Duckweed is the smallest flowering plant and lives only in aquatic environments. It is known for its ability to spread rapidly over the surface of water bodies. It is often considered a pest or weed. However, it is also used in environmental remediation because it takes up excess nitrogen and phosphorous from the water. It can be used for animal feed and is eaten by humans in some regions.

Like all plants, duckweed has the capacity for indeterminate growth, meaning that it continues to grow throughout the life of the plant. Meristematic tissue makes this possible. This tissue is made up of embryonic cells, which are constantly dividing to create additional cells. Some of the cells differentiate and become other types of tissue, while others stay in the meristem region and continue dividing. This gives plants a constant source of new cells to build tissue and organs.

Duckweed reproduces asexually, cloning itself repeatedly. As each frond matures, it begins producing new buds in the meristematic zone near the center of the frond. These buds grow into new fronds while still attached to the parent frond. When they mature, they break off. At this point, they have likely already begun producing fronds of their own. This cycle of reproduction allows duckweed to have a very fast rate of growth. It is capable of doubling in biomass over the course of 16 hours. Although duckweed does produce flowers, they are not required for reproduction.