High Quality Content by WIKIPEDIA articles! Glyceria fluitans (L.) R. Br. (syn. Festuca fluitans L.; Poa fluitans (L.) Scop.; Panicularia fluitans (L.) Kuntze; Water Mannagrass) is a species of perennial grasses in the genus Glyceria native to Europe, the Mediterranean region and Western Asia and occurring in wet areas such as ditches, riverbanks and ponds. It is also known as Floating Sweet Grass.