Costus is a genus of herbaceous perennial plants in the family Costaceae, erected by Linnaeus in 1753. It is widespread through tropical and subtropical regions of Asia, Africa, and the Americas.
Costus is often characterized and distinguished from relatives such as Zingiber (true ginger) by its spiraling stems. The genus as a whole is thus often called spiral gingers, but this can also refer to C. barbatus specifically. It is important not to confuse Costus scaber, C. spectabilis etc. with the herb known by the common name "costus".
Costus spectabilis is the floral emblem of Nigeria; its flowers are represented (erroneously in red instead of yellow color) on its coat of arms.
Costus productus and Costus guanaiensis are among the species of Costus with edible flowers. Other Costus species' flowers have also been determined to be edible.
Some Costus species have traditional medicinal and veterinary uses. For example, in Trinidad and Tobago, a mix of Costus scaber juice and crushed Renealmia alpinia berries is used to treat dogs bitten by snakes.
Costus naturally hybridizes, and commercial hybrids have also been produced.
Species
As of June 2024, Plants of the World Online recognises 115 species, as follows:
- Formerly placed here
Numerous other species have been called Costus over the years, but are now regarded as members of other genera. Such genera include Alpinia, Amomum, Caulokaempferia, Cheilocostus, Chamaecostus, Dimerocostus, Hellenia, Paracostus, Renealmia, Tapeinochilos, etc.
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