Plants of the swamp are the wet ones, the soggy ones, the ones that grow where no one wants to walk. But without them, there would be no wetlands – no bogs, no swamps, no peat. They are the engineers of the soggy world. And there was once a plant that grew taller than any alive today – a plant that looked like a moss but stood like a grass, its stems rising 40 centimetres from the black water, its leaves holding water like a living sponge. It was the giant swamp mossgrass, and it is gone. Height and water-holding capacity made it special. A 40-centimetre wetland plant is a giant – a dense stand of upright stems, packed together so tightly that the water beneath was hidden. It was a living sponge, holding hundreds of times its weight in water, keeping the wetland wet even in drought. It built the bog. In a healthy wetland, the plants are the engineers – their roots stabilise the peat, their leaves shade the water, their decaying matter adds to the accumulating organic layer. The giant swamp mossgrass was the dominant plant of these wetlands, the one that turned open water into solid ground. Its dense mats provided habitat for fish, eels, and insects. Its leaves held moisture through dry spells, releasing it slowly back into the wetland. It was the heart of the swamp. It reproduced by spores, like mosses, and by fragmentation. It grew slowly, adding a few centimetres each year. A 40-centimetre plant might be decades old. That strategy works when the swamp is vast and the water is clean. It fails when the swamp is drained and the fires come. Swamp drainage and fire destroyed it. When Europeans arrived, they drained the great lowland swamps for farming. They dug ditches, laid pipes, burned the peat. The giant swamp mossgrass, which needed permanent waterlogging to survive, could not grow on dry land. Its stems wilted. Its leaves dried out. Its spores could not germinate. At the same time, introduced grazing animals – cattle, sheep, horses – trampled the remaining wetlands. They ate the tender stems, churned the water into mud, destroyed the delicate mats. It could not compete. By the 1910s, it was gone. The last patches were probably drained or dug up by a farmer who had no idea what he was destroying. He drained the bog, planted grass, and the floor ghost disappeared. The smaller wetland plants survived. They are more adaptable, able to grow in smaller bogs, wet gullies, and regenerating wetlands. They are the survivors, the low-growing ones, the plants that kept their heads down. But the giant swamp mossgrass is extinct. A few pressed specimens in a herbarium, a few spores in a core sample, and the memory of a plant that used to carpet the wetlands, 40 centimetres tall, dense and green. The floor ghost has faded. The swamp is not as wet as it used to be.