Plants
with alternate or basal leaves, stipulate; flowers perfect, axillary, nodding;
sepals 5, corolla somewhat irregular, 1-spurred, 5 petals; stamens 5, anthers
adnate, united over the pistil, lower pair spurred in some species; fruit a
3-valved capsule. Cleistogamous
flowers are sometimes found in addition to normal flowers, or showy flowers may
be sterile.