Annual or perennial herbs, often from a rootstock, erect or loosely spreading. Leaves opposite,
often in unequal pairs, sometimes fleshy, entire or shallowly sinuate. Inflorescences terminal and axillary, paniculate, umbellate or cymose. Flowers small, quickly falling off, bisexual. Perianth: lower
part constricted above ovary, upper part petal-like, campanulate,
slightly 5-lobed, caducous. Stamens 1-4(-6); stamens or styles exserted or included. Fruit fusiform,
clavate or turbinate, conspicuously 3-5(-6)-ribbed, glabrous or
glandular pubescent, but without glands.
Derivation of name: Named in honour of Herman Boerhaave (1668 - 1738), a Dutch botanist, Christian humanist and physician.
Worldwide: 20 species in the tropics and subtropics, some widespread weeds.
Zimbabwe: 4 taxa.Insects associated with this genus: