Costus giganteus
Costus giganteus Welw. ex Ridl.
Costus giganteus is a terrestrial herb in the Costaceae family, native to the Gulf of Guinea Islands. It grows in rainforest habitats, often in wet or disturbed areas, at elevations of 0–1450 m. The species is distinguished by its separate flowering shoots, red bracts, and yellow tubular flowers. It is unique in the African Costus genus for having an open floral throat, allowing easier access for pollinators. The plant can reach 1–8 m in height, with large, elliptic leaves and ovoid inflorescences. Flowers are 1–2 per bract, with a fleshy corolla and a tubular, crenulate labellum. The capsule is obovoid, and seeds are small with a large aril.
Description
Costus giganteus is a terrestrial herb from the Gulf of Guinea Islands, growing in rainforest at elevations up to 1450 m. It is characterized by separate leafless flowering shoots, red coriaceous bracts, and yellow tubular flowers with an open throat. The plant reaches 1–8 m tall, with narrowly elliptic to obovate leaves up to 52 cm long and 16 cm wide. The inflorescence is ovoid, 12–20 cm long, with bracts 3.5–6 cm in size. Flowers have a yellow corolla 75–85 mm long, with lobes that form a hood over the stamen. The labellum is yellow, tubular, and crenulate, while the stamen is erect, yellow, and cucullate. The capsule is obovoid to subglobose, and seeds have a large aril. This species is unique in the African Costus genus for its open floral structure and yellow tubular flowers, distinguishing it from other species like C. gracillimus and C. deistelii.
Distribution
Global · Gulf of Guinea Is.
