Quisetum Arvense, sometimes called Shavegrass or Scouring rush for its ability to polish metal, is an ancient plant in the Equisetaceae family that once covered the earth more densely than forests over 350 million years ago. It is named for the shape of its foliage that somewhat resembles that of a horseโ€™s tail. although itโ€™s just a couple of feet in height, it was once as tall as a palm tree.