It is an annual plant growing to 20–75 cm tall, with a thick, but soft stem. The leaves are spirally-arranged, 2.5–9 cm long and 1–2.5 cm broad, with a deeply toothed margin. The flowers are pink, red, mauve, purple, lilac, or white, and 2.5–5 cm diameter; they are pollinated by bees and other insects, and also by nectar-feeding birds.[3] The ripe seed capsules undergo explosive dehiscence