Sida corylifolia Wallich ex Masters.

Subshrubs erect, 1-2 m tall; most parts sparsely stellate puberulent, simple hairs absent. Stipule filiform, 3-4 mm; petiole 2-6 cm; leaf blade orbicular or ovate, 5-10 × 3-7.5 cm, base rounded, margin minutely crenate, apex shortly acuminate. Flowers mostly subterminal, in umbel-like terminal clusters, often on reduced axillary, 2-7 cm shoots. Pedicel 0.6-2.5 cm, articulate at middle, sparsely stellate pilose. Calyx 8-11 mm, sparsely stellate pilose, lobes 5, triangular. Corolla yellow, 2-3.5 cm in diam.; petals 5, obovate, ca. 1.2 cm. Filament tube ca. 1 cm, glabrous, filaments numerous, slender, ca. 3 mm. Style branches 8-9. Schizocarp nearly globose; mericarps 8 or 9, with vertical grooves, apex 2-awned, exceeding calyx, awn 3-6 mm, retrorsely hispid. Seeds ovoid, apex densely brown puberulent. Fl. winter-spring.

Sida subcordata is very variable in leaf shape and density of indumentum, but the combination of the large leaves and flowers and conspicuously retrorsely hispid mericarp awns is diagnostic. Borssum Waalkes (Blumea 14: 202. 1964) speculated that the species may have arisen through hybridization between S. rhombifolia Linnaeus and S. cordifolia Linnaeus, but this needs to be verified.

The entire plant is used medicinally.

Margins of open forests, grasslands, roadsides. Guangdong, Guangxi, Hainan, Yunnan [India, Indonesia, Laos, Myanmar, Thailand, Vietnam].