Apocynum juventas Loureiro, Fl. Cochinch. 1: 167. 1790; Streptocaulon griffithii J. D. Hooker; S. tomentosum Wight & Arnott.

Lianas to 8 m, densely tawny pilose except for corolla. Petiole 3-7 mm; leaf blade obovate or broadly elliptic, 7-15 × 3-9.5 cm, leathery or thick papery, base rounded to cordate, apex acute or rounded and apiculate; lateral veins 14-20 pairs, subparallel. Inflorescences 4-20 cm, sometimes thyrsoid; sessile or with peduncle to 8 cm; flowers densely clustered in young inflorescences. Flower buds subglobose to ovoid, ca. 3 × 3 mm. Sepals ovate, ca. 1.3 × 1 mm, acute. Corolla yellow-green outside, yellow-brown inside, glabrous; tube short; lobes ovate, ca. 3 × 1.5 mm. Corona lobes longer than anthers. Ovaries densely pubescent. Follicles oblong or oblong-lanceolate in outline, 7-13 cm × 5-10 mm, horizontal. Seeds oblong, 6-9 × 2-3 mm; coma 3-3.5 cm. Fl. May-Oct, fr. Aug-Dec.

The roots are used medicinally for the treatment of dysentery and stomachache, and the leaves are used externally for the treatment of snake poisoning and abscesses.

Montane forests, thickets, often clinging to trees; 300-1000 m. Guangxi, Guizhou, Yunnan [Cambodia, India, ?Indonesia, Laos, Myanmar, Thailand, Vietnam]