Description from Flora of China
Convolvulus purpureus Linnaeus, Sp. Pl. ed. 2. 1: 219. 1762; Ipomoea chanetii H. Léveillé; I. hispida Zuccarini; Pharbitis hispida Choisy; P. purpurea (Linnaeus) Voigt.
Herbs annual, twining; axial parts short pubescent and long retrorse hirsute. Stems 2-3 m. Petiole 2-12 cm; leaf blade circular-ovate or broadly ovate, 4-18 X 3.5-16.5 cm, ± strigose, base cordate, margin entire or ± 3-lobed, apex acute or ± abruptly acuminate. Inflorescences 1-5-flowered; pedun-cle 4-12 cm; bracts linear, 6-7 mm, spreading hirsute. Pedicel recurved before and after anthesis, 1.2-1.5 cm. Sepals subequal, 1.1-1.6 cm, spreading hirsute abaxially in basal 1/2; outer 3 oblong, apex acuminate; inner 2 linear-lanceolate. Corolla red, reddish purple, or blue-purple, with a fading to white center, funnelform, 4-6 cm, glabrous. Stamens included, unequal; filaments pubescent basally. Pistil included; ovary glabrous, 3-loculed. Stigma 3-lobed. Capsule subglobose, 9-10 mm in diam., 3-valved. Seeds black or straw colored, ovoid-trigonous, glabrous or hilum sparsely pilose. 2n = 30, 32.
The seeds are used medicinally.
Waysides, hedges, fields; 0-2800 m, cultivated or escaped. Most provinces of China [Indonesia, Nepal, Pakistan, Philippines, Sri Lanka; native of North and South America, introduced and naturalized worldwide]