Common duckweed

This small aquatic herbaceous plant, with a diameter of less than 0.5 cm, forms colonies floating on the surface of calm waters. The common duckweed (Lemna minor) is characterized by the absence of any clear distinction between the stem and the leaves.

The green parts, or thalli, are very tiny (2 x 3 mm) and round or oval. They grow in groups of 3 or 4. Their upper surface is lime green and their under surface is a paler green.

At the base of each thallus is a single 2.5 to 10 cm-long floating root.