Small duckweeds are floating plants. They are commonly found in still or sluggish waters. They often form large floating mats. There are three types of Lemna occurring in Florida (Wunderlin, 2003). Small duckweed is located throughout the US; and in PR (Kartesz, 1999).
Small duckweeds are tiny (1/16 to 1/8 inch) green plants with shoe-shaped leaves. Each plant has two to several leaves joined at the base. A single root hangs beneath.
Small duckweed may be confused with giant duckweed, Spirodela polyrhiza. Compare the leaf size and root number.
For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.