Identificaciones de susanhewitt

Herb about almost 2 m tall; lower stems nearly glabrous; leaf abaxials strigose, marginal nearly 1 mm long; inflorescences distinctly bent; tepal veins straight or curved, sometimes forked apically, one fork sometimes spreading, but not both; achenes with a small swelling at the base (tumescent). Growing in gravel and silt at the bottom of a drainage ditch impounded by roads.

Smallest ticks on ruler are 0.5 mm.

Compare these flowers and achenes to those of Persicaria lapathiflolia here: https://www.inaturalist.org/observations/184331562