Costus dubius (Afzel.) K.Schum.

Schumann, K.M. (1904) Pflazenreich Heft 20: 409.

African Costus

Tall perennial herb up to 2 m high.

Leaf blades obovate-elliptic, 20-30 x 4-9 cm, cuneate at the base, free petiole 0.5-0.6 cm long, sheathing petiole about 3 cm long forming a prominent shoulder. Venation +/- parallel but each vein attached to the midrib., surfaces pubescent.

Inflorescences borne on separate stalks arising from the rhizome. The inflorescence is rounded, with tightly fitting green bracts, out of which white flowers with a yellow-centered labellum arise. A single flower is borne in each bract.

Fruit enclosed in fleshy bracts. Many seeds per fruit. Young seeds grey turning black on maturity.

Features not available.

An introduced species originally from West Africa but now naturalised in NEQ. Altitudinal range from near sea level to 800 m. Grows in rainforest and notophyll vine forest.

Cultivated as ornamentals or house plants and locally used for medicinal purposes. Inflorescence used for eye treatments; pregnancy, antiaborifacients and the stem for naso-pharyngeal affections (Burkill 1985).