Herbs, annual or perennial, usually erect. Leaves opposite or pseudoverticillate, linear to obovate; stipules fimbriate or scarious. Flowers many, in spreading or condensed cymes. Sepals 5 scarious, sometimes coloured. Petals 5, entire, 2-toothed or
erose marginate . Stamens 5, united together and with the petals forming a tube. Ovary 1-locular, ovules few to many; style slender, 3-fid. Capsules 3-valved; seeds ovoid or flat.
Tropical and subtropical regions; ca 50 species, 3 species in India.
KEY TO THE SPECIES
1a. Leaves radical ones in rosettes, obovate to spathulate; flowers in spikes at top of fasciculate or subumbellate branches