Glyceria is known commonly as mannagrass in the United States, or, in the UK, sweet-grass. These are perennial rhizomatous grasses found in wet areas in temperate regions worldwide. The base of the grass grows along the ground and may root at several places. Then it grows erect and bears leaf blades which may be flat or folded. The panicle inflorescences nod when heavy. Some mannagrasses are considered weeds while others are endangered in their native habitats.