Annual or perennial herbs. Leaves mostly spirally arranged, all radical to sometimes cauline, alternate or opposite, simple, entire to pinnatifid, nerves 1 to many; petioles often sheathing at the base, dilated, sometimes vaginate, membranous, exstipulate. Flowers small, forming short or long axillary spikes or capitate racemes, many to rarely solitary, regular, hermaphrodite, rarely monoecious. Calyx usually herbaceous, 4-lobed, persistant, Corolla hypogynous, gamopetalous, scarious, 3-4-lobed; lobes imbricate spreading at anthesis; tube ovoid to cylindrical. Stamens 4, subequal, inserted on the corolla-tube or alternating with the lobes, rarely hypogynous; filaments filiform; anthers dorsifixed, versatile, 2-thecous; the thecae opening longwise; pollen globose, reticulate. Ovary superior, sessile, often 2-locular or 3-4-locular with imperfect septa; in female flower 1-locular. Style long, filiform, simple, often exserted. Ovules solitary to many in each locule, axile or basal. Fruit a circumscissile, many seeded capsule, or indehiscent and one seeded. Seeds peltate; testa mucilaginous; embryo straight, rarely curved, placed in the middle of the fleshy endosperm.