Perennial herbs. Hairs eglandular and/or glandular, or 0. Lvs opposite, exstipulate, linear to ovate; cauline lvs connate in pairs or sessile and amplexicaul. Infl. a lax to capitate dichasium; bracts leaflike; epicalyx 0. Calyx bell-shaped or cylindric, 10-veined, 5-toothed; commissures veined, not scarious. Petals 5, white to red or purple, clawed, entire or emarginate or laciniate; coronal scales triangular, paired at base of limb. Stamens 10. Styles 5. Fr. an ovoid or cylindric capsule, dehiscing by 5 entire teeth; carpophore short or long. Seeds reniform, laterally flattened, warty, not winged.