Floating Sweet-grass

Glyceria fluitans (syns Festuca fluitans, Poa fluitans, Panicularia fluitans), known as Floating Sweet-grass  and water mannagrass, is a species of perennialgrass 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 has a creeping rootstock, a thick stem which rises to one metre. The leaves are long, narrow and pale green, rough on both sides, often folded at the keel which lies on the surface of the water.

Glyceria fluitans is a component of Purple moor grass and rush pastures, a type of Biodiversity Action Plan habitat in the UK. This habitat occurs on poorly drained neutral and acidic soils of the lowlands and upland fringe. It is found in the South West of England, especially in Devon.