Botanical Name: Discoria deltoides
Species: D. deltoidea
Synonyms: Tamus nepalensis Jacquem. ex Prain & Burkill
Common Names: Yam or Nepal yam, Lady’s Cushion, Maiden Pink, Meadow Pink. *Yam or Nepal yam, Lady’s Cushion, Maiden Pink, Meadow Pink, *Hindi: Shingli-mingli, Baniatakari, Harvish, Janj, Jung kinch • Nepali: Bhyakur tarul
Habitat: Discoria deltoides is native range is the Himalayas through to south-central China and mainland Southeast Asia. It is found in the Himalayas, from Kashmir to Assam, Indo-China and W. China, at altitudes of 450-3100 m. It grows in forests and humus-rich soils.
Discoria deltoides is a hairless vine, twining clockwise. Tubers are ligneous, irregular. Alternately arranged leaves are simple, 5-11.5 cm long, 4-10.5 cm broad, ovate or triangular-ovate, often heart-shaped, the basal lobes rounded or sometimes dilated outwards, 7-9-nerved, long-pointed, hairless above, velvety on the nerves beneath. Leaf-stalks are 5-10 cm long, slender. Male flower spikes occur solitary in leaf axils, simple or sometimes branched, slender, lax, 7.5-25 cm long. Flowers are in small distant clusters; stamens 6, antheriferous. Female spikes are solitary, slender, up to 15 cm long, few-flowered. Capsule is 2 cm long, 3 cm broad, obovate or obcordate. Seeds are winged unequally all round. It produces many blooms in shades of red, pink, lavender or white with a darker star-like ring near the center.Flowering during May-July.
Easily grown in a fertile well-drained soil in a sunny position or light shade. Prefers a rich light soil. Plants produce tubercles (small tubers that are formed in the leaf axils of the stems), and can be propagated by this means. A climbing plant that supports itself by twining around the branches of other plants. Dioecious. Male and female plants must be grown if seed is required.
Through seeds – sow March to April in a sunny position in a warm greenhouse and only just cover. It germinates in 1 – 3 weeks at 20°c. Prick out the seedlings as soon as they are large enough to handle and grow on in a greenhouse for their first year. Plant out in late spring as the plant comes into new growth. Basal stem cuttings in the summer. Division in the dormant season, never when in growth. The plant will often produce a number of shoots, the top 5 – 10 cm of the root below each shoot can be potted up to form a new plant whilst the lower part of the root can possibly be eaten. Tubercles (baby tubers) are formed in the leaf axils. These are harvested in late summer and early autumn when about the size of a pea and coming away easily from the plant. They should be potted up immediately in individual pots in a greenhouse or cold frame. Plant out in early summer when in active growth.
Tubers are edible – cooked and eaten. A slightly bitter flavour, it is usually boiled with some wood ash in order to remove the bitterness. Some caution is advised. See notes below on other uses of the root and above on toxicity.
The juice of the root tuber istaken in the evening in the treatment of roundworm. It is also used to alleviate constipation. The roots of most, if not all, members of this genus, contains diosgenin. This is widely used in modern medicine in order to manufacture progesterone and other steroid drugs. These are used as contraceptives and in the treatment of various disorders of the genitary organs as well as in a host of other diseases such as asthma and arthritis. The roots of this species contain an average of 4.8% diosgenin.
Other Uses: A soap is obtained from the tuber. This soap is due to the presence of poisonous saponins in the root. The soap is also used as a body wash to kill lice. This plant provides excellent groundcover for landscapes .
Known Hazards : Edible species of Dioscorea have opposite leaves whilst poisonous species have alternate leaves.