Dotted Duckweed - Landoltia punctata

"Spirodela punctata" is a species of duckweed. The species is morphologically intermediate between "Lemna" and other species of "Spirodela". In 1999 D.H. Les and D.J. Crawford proposed segregating the species to a new genus "Landoltia" containing just the species "L. punctata", on the basis of biochemical and DNA studies.