Pistia stratiotes

The water lettuce is one of the few aquatics and cosmopolitan species of the arum family. It is broadly spread in tropical and subtropical countries in lakes, rivers, and lagoons. In the Guarani pharmacology, the leaves are used as a source of vitamin C. The species has been used for treating the quality of water, as well as for phytoremediation of aquatic environments polluted by heavy metals, for it is able to tolerate and accumulate them. The leaves are furry and thick.