A mainly Old World family, represented in West Africa by only four genera and c. 45 species in diverse habitats, but mainly in forest. Aframomum and Kaempferia are tropical African in distribution, while Renealmia and Costus are chiefly American.

All are perennial herbs with fleshy rhizomes occasionally with tuberous roots, producing terminal cymose inflorescences of conspicuous ± sweetly scented flowers. The inflorescences are either carried separately on the rhizome from the unbranched leafy shoots or leafy pseudostem (formed, bananafashion, in Kaempferia and two species of Renealmia) or they appear as branches at the base of the leafy shoot. In some Costus spp., and Hedychium coronarium, the inflorescence is terminal on the leafy shoot, while in C. dinklagei and four West African species of Aframomum (amongst others), the inflorescences are lateral and the shoots bearing them hapaxanthic (Hallé, 1979). The leaves are arranged distichously, those of Aframomum, Alpinia and Renealmia in a plane at right angles to the length of the rhizome, those of Kaempferia, Curcuma, Hedychium and Zingiber in line with the rhizome. Phyllotaxy in Costus is spiral. Each leaf has an entire blade ± false petiole, and an open leaf sheath. There is often a ligule or a pair of ligules but never a pulvinus. The leaf blade is closely pinnately veined, the two margins symmetrical except perhaps at the very base.

The inflorescences can be congested and cone-like, with prominent spiral bracts.