Kansas Wildflowers and Grasses

SWAMP SMARTWEED

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Polygonum amphibium L. var. emersum Michx.

Ottawa County, Kansas

Perennial

Height: Up to 40 inches

Family: Polygonaceae - Buckwheat Family

Flowering Period: July, August, September

Stems:

Erect or lax, single or branched upward, glabrous or strigous, paper-like sheaths at leaf bases.

Leaves:

Variable, alternate, simple, rust-colored with age, ovate-lanceolate to oblong-lanceolate, 1 to 10 inches long and up to 2.5 inches wide, glabrous to stiff-hairy, usually not reduced above; margins often undulate; tips tapering to points; stalks .5 to 2.8 inch long; stipules entire.

Inflorescences:

Spikes, 1 or rarely 2, erect, cylindrical, 1 to 6 inches long, dense, terminal on stem.

Flowers:

Perianth, 1/6 to 1/5 inch long, pink or rose; perianth segments 5, united, tips free; stamens 8, different length from styles, extending beyond perianth lobes; styles 2.

Fruits:

Achene, egg-shaped to round, lens-shaped, 1/10 inch long, dark glossy; seed 1, small.

Habitat:

Low, wet areas of roadside ditches and crop fields, and along stream banks and the shorelines of ponds and marshes.

Distribution:

Throughout Kansas, but more frequently in eastern 1/2.

Uses:

The seeds are eaten by waterfowl and racoons. Native Americans used young shoots of swamp smartweed as a relish in the springtime, the roots to treat mouth sores, and the plant to brew a tea for stomachaches.

Comments:

Reproduces by rhizomes, so it occurs in patches.

Swamp smartweed leaves