Erect annual 50–150 cm high, glabrous or almost so.
Leaves lanceolate to elliptic, not cordate at base, lamina 5–8 cm long, 1–4.5 cm wide; margins toothed with lowest pair of teeth ending in spreading or recurved bristles 5–15 mm long; petiole 0.5–5 cm long.
Flowers solitary or in pairs, peduncles 2–3 mm long. Petals 7–8 mm long, yellow.
Capsule linear, 5–8 cm long, woody, opening by 5 or 4 woody valves; seeds numerous, separated by almost complete transverse partitions: stalk 2–5 mm long.