1. Calotropis gigantea (Linnaeus) W. T. Aiton, Hortus Kew. ed. 2. 2: 78. 1811.
牛角瓜 niu jiao gua
Asclepias gigantea Linnaeus, Sp. Pl. 1: 214. 1753; Periploca cochinchinensis Loureiro; Streptocaulon cochinchinense (Loureiro) G. Don.
Shrubs 1-5 m tall. Petiole 1-4 mm; leaf blade obovate-oblong or oblong, 7-30 × 3-15 cm, base cordate, apex obtuse, cottony tomentose when young, frequently glabrescent and glaucous green; lateral veins 4-8 pairs. Cymes umbel-like, with fine woolly hairs; peduncle robust, 5-12 cm. Pedicel thick, 2-5 cm. Calyx almost flat, 1.2-1.5 cm in diam. Flower buds cylindric. Corolla usually purplish or lilac with paler greenish base, 2.5-3.5 cm in diam., fleshy, glabrous; lobes ovate, 1-1.5 × 0.6-1 cm, spreading or reflexed, margin revolute. Corona shorter than gynostegium. Follicles obliquely elliptic to oblong-lanceolate in outline, 5-10 × 2.5-4 cm, both ends incurved. Seeds broadly ovate, 5-7 × 3-4 mm; coma 2.5-4 cm. Fl. almost throughout the year. 2n = 22.
Woods of dry areas, stream banks; 0-1400 m. Guangdong, Guangxi, Hainan, Sichuan, Yunnan [India, Indonesia, Laos, Malaysia, Myanmar, Nepal, Pakistan, Sri Lanka, Thailand, Vietnam; tropical Africa]
The bark is used as a medicine for the treatment of neurodermatitis and syphilis, and the leaves are used as a poultice. The juice is used in making a yellow dye and in tanning. A fine fiber is obtained from the stems.