Description from Flora of China
Herbs annual. Stems decumbent, rarely erect, 40-60 cm tall, slender, much branched, glabrous. Petiole very short or nearly absent; leaf blade narrowly lanceolate, 3-6 cm × 3-5 mm, sparsely pubescent, midvein prominent abaxially, lateral veins inconspicuous on both surfaces, base cuneate, broadly cuneate, or rounded, margin entire, not ciliate, apex acute; ocrea tubular, 8-10 mm, membranous, sparsely appressed hispidulous, apex truncate, cilia 0.5-3 mm. Inflorescence terminal or axillary, spicate, erect, lax, 3-5 cm, slender, interrupted below; bracts funnel-shaped, glabrous, margin ciliate, each 1- or 2-flowered. Perianth pinkish, 5-parted; tepals narrowly elliptic, 1.5-2 mm. Stamens 5. Styles 2. Achenes equaling persistent perianth, black, shiny, ovoid, biconvex, 1.2-2 mm, smooth. 2n = 20.
Water sides, streamsides, along ditches; sea level to 700 m. Anhui, Heilongjiang, Jiangsu, Jilin, Liaoning, ?Nei Mongol, ?Taiwan [Japan, Korea, Russia].