Prostrate knotweed

Description
Annual, seed-propagated weed with spindle-shaped root. Depending on location P. aviculare is extremely various in habit and leaf form.

Characteristic Features
Prostrate growth, mostly branching from base, small leaves.

Cotyledons
Very long, evenly slender, bluntly pointed.

Stems
Usually prostrate, heavily ramified, leaves at the nodes up to the tip, up to 50 cm (19.5 inch) long.

Leaves
Elliptical or lanceolate to linear, pinnate-nerved, hardly petiolate, emerging from a thin, membranous, stalk-enclosing, incised tube (stipule sheath).