白首乌 bai shou wu

Asclepias hastata Bunge, Enum. Pl. China Bor. 43, n. 146. 1833, not Cynanchum hastatum Lamarck (1786); Symphyoglossum hastatum (Bunge) Turczaninow; Vincetoxi-cum hastatum (Bunge) Kuntze.

Root tubers 3-7 × 1.5-4 cm. Stems twining, to 4 m, slender, puberulent. Leaves opposite; petiole 1-1.5 cm; leaf blade hastate or narrowly ovate-triangular, 3-8 × 1-5 cm, membranous, hispid, base cordate, basal lobes rounded, recurved, apex acuminate; lateral veins 4-6 pairs. Inflorescences umbel-like, to 4 × 2.5 cm; peduncle 1.5-2.5 cm. Pedicel ca. 1 cm. Sepals lanceolate, ca. 1.5 × 0.7 mm, glabrous; basal glands present, few. Corolla white or yellowish green, rotate; tube ca. 1 mm; lobes oblong, ca. 4 × 2.5 mm, acute, strongly reflexed, minutely puberulent adaxially near center, otherwise glabrous. Corona deeply 5-lobed; lobes lanceolate, ca. 3.5 mm, longer than gynostegium, with slender, ligulate, adaxial appendage incumbent on anther. Anther appendages ovate; pollinia oblong. Follicles lanceolate in outline, 9-10 × ca. 1 cm, with 2 inconspicuous longitudinal ridges, glabrous. Seeds ovate, ca. 1 × 0.5 cm; coma ca. 4 cm. Fl. Jun-Jul, fr. Jul-Nov.

Thickets, roadsides, valleys; ca. 1500 m. Gansu, Hebei, Liaoning, Nei Mongol, Shandong, Shanxi, Zhejiang [Korea]

The root tuber is used as medicine for lumbago, neurasthenia, and insomnia. The plant is the basis of an important Chinese tonic medicine.