2. Hoya pottsii Traill, Trans. Hort. Soc. London. 7: 25. 1830.
铁草鞋 san mai qiu lan
Hoya angustifolia Traill; H. obscurinervia Merrill; H. pottsii var. angustifolia (Traill) Tsiang & P. T. Li.
Plants glabrous except for corolla. Stems mostly climbing, to 4 m or more. Petiole 0.5-2 cm; leaf blade ovate-oblong to oblong-lanceolate, 6-12 × 3-6 cm, thin leathery when dry, base rounded, subcordate, acute, or cuneate, apex acute; basal veins 3, extending more than halfway along blade. Inflorescences extra-axillary, globose; peduncle (2-)5-10 cm. Pedicel 1-1.5 cm. Sepals ovate, ca. 1.5 × 0.8 mm. Corolla white with reddish center, up to 1 cm in diam., reflexed; lobes broadly ovate, glabrous outside, slightly villous inside. Corona lobes stellate spreading, outer angle acute, margin strongly reflexed to enclose a hollow space, inner angle acute, incumbent over stigma head. Follicles linear-oblong, ca. 11 cm × 8 mm. Seeds linear-oblong ca. 4 × 1 mm; coma ca. 3.5 cm. Fl. Apr-May, fr. Aug-Oct.
* Dense forests, on tree trunks or rocks; 0-500 m. Guangdong, Guangxi, Hainan, Taiwan, Yunnan
The leaves are used for the treatment of fractures and swellings and for draining off pus and promoting new growth.