, glabrous, linear, constricted between seeds, 15–25–(40) × 1.5–2.5 mm; gynophore 0; valves with prominent median and weaker lateral veins; beak tapering, seedless, 5–10 mm long. Seeds yellow to brown, 1–2 mm diam.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

Flowering: Sep.–Feb.; Fruiting: Sep.–Feb.