Polygonum aviculare L.

Polygonum aviculare L.





Vernacular Names


Knot grass, prostrate knot weed, wire weed.


Bi[eef]n s[us]c, rau d[aws]ng.


Renouée des oiseaux.

Geographical Distributions

Polygonum aviculare is native to Europe and northern Asia, now widely distributed in temperate, subtropical and tropical regions, including Vietnam and Malesia.


Polygonum aviculare is an annual, very variable, procum­bent or ascending herb and it can grow up to 10-80 cm tall. The stems are much branched, grooved and smooth.

The leaves are arranged alternate, simple, oblance-shaped to elliptical, measure 0.7-1.5 cm x 0.2­0.5 cm, wedge-shaped at base, acuminate to acute at apex, hairless on both surfaces, papillose and subsessile. The ocrea is 2-5 mm long, hairless, conspicuously veined and lacerate at the up­per margin.

The inflorescence is an axillary, with 3-6-flowered fascicle, often hidden in ocrea, with lacerate bracts and hairless. The flowers are with short, jointed pedicel, actinomorphic, bisexual, small, with 5 perianth segments, 2-3 mm long elliptically, acute at apex, with one main vein per tepal, sometimes branched and white to pink. There are 8 stamens. The filaments are flattened, swol­len at base, dilated, with ovate anthers and small. The interstaminal nectaries are absent. The ovary is superior, 1-ovulate and with 3-partite styles.

The fruit is a trigonous nutlet, 2-3 mm long, puncticulate, dark brown and dull. The seedling is with epigeal germination.

Ecology / Cultivation

Polygonum aviculare occurs in tropical regions in meadows and river banks, but in the temperate zone, it is a weedy species. It is found from sea lev­el up to 3600 m altitude.

Line Drawing / Photograph



  1. Plant Resources of South-East Asia No.12(2): Medicinal and poisonous plants 2.