Annual or perennial herbs. Hairs glandular and/or eglandular or 0. Lvs opposite, exstipulate, linear-oblanceolate to linear to subulate, often glaucous; cauline lvs connate in pairs. Fls solitary or in lax to capitate cymes; bracts leaflike; epicalyx scales mucronate to obtuse, papery or membranous or scarious, rarely 0. Calyx narrowly cylindric or narrowed at apex, 5-toothed, with scarious veinless commissures between the teeth. Petals 5, pink or white, clawed or not, entire, 2-fid or toothed; coronal scales 0. Stamens 10. Styles 2. Fr. a cylindric to ovoid capsule, dehiscing by 4 teeth; carpophore usually present. Seeds flattened or folded around the hilum, scutate, warty or finely ridged, not winged.