Polygonum L.

Stipules deeply cut, silvery to white Polygonum
Leaves linear-oblong, 3–15 mm long, only the midvein conspicuous underneath. Perianth c. 1 mm long with a very short tube. Stems usually less than 20 cm long. Widespread. Can be a weed in pastures and gardens. Small Knotweed Polygonum plebeium
Leaves oblong-lanceolate or elliptic, 1–4 cm long; lateral veins conspicuous underneath. Nut dull. Stems up to 1 m long