Description from Flora of China
Herbs annual, 8-30 cm tall. Stem richly branched at base; branches erect or obliquely ascending, densely glandular hairy and puberulous. Stipules 2-fid, ca. 2 mm, submembranous, lobes lanceolate, margin laciniate-denticulate; leaf blade oblanceolate, obovate-lanceolate, or narrowly elliptic, 0.6-2 cm × 2-8 mm, abaxially puberulous and sparsely glandular hairy on veins, adaxially sparsely puberulous or glabrous, base oblique or attenuate, margin serrate, apex acute. Flowers numerous and clustered in leaf axils, small; pedicel 1-2 mm. Sepals narrowly ovate, 1-2 mm, abaxially often villous and glandular hairy, margin membranous, apex acuminate. Petals reddish, narrowly ovate or elliptic, subequaling sepals, apex mucronate. Stamens 5; filaments filiform, base slightly widened. Ovary ovoid; styles 5; stigmas capitate. Capsule subglobose, ca. 2 mm in diam., 5-septicidal. Seeds brown, narrowly ovoid, ca. 0.5 mm, inconspicuously reticulate-striate.
Grassy places along streams, paddy field margins, roadsides. Guangdong, Guangxi, Hainan, Hunan, Taiwan, Yunnan [Laos, Indonesia, Nepal, Tajikistan, Thailand, Vietnam, and probably elsewhere in tropical Asia; tropical Africa, Australia].