Polygonum aviculare L.
A spreading, prostrate to erect annual, with stems between 10 and 60 cm long, and forming patches which can be up to 100 cm across. Leaves very variable in shape and size, those on the main stems larger than those on the branches; narrowly elliptical to linear, elliptical or oblanceolate; 1 to 5 cm long, and up to 2 cm wide. Sheaths with irregularly fringed edges, with brownish base; shorter than the internodes. Flowers 2 to 4 mm long, in axillary clusters of 1 to 5. Perianth segments 5, greenish with a white to pink margin. Achenes dark brown to black, about 3 mm long, three-angled, shorter or a slightly longer than the perianth.
Local: Not common in Gibraltar. Found as a weed in cultivated plots and gardens throughout Gibraltar. A plant of waste places, cultivated ground, and also roadsides and tracksides.
Global: Found throughout Europe.
Flowers from (April) May, June to July ( September)