Xu Chang Qing

Cynanchum paniculatum is a slender perennial herb of the family Apocynaceae (formerly Asclepiadaceae), native to dry, sunny grassy slopes, open woodland margins, and rocky meadows across China, Korea, Japan, and the Russian Far East. It grows 50 to 80 cm tall from a short, knotty rhizome bearing many slender, fibrous roots; the rhizome and root system together emit a distinctive aromatic odor when crushed. The stems are erect, mostly unbranched, and nearly glabrous, bearing opposite, narrowly linear-lanceolate leaves 5 to 13 cm long with entire margins. Loose terminal and axillary cymose panicles of small, pale yellow-green to brownish star-shaped flowers appear in summer, followed by paired, narrow follicles releasing comose seeds. The rhizome with attached roots is harvested in autumn for use.