Dioscorea cirrhosa Lour.

A perennial dioecious herb up to 10 m long, glabrous and scandent, with tuberous rhizome (of 1 or more tubers) of variable shape and size, usually globose or pear-shaped and up to 10 cm in diameter; stem twining to the right, terete and slender, glabrous but near base often with curved prickles, yellow to brown. Upper leaves opposite, papery to thinly leatherly, elliptic-ovate or elliptic-lanceolate, 8-14 cm x 2-5 cm, rounded to obtuse at base, up to 9-nerved; petioles 1.5-4 cm long, slender. Male flowers in axillary panicles composed of spikes, or in simple spikes up to 8 cm long, 6-merous, small; female flowers in axillary pendant spikes up to 10 cm long, each flower with an inferior 3-loculed ovary and 3 bifid stigmas. Fruit a 3-valved winged capsule, 1.5-2.5 cm x 2.5-4 cm, shortly stipitate, retuse at apex. Seeds winged. In the literature, dye-yam is sometimes errorneously reported for the Philippines. This mistake probably arose because Knuth (1924) mistakenly cited D. cirrhosa specimens for the Philippines instead of D. merrillii Prain & Burkill

Dye-yam occurs naturally in thickets and secondary forests, usually in the lowland, in southern China up to 1500 m altitude. It is sometimes not clear whether plants are truly wild or have escaped from cultivation and naturalized, as is often the case with other Dioscorea species.

Dye-yam is a native of north-eastern Thailand, Laos, Vietnam, south-eastern China (Provinces Guangxi and Guangdong), Hong Kong, Taiwan, and the southern Ryukyu Islands. Throughout this area it is sometimes also cultivated.

Plants can easily be propagated by tubers, which are planted near trees in the forest or in waste land, using sticks as staking material. Tubers are usually collected from plants in the wild.

Tannin or dyestuff: The tubers are widely used as a source of a reddish-brown dye for colouring cloth, and as a source of a tanning material for toughening fishing nets or to prepare leather from hides. In southern China cotton cloth and grass cloth made of ramie (Boehmeria nivea (L.) Gaudich.), as well as silk, are dyed with a solution of the tubers. In Indo-China cottons are dyed with dye-yam.