Eriophorum (cottongrass, cotton-grass or cottonsedge) is a genus of flowering plants in the family Cyperaceae, the sedge family. They are found throughout the arctic, subarctic and temperate portions of the Northern Hemisphere in acid bog habitats, being particularly abundant in Arctic tundra regions.They are herbaceous perennial plants with slender, grass-like leaves. The seed heads are covered in a fluffy mass of cotton which are carried on the wind to aid dispersal.