Description from Flora of China
Annual herbs. Leaves alternate; leaf blade simple. Flowers axillary, solitary or paired; epicalyx lobes 3, acute, caducous. Calyx 5-lobed, divided almost to base. Petals 5, red. Stamens 15, in 5 groups of 3 alternating with staminodes, connate at base into tube; staminodes 5, nearly as long as petals; anther 2-celled, extrorse. Ovary sessile, 5-locular; ovules many per locule; style elongated. Capsule ovoid-globose, dehiscent into 5 mericarps. Seeds 8-12 per mericarp, in 2 rows, elliptic, with endosperm; cotyledons 2-divided, plicate.
One species: widespread in tropical Asia; introduced in China.