Annual rigid herbs. Stems dichotomously branched. Leaves linear. Flowers solitary or in a cymose inflorescence. Epicalyx absent. Calyx narrowly tubular, 5-7-toothed, 5-15-nerved, without scarious spaces between the nerves. Commissural veins absent. Petals 5, with a long claw and a short 2-4-lobed limb. Stamens usually 10. Styles 2. Coronal scales absent. Capsule cylindrical, dehiscing by teeth. Carpophore absent. Seeds acute, with a facial hilum.