Family: Polygonaceae Arable Knotgrass Polygonum agrestinum Flowering time Habitat Part of the Polygonum aviculare group. Stems erect, ascending or sprawling with more than one main stem. Heterophyllus, narrow leaves 7-15 x 2-3mm and 15-20(-30) x 3-4mm, Internodes usually to 10(-20)mm. Perianth lobed nearly to base

Arable Knotgrass, Polygonum agrestinum
Photographs: Kingston Lacy, Dorset. September 2020