High Quality Content by WIKIPEDIA articles! Eriophorum vaginatum L. (Hare`s-tail Cottongrass, Tussock Cottongrass, Sheathed Cottonsedge) is a species of perennial herbaceous plants in the family Cyperaceae, native to bogs and other acidic wetlands throughout the Holarctic Kingdom. It is a 30-60 cm high tussock-forming plant with erect solitary spikelets.