Costus afer Ker Gawler, Costaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: spiral ginger

Habit:  herb

Description:  "Terrestrial.  Leafy stems erect, reaching a length of 10-12 feet.  Leaves very variable in size, oblong or oblong-lanceolate, 3-9 inches long, 1-3 inches broad at the middle, acuminate, moderately firm, rounded at the base to a short bread petiole, glabrous or softly pubescent beneath; ligule very short.  Spikes globose, 1-3 inches long, 1 1/2-2 inches in diameter, usually sessile at the end of the leafy stems; bracts suborbicular, glabrous, the outer 3/4-1 inch long and broad.  Calyx shorter than the bract; lobes ovate, obtuse.  Corolla-lobes oblong, acute, about 1 inch long.  Lip 1 1/2 inches long and broad, white or red, with a yellow centre; process that bears the anther 1/4-1/3 inch broad, nearly as along as the lip, incurved at the tip"  (Thiselton-Dyer, 1898; p. VII:299).

Similar to Costus dubius but "usually has a pink-edged labellum (but sometimes pure white), and has 2 flowers per bract"  (Daehler & Baker, 2006; p. 6).

Habitat/ecology:  (no habitat/ecology info known by PIER)

Propagation:  Seed

Native range:  Tropical Africa (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced cultivated	Imada, Clyde T./Staples, George W./Herbst, Derral R. (2013) Reported cultivated in the National Tropical Botanical Garden but not confirmed.
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced cultivated	Imada, Clyde T./Staples, George W./Herbst, Derral R. (2013) Cultivated in Waimea Arboretum & Botanical Garden

Control:  If you know of control methods for Costus afer, please let us know.