Perennial or sometimes annual herbs. Hairs eglandular or glandular, or 0. Lvs opposite, exstipulate, usually linear or linear-lanceolate, often glaucous; cauline lvs connate in pairs. Fls solitary or in lax to compact cymes; bracts leaflike; base of calyx tightly enclosed in an epicalyx of 2-6 awned scales. Calyx tubular, usually at least 35-ribbed, 5-toothed, with green commissures. Petals 5, white, pink or red, clawed, usually toothed or fringed, often bearded; coronal scales 0. Stamens 10, in 2 equal or unequal whorls. Styles 2. Fr. a cylindric capsule dehiscing by 4 teeth; carpophore usually present. Seeds flattened, scutate, finely grooved, not winged.