Cladium (fen-sedge, sawgrass or twig-sedge) is a genus of large sedges, with a nearly worldwide distribution in tropical and temperate regions.

These are plants characterized by long, narrow (grass-like) leaves having sharp, often serrated (sawtooth-like) margins, and flowering stems 1–3 m tall bearing a much-branched inflorescence.

One typical and well-known area of extensive saw-grass growth is the Florida Everglades;[3] sawgrass is the plant referred to by the descriptor, "River of Grass".

[6] Phosphorus from agricultural runoff favoured dense cattail over rich sawgrass habitats, choking off water access for animals and birds.

Several fossil endocarps of †Cladium bicorne and †Cladium reidiorum have been described from middle Miocene strata of the Fasterholt area near Silkeborg in Central Jutland, Denmark.