Cladium mariscus
 Cladium mariscus is a species of flowering plant in the sedge family known by the common name saw-sedge or sawtooth sedge. Previously it was known as elk sedge. It is native of temperate Europe and Asia where it grows in base-rich boggy areas and lakesides. It can be up to 2.5 metres (8 ft 2 in) tall and has leaves with hard serrated edges.