Hare's-Tail Rush, or Single-Headed Cotton-GrAss, Eriophorum raghiatum, L. a perennial plant, found in marshy heaths, on bogs and moors; principally in the northern counties of Britain. - The whole plant, previously to its flowering in June, is eaten with great avidity by sheep : and it is asserted by shepherds, that these animals will, after being reduced by hunger, recover more speedily, and thrive much better on the hare's-tail rush, than on turnips. In a ripe state, however, it is chiefly used for rush-lights : the wool, or down growing on this plant, though short and brittle, may be applied to similar purposes witb those of the Cotton-grass.