A very primitive plant looking like a miniature shrub of thin twigs. It is used as a diuretic, astringent, and used to treat kidney stones, urinary tract infections and brittle nails. High in silica, potassium and calcium. Known as Pewterwort because it was used to polish metals, especially pewter, in the past. Both horsetails can be spread aggressively where happy. Prefers damp ground.