This is a well-known weed, growing with pertinacity in cultivated grounds, with a strong root. The farmers consider the dockweed among their most unwelcome growths. Leaves, narrow, with wavy margins. Flowers crowded in whorls, in long panicles.

Swamp Dock R. verticillktus. - A tall species found in swamps, with flowers whorlcd about the stem in loose, almost leafless racemes. Often the lower leaves of many of these species turn a bright red early in the season.

Bitter Dock R. obtusifolius has flowers whorled in looser, more distant panicles. Lower leaves ovate, heart-shaped, obtuse, the upper narrower, acute. Calyx wings spiny-toothed; achenes smooth, red.