A cosmopolitan family, mainly of herbs, represented in West Africa by erect perennial herbs and undershrubs rarely over 2 m high, and a very few shrubs, in savanna and upland grassland. Apart from a few weed or culinary species introduced from the New World, our flora has only Old World affinities. Almost all West African genera have at least one species which also occurs in other parts of tropical Africa, sometimes in southern Africa and the Old World tropics in general as well; but within West Africa, most species have only local distributions. Gambia is recorded as having only five species (four genera), only Leucas martinicensis being indigenous.

Members of the family may be recognised by their four-sided stems bearing simple, exstipulate opposite or whorled leaves, which are often glandular and generally aromatic when crushed, small, toothed and either petiolate or sessile. Only lcomum (one to two species of tiny herbs in Guinée) has alternative leaves. The flowers are small, two-lipped, with four stamens, which usually lie on, or rise from, the bottom lip in West African species. White, pink, blue, violet and purple are common flower colours; yellow, orange and red are quite rare. Inflorescences are short axillary cymes, assembled in various ways into, for example, terminal and axillary interrupted spikelike structures (Ocimum), dense cone-like ‘spikes’ (Haumaniastrum, Hyptis), globular nodal clusters (Leonotis) or lax, spreading panicles (Englerastrum, Hoslundia). There is some doubt as to whether Haumaniastrum can be maintained as a genus separate from Acrocephalus (Robyns, 1966).