Amaranths are dicotyledonous plants that belong to the Amaranthaceae family which comprises more than 50 genera, distributed in tropical and subtropical zones of the world (Kigel and Rubin 1985). Most of these genera are native to America, and they grow in disturbed areas and produce large seedheads with small seeds. Some of them, like Amaranthus spinosus L. and A. powellii S. Watts. are considered to be weeds, while others like A. hypochondriacus L., A. cruentus L., A. retrofiexus L. and A. caudatus L. are consumed as a grain and A. dubis Mart and A. dubis L. are used as fresh vegetables when young. Additionally, some other species are used as ornamentals because of the bright colors of their leaves and inflorescences (Kiegel and Rubin 1985).