Cynanchum thesioides (Freyn) K. Schumann

Herbs suffrutescent, sometimes lianescent, rhizomatous; usually densely puberulent throughout. Stems erect or upper part twining, mainly branched at base. Leaves opposite or subopposite, rarely whorled, sessile or subsessile; leaf blade linear to linear-lanceolate, or occasionally broadly lanceolate, 3-10 × 0.2-1.5(-2.3) cm; midvein elevated abaxially, lateral veins obscure. Inflorescences umbel-like to short racemelike, sometimes terminal; cymules 2-flowered, solitary or clustered; peduncle 1-5(-20) mm. Pedicel 2-10 mm. Sepals lanceolate, 1-2.5 × 0.4-0.8 mm, puberulent, ciliate. Corolla green-white, mostly glabrous but sometimes with some hairs especially inside tube; tube 1-1.5 mm; lobes 2-3 × 1-1.5 mm, rounded. Corona cupular; tube shorter than anthers, margin 5-lobed; lobes triangular-lanceolate to linear, up to middle of anthers to higher than anther appendages, incurved at base, apex acuminate or rounded. Anther appen-dages erect, ovate-triangular to lanceolate; pollinia oblong. Stigma head depressed. Follicles ovoid-fusiform, 5-6(-7.5) × 1-2 cm. Seeds ovate, 5-9 × 3-5 mm; coma ca. 2 cm. Fl. Mar-Aug, fr. Aug-Oct.

Gansu, Hebei, Heilongjiang, Henan, Hunan, Jiangsu, Jilin, Liaoning, Nei Mongol, Shaanxi, Shandong, Shanxi, Xinjiang [Kazakhstan, Korea, Mongolia, Russia].

Open disturbed sites in thickets, dry valleys, sand dunes, grasslands, roadsides; 0-3000 m.

Vincetoxicum thesioides Freyn, Oestrr. Bot. Z. 40: 124. 1890; Alexitoxicon sibiricum (Linnaeus) Pobedimova; Antitoxicum sibiricum (Linnaeus) Pobedimova; Asclepias sibirica Linnaeus; Cynanchum sibiricum (Linnaeus) R. Brown (1810), not Willdenow (1799); C. sibiricum var. australe (Maximowicz) Maximowicz ex Komarov; C. sibiricum var. gracilentum Nakai & Kitagawa; C. sibiricum var. latifolium Kitagawa; Rhodostegiella sibirica (Linnaeus) C. Y. Wu & D. Z. Li; R. sibirica var. australis (Maximowicz) C. Y. Wu & D. Z. Li; Vincetoxicum sibiricum (Linnaeus) Decaisne; V. sibiricum var. australe Maximowicz; V. sibiricum var. boreale Maximowicz.