Description from Flora of China
Herbs ascending to decumbent, perennial, rhizomatous and sometimes suffrutescent from woody caudex, rarely with basal rosette. Stems 7-65 cm, simple or branched, strigillose, sometimes with longer spreading hairs. Leaves green, with inconspicuous veins, glabrous to sparsely strigillose; petioles 3-20 mm; basal blade 2-5 × 0.5-2 cm; cauline blade elliptic to oblanceolate or oblong-ovate, 1-6 × 0.4-2.5 cm, base attenuate, margin subentire to coarsely dentate, sometimes sinuate-pinnatifid at leaf base, apex acute to obtuse. Inflorescence a lax open simple raceme. Flowers open near sunrise; floral tube 4-10 mm. Sepals 5-10 mm, with free tips 0.4-1 mm. Petals pink to rose-purple, 5-12 mm. Anthers 2-3.5 mm; pollen ca. 50% fertile. Ovary usually densely strigillose; stigma surrounded by anthers. Capsules clavate or narrowly obovoid, 4-12 mm, valves angled or weakly winged, attenuate to slender sterile stipe (pedicel) 5-20 mm. Seeds in several indistinct rows per locule, brown with dark spot at each end, obovoid, 0.5-1.2 mm, finely papillose. Fl. May-Nov, fr. Jun-Dec. 2n = 14, permanent translocation heterozygote; self-compatible, autogamous.
Disturbed habitats along creeks and in low weedy places; 1000-2000 m. Guizhou, Jiangxi, Sichuan, Yunnan, Zhejiang [Japan; native to S North America and N South America, frequently cultivated and naturalized in SW Asia, Australia, Europe, and South America].