Polygonum humifusum Mert. ex C. Koch

Herbs annual. Stems prostrate or ascending, 20-30 cm tall. Petiole very short, articulate at base; leaf blade elliptic or oblanceolate, 1-1.5 cm × 3-5 mm, abaxially with slightly prominent midvein and conspicuous lateral veins, adaxially with conspicuous midvein and inconspicuous lateral veins, base narrowly cuneate, apex slightly obtuse or acute; ocrea: lower part brownish, upper part white, membranous, 3- or 4-veined. Flowers 2-5, in axillary fascicles. Perianth green, margin white or pinkish, 5-parted to 2/3; tepals oblong, 1.5-2 mm. Achenes exceeding persistent perianth, dark brown, slightly shiny, narrowly ovoid, trigonous, 2-2.5 mm, densely minutely punctate, apex acute. Fl. Jun-Jul, fr. Aug-Sep.

Heilongjiang, Jilin, Liaoning [Mongolia, Russia; North America].

Near fields, roadsides, in sand by riversides; sea level to 400 m.

Polygonum humifusum f. yamatutae (Kitagawa) C. F. Fang; P. mandshuricum Skvortsov; P. yamatutae Kitagawa.

Polygonum humifusum is an Asian and North American species of plants in the buckwheat family. It grows in arctic and subarctic regions of eastern Russia, Mongolia, northeastern China, Alaska, and Canada (Yukon, Northwest Territory, Nunavut, British Columbia, northern Ontario).

Polygonum humifusum is a branching herb with erect or reclining stems up to 30 cm (1 foot) tall. Flowers are green, pink, or white, produced in groups of 2–5. It grows in fields and on riverbanks at elevations less than 400 m (1300 feet).