Prostrate, spreading, wiry weed often rooting at the joints. Leaves narrowly ovate or elliptic 1.5-4 cm long, 0.5-1.5 cm wide, 4-5 times longer than wide, tip pointed, branch leaves about half the size of stem leaves. Perianth 3-4 mm long, cut to about two thirds its length; summer and autumn. Nut dark brown 1.5-1.8 mm long.

Europe

A weed of waste places and open ground.

 

P. arenastrum Boreau, Hogweed or Wireweed, is similar but less common; it has all leaves of the same size and the perianth divided for about half its length and tapering gradually (not abruptly) at the base.

Source: Spencer, R. (1997). Polygonaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.