Description from Flora of China
Melochia cordata N. L. Burman, Fl. Indica, 143. 1768; Sida humilis Cavanilles; S. humilis var. veronicifolia (Lamarck) Masters; S. multicaulis Cavanilles; S. veronicifolia Lamarck; S. veronicifolia var. humilis (Cavanilles) K. Schumann; S. veronicifolia var. multicaulis (Cavanilles) E. G. Baker.
Subshrubs procumbent, to 1 m. Stems slender, with simple pilose hairs, stiffly stellate hairs, and sometimes small simple multicellular hairs. Stipule filiform, 2-3 mm, sparsely pilose; petiole 1-3 cm, with conspicuous long simple hairs; leaf blade broadly ovate, (1-)2-5 × 1.8-4.5 cm, both surfaces stellate puberulent and ± apressed pilose, base cordate, margin crenate or dentate, apex acuminate. Flowers usually solitary, axillary, often on leafy, racemelike, axillary shoots. Pedicel slender, 1.5-4 cm, articulate on distal part, sparsely stellate and with long hairs. Calyx cup-shaped, 4-6 mm, sparsely pilose with long hairs, lobes 2-3 mm, acute. Corolla yellow, 8-9 mm in diam. Filament tube ca. 2 mm, glabrous or sparsely pilose. Schizocarp nearly globose, ca. 3 mm in diam.; mericarps 5, ovoid-tetrahedral, ca. 2.5 mm, smooth, glabrous or sparsely minutely hairy at apex, apex not beaked, not awned. Fl. Jul-Feb.
Sida cordata var. nasirii Abedin was erected for a group of specimens from Pakistan with distinctive, very slender, purple pedicels.
Scrub, grassy roadsides. Fujian, Guangdong, Guangxi, Hainan, Taiwan, Yunnan [India, Philippines, Sri Lanka, Thailand; pantropical species of unknown origin].