Its inflorescence is small and often interpreted as one flower. It consists of only 3 to 9 male flowers and one single, highly reduced female one. Due to their habitat and to their reduced habit, they were often understood as a link between Araceae and Lemnaceae. Geography Pistia occurs all around the globe in tropical and subtropical zones. Sporadically, it can escape from cultivation in temperate regions.
Far distribution makes the geographical origin of the genus uncertain.
Fossil record and wide distribution imply an ancient origin and an early distribution. Probably, clones from geographically different origins differ morphologically. Therefore, Pistia is treated as a monotypic genus and no subspecies are established, so far. In the mature seed, the plumule and cotyledon are preformed. It unfolds the thin, non-hairy cotyledon which enables it to float in the cohesion field of the water surface, after the plantlet has risen to air contact.