Dioscorea deltoidea Wall. ex Griseb.

The tubers contain saponin, acrid resin, diosgenin, starch and calcium oxalate. They are used for washing shawls and woolen cloth as well as a vermifuge and an anthelmintic for purging out intestinal worms. Diosgenin is said to be a basic material for hormone preparation.

Dioscorea deltoidea var. orbiculata Prain & Burkill (Ann. Roy. Bot. Gard. (Calcutta) 14: 25. 1936) was published for a Chinese collection with the capsule ± globose. However, the description lacked a Latin diagnosis so the name is invalid. Chinese material often differs from typical, Indian material by the distinctly 3-lobed leaves, but the separation is not very clear-cut and more detailed investigations should be undertaken to clarify the status of these plants.

Tubers ligneous, irregular. Stems glabrous, twining clockwise. Leaves alternate, simple, 5-11.5 cm long, 4-10.5 cm broad, ovate or subdeltoid-ovate, often cordate, the basal lobes rounded or sometimes dilated outwards, 7-9-nerved, acuminate, glabrous above, pubescent on the nerves beneath; petiole 5-10 cm long, slender. Male spikes solitary, axillary, simple or sometimes branched, slender, lax, 7.5-25 cm long; flowers in small distant clusters; stamens 6, antheriferous. Female spikes solitary, slender, up to 15 cm long, few-flowered. Capsule 2 cm long, 3 cm broad, obovate or obcordate. Seeds winged unequally all round.

Rhizome horizontal, ginger-shaped, 1.2--1.5 cm thick. Stem twining to left, drying light brown to purplish brown, grooved. Leaves alternate, simple; petiole 4--10(--15) cm; leaf blade drying gray-green, triangular or triangular-ovate, usually 3-lobed, 5--9 × 4--5.5 cm, adaxially glabrous, abaxially papillose-setulose along veins, basal veins 3--7, outermost ones much shorter, base shallowly cordate (with very broad sinus) to subtruncate, apex of middle lobe acuminate, apex of lateral lobes rounded. Male spike solitary, sometimes branched, 9--16 cm. Male flowers: solitary or paired, sessile; bracts broadly ovate, membranous, apex acute; perianth saucer-shaped, 3--3.5 mm in diam., lobes ovate, ca. 0.8 mm wide; stamens 6, inserted at base of perianth, anthers 3 introrse and 3 extrorse, connectives not fork-shaped. Female spike to 5 cm, 4--6-flowered. Female flowers: staminodes present. Capsule reflexed, brown at maturity, purplish brown spotted, globose or oblong-obovoid, (1.5--)1.8--2.2 cm, base rounded, apex emarginate or rounded; wings (0.7--)1.2--1.4 cm wide. Seeds inserted near middle of capsule, ovate, winged all round. Fl. May--Jun, fr. Jun--Sep.

Himalaya (Kashmir to Assam), Indo-China, W. China.

Distribution: Afghanistan, W. Pakistan and throughout the Himalayas.

Very common from 3000-1000 ft. in Kashmir and Swat.

Sichuan, Xizang, Yunnan [Bhutan, India, Myanmar, Nepal, Sikkim, Thailand, Vietnam].

450-3100 m

Fl. Per.: May- July.

Broad-leaved forests, scrub forests; 2000--3100 m.

Dioscorea deltoidea, the Nepal yam, is a species of flowering plant in the family Dioscoreaceae. Its native range is the Himalayas through to south-central China and mainland Southeast Asia. Its tubers contain diosgenin and are harvested by local peoples as a treatment for a variety of conditions, including gastrointestinal disorders and intestinal worms. Tubers are also eaten after boiling, washing, and baking. It grows in forests and humus-rich soils.

Dioscorea deltoidea là một loài thực vật có hoa trong họ Dioscoreaceae. Loài này được Wall. ex Griseb. mô tả khoa học đầu tiên năm 1842.

三角叶薯蓣（学名：Dioscorea deltoidea）是薯蓣科薯蓣属的植物。分布于印度、老挝、尼泊尔、巴基斯坦、阿富汗以及中国大陆的西藏等地，生长于海拔2,000米至4,000米的地区，常生于灌木丛中以及沟谷阔叶林中，目前尚未由人工引种栽培。