The Lemnaceae, commonly known as duckweeds, are the smallest, fastest-growing, and simplest of flowering plants. In this globally distributed aquatic monocot family, there are 33 species representing five genera: Spirodela, Landoltia, Lemna, Wolffiella, and Wolffia. The individual plants range in size from 1.5 cm long (Spirodela polyrhiza) to less than one millimeter (Wolffia globosa). Therefore, there is a successive reduction of morphological structures in parallel with evolutionary advancement within the family. Duckweeds are not simply miniature versions of larger angiosperms; they represent a highly modified structural organization that resulted from the alteration, simplification, or loss of many morphological and anatomical features. The biomass doubling time of the fastest-growing duckweeds in optimal growth conditions is less than 30 hours, nearly twice as fast as other “fast” growing flowering plants and more than double that of conventional crops.