Persicaria pensylvanica (L.) M.Gómez
Family: Polygonaceae
Pennsylvania knotweed, Pennsylvania smartweed, pinkweed
Persicaria pensylvanica image
Botanical Illustration  
Etymology: Persicaria: peach-like, the medieval name for knotweed
Plants: erect, annual, 2'-5' tall forb; stems with nodes either smooth or cut, but not hairy; taprooted
Leaves: alternate, variable but usually lance-like, often woolly beneath
Flowers: white-green to pink, 4- or 5-parted, 1/8" long, petals and petal-like sepals connected at the base; inflorescence many 1/3"-2" long, nodding, spike-like clusters on a stalk jointed at the top; blooms July-Sept.,
Fruits: dry seed flat or concave on both sides
Habitat: wet to moist; disturbed sites