Sedges are the grasses of the wet places, the sharp-edged plants that cut your fingers when you pull too hard. They are the architects of the swamp, the ones that hold the riverbank together. And there was once a sedge that grew taller than any alive today – a sedge with leaves that rose 2.5 metres from the water, with seed heads as big as a man's fist, with roots that spread through the mud like a net. It was the giant sedge, the wetland phantom, and it is gone. Height and engineering made it special. A 2.5-metre sedge is a giant. Its leaves were tall and sharp-edged, forming dense stands that lined the riverbanks and filled the swamps. Its root system was massive, spreading through the mud, holding the soil together, preventing erosion. It was the engineer of the wetland, the plant that made the swamp a swamp. It built the wetland. The giant sedge was a foundation species. Its dense stands trapped sediment, building up the swamp floor. Its roots held the riverbank together, preventing the channel from widening. Its leaves provided shelter for birds, insects, and fish. It was the heart of the swamp community. Sedges reproduce by seeds, produced in dense, spiky seed heads. The giant sedge produced massive seed heads, each containing hundreds of seeds. The seeds were dispersed by water and by birds, carried to new wetlands. That strategy works when the swamps are vast and the water is clean. It fails when the swamps are drained and the rivers are straightened. Swamp drainage and river straightening destroyed it. When Europeans arrived, they drained the lowland swamps for pasture. They straightened the rivers for flood control. The giant sedge, which needed permanent water and undisturbed riverbanks, could not survive. Its stands were drained, ploughed, and planted with grass. At the same time, introduced grazing animals – cattle, sheep, horses – ate the tender young shoots and trampled the root systems. The giant sedge could not compete. By the 1900s, it was gone. The last stands were probably drained by a farmer or eaten by a cow. No one knew they were the last. The smaller sedges survived. They are shorter, more adaptable, able to grow in a wider range of conditions. They are the survivors, the ones that kept their heads down. But the giant sedge is extinct. A few pressed specimens in a herbarium, a few seeds in a core sample, and the memory of a sedge that used to tower over the swamps, a wetland phantom on the riverbank. The wetland phantom has faded. The swamps are not as deep as they used to be.