Costus Family

Roger Spencer

Rhizomatous herbs without aromatic oils. Leaves spirally arranged, ligulate and with tubular sheaths. Flower clusters terminal on leafy shoots or borne directly on the rhizome, sometimes surrounded by sterile bracts. Flowers solitary or in pairs in the bract axils. Calyx tubular, often split on one side. Flower tube usually longer than the calyx, divided into 3 slightly unequal lobes. Lip conspicuous or not, the lateral sterile stamens absent or tooth-like. Fertile stamen 1, filament petal-like. Fruit a dehiscent capsule sometimes breaking up irregularly.

A tropical family formerly included in the Zingiberaceae, the plants grown ornamentally in the tropics and occasionally in cooler climates as indoor pot plants. Often included in the Zingiberaceae. Tapeinochilos is sometimes grown as T. ananassae.

A few species have medicinal properties; C. speciosus is the source of diosgenin.

Similar to Zingiberaceae but aerial parts not aromatic; leaves spiral (not distichous) and with closed sheaths; floral lip formed from 5 united sterile stamens of both whorls (not 2 united sterile stamens from the inner whorl as in the Zingiberaceae).

4 genera and about 100 species throughout the tropics.

Source: Spencer, R. (2005). Costaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 5. Flowering plants. Monocotyledons. The identification of garden and cultivated plants. University of New South Wales Press.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Lilianae
order      Zingiberales
Higher taxa
Subordinate taxa
genus        Cheilocostus
genus        Costus L.