Perennial by long rootstocks, rooting in the mud or in the water, stem erect, glabrous, or somewhat pubescent, enlarged at the nodes, 1 to 3 feet high. Leaves ovate-lanceolate or oblong-lanceolate, the upper ones often narrower, 2 to 8 inches long, acute or acuminate at the apex, rounded or cordate at the base, petioled, ocreae cylindric, becoming loose, not ciliate. Flowers in linear-oblong, dense, terminal racemes, 1 to 3 inches long; calyx dark rose-colored, five-parted; stamens five in number.
Memoir 15 N. Y. State Museum
A. Swamp Smartweed - Persicaria muhlenbergii b. ladys-thumb; heartweed Persicaria persicaria