Persicaria amphibia (L.) Gray
Family: Polygonaceae
water heart's-ease, water smartweed
Persicaria amphibia image
Robert Bierman  
Etymology: Persicaria: peach-like, the medieval name for knotweed
Plants: erect, terrestrial or floating, perennial, aquatic forb 1'-5' tall; stems branched with usually several major stems flowering; from rhizomes
Leaves: alternate, base not jointed, up to 2 1/3" wide
Flowers: pink to red, 5-parted, 3/16" long, cup-shaped, petals and petal-like sepals bluntly rounded at the tip and connected at the base; inflorescence 3/4"-6" solitary or paired, spike-like, terminal clusters 1/3"-3/4" thick on a stalk jointed at the top; blooms June-Sept.
Fruits: shiny, dark, dry seed
Habitat: wet; meadows, shallows, water < 7' deep; in sediment soil
Conservation Status: Native