Amaranth plants are classified as pseudocereals that are grown for their edible starchy seeds, but they are not in the same botanical family as true cereals. There are about 75 species in the genus Amaranthus. The Aztecs cultivated amaranth as a staple grain crop. Amaranth grain is high in protein and lysine (an amino acid found in low quantities in other grains), deficient in essential amino acids such as leucine and threonine (both of which are present in wheat germ), but free of gluten, which makes it a viable grain for people with gluten intolerance.