Duckweed is often confused with algae. From afar, they both appear as a green slimy film on a water’s surface. However, each duckweed is an individual plant, they are the smallest flowering plants known and their roots aren’t interconnected. Known as duckweeds, water lentils, or water lenses, Lemnoideae is a subfamily of flowering aquatic plants that float on or just beneath the surface of still or slow-moving bodies of fresh water and wetlands. These plants have a simple structure, only a few cells thick, often with air pockets that allow it to float on or just under the water surface. Depending on the species, each plant may have no root or may have one or more simple rootlets. Duckweeds tend to be associated with fertile, even eutrophic conditions. Duckweeds can double their mass in between 16 hours to 2 days under optimal nutrient availability, sunlight, and water temperature. This is faster than almost any other higher plant. It's is an important food source for waterfowl.