Annual or perennial herbs, shrublets or shrubs. Stipules lateral. Leaves alternate, simple (in ours), petiolate. Sepals 5, usually linear and with a short horn just behind the apex, stellately hairy. Petals 5, yellow or orange. Stamens 4-40. Ovary 2-5-locular. Fruit a capsule, usually spherical (rarely ovoid), echinate or setose.

Note: mature fruits are essential in naming these species. The measurements of fruit diameters include the aculei.