Annual or perennial herbs, rarely shrubs.
Leaves alternate or opposite, entire or pinnately, or rarely palmately divided.
Flowers regular, bisexual, in cymose, often helicoid inflorescence, sometimes
flowers solitary and axillary. Sepals 5, imbricate, often with appendages in
the sinuses. Petals 5, tubular or funnel-shaped, imbricate or contorted.
Stamens 5, mostly epipetalous, alternate with petals, sometimes inserted
towards the base of tube, anthers 2-celled, linear or sagittate. Carpels 1 or
2, ovary superior, 1-locular, styles 1 or 2, stigmas capitate. Fruits
loculicidal or septicidal capsules, dehiscing by 2 or rarely by 4 valves, or
indehiscent. Seeds minute, often carunculate, variously sculptured.