Stem softly woody with broad pith. Leaves opposite, decussate, serrate, rarely entire, sometimes deeply lobed, deciduous, petiolate. Flowers in terminal paniculate cymes or corymbs, inner central ones regular, bisexual, a few or majority of the outer ones sometimes sterile, long pedicelled. In sterile flowers sepals 4-5, petaloid, enlarged and distinctly veined; petals 4-5, rudimentary or missing. Fertile flowers perfect, regular; sepals 5-4, imbricate; petals 5-4, valvate; stamens 8-10, anthers short; ovary inferior, 2-5-locular, ovules numerous on T-shaped, introflexed parietal placentas; styles 2-5, short, free or united at the base, stigmas terminal. Fruit a 2-5-locular, membranous capsule opening at the top between the styles. Seeds many, minute; testa membranous, reticulate.