Rapistrum rugosum (L.) All.

Annual herb. Stems weakly ribbed, bearing slightly deflexed short tapered hairs, but ± glabrous above, and below with age, (10)–20–60–(80) cm tall. Lvs serrate to dentate, petiolate, hairy with short tapered hairs. Lower lvs pinnate to pinnatifid or rarely not lobed, (2)–8–20 × (1)–2–7 cm, with a large ovate-oblong terminal lobe and (0)–1–4 pairs of oblong lateral lobes. Upper lvs ovate to linear, 2–5 × 0.5–1.5 cm. Racemes glabrous or hairy, 10–30–(40) cm long. Pedicels erect, 2–4 mm long. Sepals narrow-lanceolate. Petals pale yellow with darker veins, 6–10 mm long; limb elliptic. Silicle erect, hairy or glabrous, weakly to strongly ribbed and rugose; lower segment cylindric or barrel-shaped, 2–3–(5) mm long; upper segment ovoid to turbinate, 2–4 × 2–4–(5) mm, tapering ± abruptly above; style 2–3 mm long. Upper seed c. 2 mm long, lower c. 1 mm long.

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

Flowering: (Aug.)–Oct.–Jan.–(May); Fruiting: (Aug.)–Oct.–Jan.–(May)