Duckweed (Lemna minor)
Watermeal (Wolffia columbiana)
Duckweed and Watermeal are the smallest of the flowering plants. They float on the surface of the water. Duckweed is about the size of oatmeal flakes, and is usually a light green color. It has tiny rootlets hanging down in the water. Watermeal has neither leaves or rootlets, and appears as minute green grains floating on the water. These plants often occur together. Frequently the growth of duckweed and watermeal can be so dense as to completely cover the pond surface. Both of these plants, but especially watermeal, can be extremely difficult to control.