Costus afer, known as spiral-ginger, is a terrestrial herb native to Tropical Africa. It belongs to the family Costaceae and is found in countries including Angola, Benin, Cameroon, and others. It grows in open areas, forest margins, and near water sources, often on sandy or rocky soils, at elevations up to 1770 m. The plant can reach 0.5–4 m in height and has narrow elliptic to obovate leaves. Its inflorescence is many-flowered, globose to ellipsoid, and terminates leafy or occasionally leafless shoots. The flowers are white with a yellow nectar guide and reddish margins, and the bracts are green with a reddish upper margin. It is often confused with C. dubius but is distinguished by its leafy shoot-terminating inflorescences and 1- or 2-flowered bracts.
Description
Costus afer is a perennial herb in the family Costaceae, native to tropical regions of Africa. It is commonly found in open places such as roadsides, forest margins, and near rivers, often in wet habitats. The plant is erect, with individual shoots sometimes bending down in fruit. Leaves are numerous, with sheaths, ligules, and petioles that can be glabrous or hairy. The ligule is 4–11 mm long, and the lamina is narrowly elliptic to obovate. The inflorescence is many-flowered, globose to ellipsoid, and terminates a leafy or, rarely, a leafless shoot. Flowers are white with a yellow nectar guide and reddish margins. The bracts are green with a reddish upper margin and are 1- or 2-flowered. Costus afer is often confused with C. dubius but is distinguished by its leafy shoot-terminating inflorescences and the presence of pink margins on the labellum.
