smartweed

Any of various plants of the genera Persicaria and Polygonum, having sheathlike stipules and small, densely clustered pink, white, or green flowers.

The water-pepper, Polygonum Hydropiper, a weed of wet places in the Old World and the New.

An acrid plant of the genus Polygonum (P. Hydropiper), which produces smarting if applied where the skin is tender.

Any of more than a dozen species of the genus Polygonum.