Description from Flora of China
Allamanda hendersonii Bulliard ex Dombrain; A. cathartica var. hendersonii (Bulliard ex Dombrain) L. H. Bailey & Raffill.
Shrubs trailing, to 4 m, with white latex. Stems glabrous. Leaves opposite or in whorls of 3-5; petiole ca. 5 mm; leaf blade obovate, narrowly obovate, or oblong, 6-15 X 4-5 cm, glabrous or villous along veins on abaxial surface, lateral veins flattened. Peduncle short. Flowers 7-14 cm. Corolla yellow; tube 4-8 cm, funnelform, cylindric in proximal half, campanulate in distal half, limb 9-14 cm in diam.; lobes obovate-truncate to orbicular. Capsules subglobose, 3-7 X 3-5 cm, with spines to 1 cm. Seeds compressed, winged or with a membranous margin. Fl. spring-summer. 2n = 18.
Cultivated for medicine.
Fujian, Guangdong, Guangxi, Hainan, Taiwan [native to South America]