Fanwort is a submersed, floating plant with short rhizomes. The shoots are grass green to olive green or sometimes reddish brown. The leaves are either submersed or floating; submersed leaves are finely divided and arranged in opposite pairs on the stem. Floating leaves are small and inconspicuous. The floating leaves are less than 1/2 inch long and 1/3 inch wide. The leaf blade attaches to the center. The flowers are white and small and float on the water surface.