Sub-category: Smartweed family
Syn. Polygonum sagittatum. Weak-stemmed sprawling annuals. They use backward-pointing hooks on the stem and leaves to help it climb over other plants. An annual herb up to 200 cm tall, with prickles along the stem. Leaves are up to 10 cm long, heart-shaped or arrowhead-shaped (unusual for the genus). Flowers are white to pink, borne in spherical to elongated clusters up to 15 mm long.
It grows in moist areas along lake shores, stream banks, marshes, and wet thickets.