Any of several plant species of the genus Maranta (family Marantaceae), whose rhizome s yield an edible starch.
Chief among these is the herbaceous perennial M. arundinacea , the source of genuine, or West Indies, arrowroot. The powder obtained from the harvested roots is almost pure starch; it is used in cookery as a thickener. Arrowroot is easily digested and is used in diets requiring bland, low-salt, and low-protein foods. Its name is sometimes applied to starches obtained from other plants and used as substitutes for true arrowroot. Brazilian arrowroot, from the cassava plant, is the source of tapioca.