Description from Flora of China
Asclepias tenacissima Roxburgh, Pl. Coromandel 3: 35. 1819; Gymnema tenacissima (Roxburgh) Sprengel.
Lianas robust, densely pilose to tomentose throughout except for interior of corolla. Petiole 5-6 cm, slender; leaf blade ovate, 8-10 × 6-6.5 cm, base deeply cordate with rounded sinus, apex acuminate; basal veins 5-7, lateral veins 2 or 3 pairs. Inflorescences much branched, broader than long, to 8 × 12 cm, many flowered; peduncle to 2 cm, shorter than first internode. Pedicel 6-8 mm. Sepals elliptic-lanceolate, ca. 3 × 1-1.3 mm, tip rounded. Corolla "yellow," campanulate, with spreading lobes, very densely pilose outside; tube ca. 3.5 × 2.5 mm, interior retrorsely pilose toward base; lobes oblong, ca. 4 × 2.2 mm, apex rounded, minutely velvety. Corona lobes exserted from corolla tube, oblong, apex truncate-emarginate with corners produced into short horns, sometimes toothed between these. Anther appendages oblong, slightly longer than corona lobes; pollinia curved cylindric. Stigma head broadly cylindric, concealed by anther appendages.
The stems yield very strong fibers, reputedly among the strongest produced by any plant, that are used for making cords and strings.
Cliffs; ca. 1500 m. Yunnan (Szemoo) [Cambodia, India, Laos, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam]