Knotweed.Polygonum Pennsylvanicum.
Found in barrens and waste places in August and September.
Branching much and sprawling in manner, this plant grows from 1 to 3 feet in height; it is jointed, noticeably shining, and smooth except for the new growths and flower-stems which are rough with hairs. Its color is green, somewhat red at the joints, which are covered loosely by sheaths of a coarse weak fabric.
The leaf is long-pointed at each end, and roughened by hairs on the ribs, edges, and upper surface; the texture is flimsy, and the color a crude green. The arrangement is alternate.
The small and inconspicuous flowers are 5-parted, and vary from pink to green-white in color; they are tightly and irregularly bunched in a terminal club-shaped spike, with a little leaf at its base—frequently a second bunch of flowers occurs a little lower down the stem.
Found commonly in great masses the plant serves to hide the ugly remnants man casts into the fields it chooses for its habitation.