herbs. Leaves simple, opposite, stipules forming a minute sheath. Flowers
small, white or yellow, rarely pale blue, 4-merous, in terminal or axillary
cymes. Calyx of 4 sepals, connate below forming a campanulate tube, lobes
valvate or reduplicate. Stamens 4, adnate to corolla tube, filaments much
longer than the anthers, anthers ovate, base cordate. Carpels 2, united, ovary
2-locular, ovules many in each locule, styles 2. Fruit a subglobose capsule.
Seeds many, minute, subglobose.