Description from Flora of China
Asclepias cordata N. L. Burman, Fl. Indica 72, fig. 2. 1768; Cynanchum odoratissimum Loureiro; Oxystelma ovatum P. T. Li & S. Z. Huang; Pergularia minor Andrews; P. odoratissima (Loureiro) Smith; Telosma minor (Andrews) Craib; T. odoratissima (Loureiro) Coville.
Stems 1-10 m, yellowish green, pubescent when new, those of previous year pale gray, glabrescent, usually sparsely lenticellate. Petiole 1.5-5 cm; leaf blade ovate, 4-12 × 3-10 cm, base deeply cordate with narrow sinus, apex acuminate; basal veins 3, lateral veins to 6 pairs. Cymes umbel-like, 15-30-flowered; peduncle 0.5-1.5 cm, puberulent. Sepals oblong-lanceolate, puberulent. Corolla yellowish green; tube 6-10 × 4-6 mm, puberulent outside, pilose or glabrous with pilose throat inside; lobes oblong, 6-12 × 3-6 mm, ciliate. Corona lobes slightly fleshy, basal part ovate, apex acuminate, often notched to deeply lobed, internal appendage often longer than lobe proper. Pollinia oblong or reniform. Stigma head capitate. Follicles lanceolate in outline, 7-13 × 2-3.5 cm, glabrous, somewhat obtusely 4-angled. Seeds broadly ovate, ca. 1 × 1 cm, flat, apex truncate, margin membranous; coma 3-4 cm. Fl. May-Oct, fr. Oct-Dec. 2n = 22.
The flowers are very fragrant and yield perfumed oil. They are used in cooking and medicinally to treat conjunctivitis.
Material from outside China varies greatly in corolla size and shape and, to a lesser extent, in leaf shape. It is not clear whether a species complex or a single polymorphic species,
possibly including the two following species, is involved.
Open woods, bushland. Guangdong, Guangxi; cultivated elsewhere in S China [India, Kashmir, Myanmar, Pakistan, Vietnam; Europe, North and South America].