First record of Pistia stratiotes (water lettuce) from Gilan province (North of Iran).
In order to study the conservation status of the plant species and ecosystems of Gilan province (North of Iran), an alien species was observed in some ponds in the east of Rasht, which covered the surface of ponds. The plant samples were collected and photographed; also the relevant environmental data were recorded in situ. The collected specimens were studied with various scientific resources and led to the identification of the species as Pistia stratiotes which is commonly known as "water lettuce". This species is recorded for the first time from Iran. The plant is pan-tropical and is considered to be one of the most widely distributed aquatic invasive plants in the world. The paper presents data on taxonomic remarks of this plant along with some notes on its geographical distribution and habitat. This report also highlights the need for implementing early control measures with special emphasis on all freshwater habitats in the northern parts of the country.