Annual or perennial herbs, rarely shrubs or
twiners. Leaves alternate or opposite, entire or pinnately or palmately
divided, exstipulate. Inflorescence usually terminal, rarely axillary, cymose,
corymbose to capitate. Flowers bisexual, actinomorphic or sub-bilabiate. Sepals
5, more or less connate. Petals 5, gamopetalous, tubular, funnel-shaped or
salver-shaped. Stamens 5, inserted in the corolla tube, anthers 2-celled.
Carpels 3, syncarpous, ovary superior, 3-locular with 1 or more ovules in each
locule, styles simple, stigmas 3-fid. Fruit a capsule.