Description from Flora of China
Herbs annual. Stems erect, ascending or prostrate at base, 30-60 cm tall, branched from base, glabrous, swollen at nodes. Petiole short or nearly absent; leaf blade lanceolate or broadly lanceolate, 5-13 × 1-2 cm, abaxially appressed hispidulous along veins, adaxially glabrescent, base cuneate to rounded, margin ciliate, apex acute or acuminate; ocrea tubular, 7-8 mm, membranous, sparsely pubescent, apex truncate, cilia 6-7 mm. Inflorescence terminal or axillary, spicate, erect, 2-4 cm, interrupted; bracts funnel-shaped, glabrous, margin long ciliate, each 5- or 6-flowered. Pedicels equaling bracts, 2-2.5 mm. Perianth pink or red-purple, 5-parted; tepals elliptic, 1.5-2 mm. Stamens 6-8, included. Styles 3, connate to below middle; stigmas capitate. Achenes included in persistent perianth, black, shiny, broadly ovoid, trigonous, ca. 2 mm. Fl. May-Jun, fr. Jun-Aug.
Moist valleys, along stream banks, shaded places along ditches, water sides; sea level to 3100 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, ?Nei Mongol, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xizang, Yunnan, Zhejiang [India, Indonesia, Japan, Kashmir, Korea, Malaysia, Mongolia, Myanmar, Nepal, Philippines, Russia (Far East)].