2. Calotropis procera (Aiton) W. T. Aiton, Hortus Kew. ed. 2. 2: 78. 1811.
白花牛角瓜 bai hua niu jiao gua
Asclepias procera Aiton, Hort. Kew. 1: 305. 1789; A. gigantea Jacquin, not Linnaeus.
Shrubs or small trees to 6 m tall. Petiole very short; leaf blade grayish green or hoary white, ovate to obovate, 10-30 × 5-15 cm, base cordate, apex abruptly pointed. Cymes umbel-like, 3-10-flowered, finely woolly; peduncle 2-5.5 cm. Pedicel 1.5-2.5 cm. Sepals elliptic or ovate, ca. 5 × 3 mm. Flower buds subglobose. Corolla white outside, pinkish inside, 1.5-2 cm in diam.; lobes with purple-brown apices, broadly ovate or ovate-triangular, 7-10 × 6-10 mm, spreading. Corona as long as gynostegium. Follicles subglobose to obliquely ovoid, inflated, 6-10 × 3-7 cm, pericarp thick, spongy. Seeds ca. 6 × 4 mm; coma 3.5-5 cm. Fl. May-Dec. 2n = 22.
Cultivated for medicine in S Guangdong, Guangxi, S Yunnan [Afghanistan, India, Myanmar, Nepal, Pakistan, Thailand, Vietnam; Africa, SW Asia, introduced to Australia and Central and South America]
The bark and leaves are used for the treatment of leprosy and asthma, respectively.