PENNSYLVANIA SMARTWEED, Polygonum
pensylvanicum L. 1, lower part of plant; 2, upper part
of plant; 3, section of stem, leaf, and leaf sheath; 4, flower;
5, seed. Annual, reproducing by seeds. Stems smooth,
swollen at nodes, branching, 1 to 4 feet (0.3 to 1.2 m) tall. Leaves
smooth, pointed, alternate, 2 to 6 inches (5 to 15 cm) long, with a sheath
at the base extending around the stem. Flowers bright pink or rose,
5-parted, arranged in a short spike. Seeds shiny, black, smooth,
flattened, almost circular. Found in cultivated ground and waste
places, and along ditches.
LADYSTHUMB, Polygonum persicaria L. 6, upper
part of plant; 7, section of stem, leaf, and leaf sheath; 8,
seed. Annual, reproducing by seeds. Stems smooth, sometimes
hairy, much-branched, 6 inches to 3 feet (15 to 90 cm) tall. Leaves
alternate, pointed at both ends, 1 to 6 inches (2.5 to 15 cm) long, with
smooth edges and usually a dark spot in the middle. Sheath at base
of the leaf fringed with short bristles. Flowers pink or purplish.
Seeds almost circular, flattened or 3-sided, smooth, black, shiny.
Found in same areas as above.