Dioscorea angusta R.Knuth
Dioscorea bonnetii A.Chev.
Dioscorea camphorifolia Uline ex R.Knuth
Dioscorea intempestiva Prain & Burkill
Dioscorea matsudae Hayata
Dioscorea rhipogonoides Oliv.
Common Name: Dyeing Yam
Dyeing yam is a dioecious, perennial plant producing annual, climbing stems about 10 metres long from a tuberous rhizome[
]. These stems scramble over the ground, or twine into the surrounding vegetation[
]. The stems twine to the right[
Formerly traded internationally as an important source of tannins for use as a preservative and dye, nowadays it is only of local importance, but is still cultivated in S China, Taiwan and North Vietnam[
E. Asia - southern China, Laos, Thailand, Vietnam.
Thickets and secondary forests, usually in the lowland, but in southern China up to elevations of 1,500 metres[
|Cultivation Status||Cultivated, Wild
The tuber is edible[
The tubers contain 6 - 13% tannin[
]. This is used for preserving nets and leather as well as for colouring clothes made from ramie, silk and cotton a brown colour[
The tubers are harvested when about 3 years old, the harvesting taking place in the dry season when the red flesh has a high tannin content[
]. The tubers should be harvested with care to ensure that they are not broken or bruised. They should be protected against desiccation because they lose much of their colouring properties when desiccated[
]. For dyeing and tanning purposes, the tuber are peeled and the flesh is rasped[
]. About 3 litres of water is added to 1 kg of rasped flesh, and clothes or nets are dipped in the hot or cold solution remaining after filtering, and afterwards dried in the sun[
]. This handling is repeated several times, until the desired reddish-brown colour is attained[
]. The dye rapidly loses its activity, and best results are obtained with fresh solutions[
]. Mordants such as alum, aluminium acetate and bichromate are often added to the solution, but sometimes leaves of Psidium guajava L. and Piper betle L., or mud (in China) replace the mordant[
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