Carex nigraCarex nigra is a perennial species of plant in the sedge family Cyperaceae. Common names include: smooth black sedge, 'black sedge and common sedge'.DescriptionCarex nigra is a tussock-forming, evergreen perennial sedge, reaching up to 70cm in height. Leaves are bluish-green in colour. Flower spikes and seed heads are purplish-black, appearing in early to late summer.Distribution and habitatIt is native to wetlands of Europe, western Asia, north Africa, and eastern North America. The eastern limit of its range reaches central Siberia, Turkey and the Caucasus. It favours marshes, wetlands and alkaline fens.