Lemna - Genus of flowering plants in the family Araceae

"Lemna is a genus of free-floating aquatic plants referred to by the common name "duckweeds." They are morphologically divergent members of the arum family Araceae. These rapidly growing plants have found uses as a model system for studies in community ecology, basic plant biology, ecotoxicology, and production of biopharmaceuticals, and as a source of animal feeds for agriculture and aquaculture. Currently, 14 species of Lemna are recognised. - Wikipedia"