Annual; glabrous herbs. Leaves opposite; bracts herbaceous to slightly scarious. Flowers in spreading dichasia, 5-merous, bisexual; epicalyx absent; calyx tubular, inflated below, with 5 winged veins, not scarious between veins, 5-lobed; petals 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.
1–4 species (opinions vary regarding their rank), native to the Mediterranean and Eurasia; 1 species naturalised in Australia.