Herbs, annual, glabrous. Leaves opposite, somewhat clasping or connate, lanceolate to oblong, petiolate to sessile; bracts herbaceous to subscarious. Flowers in spreading, dichasial cymes, 5-merous, bisexual; pedicels usually 10–30 mm long. Epicalyx absent. Calyx tubular, inflated below, with 5 winged veins, not scarious between veins, 5-lobed. Petals 5, pink to purple, exceeding calyx; coronal scales absent. Stamens 10. Ovary 1-celled, with several ovules; styles 2. Capsule subglobose to ovoid, opening by 4 short teeth; carpophore very short or absent. Seeds several, subglobose, finely tuberculate.
Glabrous annual. Leaves exstipulate. Epicalyx absent. Calyx inflated below, whitish with 5 green wings. Petals 5, pink or purple, long-clawed with entire apex; coronal scales absent. Stamens 10. Ovary unilocular, except at the base where it is 2-locular; styles 2. Capsule ovoid to spherical, pericarp consisting of a thick papery exocarp, dehiscing with 4 teeth, and a thin endocarp, dehiscing irregularly. Seeds numerous, reniform or globose.
Herbs annual. Stems erect, dichotomously branched. Leaves ovate-lanceolate or lanceolate, base slightly clasping. Inflorescence a corymbose dichasium. Calyx narrowly ovate, 5-toothed, 5-winged at angles, inflated below after anthesis. Petals 5, long clawed. Stamens 10. Ovary 1-loculed; ovules numerous. Styles 2. Capsule ovoid, dehiscing with 4 teeth. Seeds numerous, globose, tuberculate.
Infl a loose, open, paniculate cyme; cal strongly 5-ribbed, sharply wing-angled; pet pink or rose, without auricles or appendages; stamens 10; styles 2(3); capsule firm, dehiscent by 4(6) ascending teeth; seeds large, globose; much branched annuals. 4, mainly temp. Eurasia.