Carex litorosa or sea sedge is endemic to the North, South and Stewart Islands.
It is found coastally in salty, brackish marshes and on sandy, tidal river banks. An upright sedge to 800 mm tall (but usually smaller), that forms pale green or reddish, dense tussocks with curly tops. Leaves are flat on one side, curved on the other and slightly serrated along the edge, 1.5 mm wide and about the same length as the flower stem. It flowers from October to December with seed heads developing from December to April (but seedheads long persistent). Carex litorosa is in serious decline and in some areas it has almost disappeared due to habitat loss through coastal development. Encroachment by weeds is a serious problem in the North Island, especially from species such as spartina, tall fescue and Carex divisa. In Christchurch it is found around the estuarine areas and is in serious decline almost to the point of being lost, especially after damage to areas due to the earthquakes, that it has been growing.