Family - Polygonaceae

Stems - To 1.5m tall, herbaceous, erect, typically simple to branching above, rhizomatous, glabrous below, densely antrorse pubescent above, reddish-green.

Leaves - Alternate, sheathing, petiolate. Ocrea large, antrorse appressed pubescent, NOT fringed at apex. Petiole to 2.5cm long, antrorse appressed pubescent, from around the midpoint of the ocrea. Blade to -20cm long, -6cm broad, entire, often undulate, sericeous, rounded to sub-cordate at base, acuminate, lanceolate to lance-elliptic or lance-ovate.

Inflorescence - Dense terminal spikes to +6cm long, 1.4cm in diameter, erect. Peduncles dense antrorse pubescent. Ocreolae fringed and pubescent, +/-1mm long.

Flowers - Perinath segments 5, rose-pink, to -4mm long, glabrous. Stamens typically 5, adnate at base of perianth segments. Filaments .5mm long, glabrous. Anthers pink, .6mm long. Styles 2, united in lower half, free above, well exserted, whitish-pink, 4-5mm long, glabrous. Stigmas capitate. Ovary compressed, glabrous, reddish-green, 1mm in diameter. Mature achene to 2.5mm in diameter, dark, shiny.

Flowering - June - October.

Habitat - Pond and lake margins, stream banks, wet meadows, roadside ditches, railroads.

Origin - Native to U.S.

Other info. - This is an attractive species can be found scattered throughout Missouri but is apparently absent from many of the counties in the Ozark region of the state. This is a variable and somewhat confusing species with many growth forms.
This is what the aquatic form looks like:

Plant.

Flowers.

Photographs taken at the Kansas City Zoo, 7-24-00, and in the Pictured Rocks National Seashore, MI., 7-21-03.