Pecans are the soft, fatty seeds of a very large tree, a distant relative of the walnut that is native to the Mississippi and other river valleys of central North America, and found as far south as Oaxaca. Carya illinoiensis is one of about 14 species of hickories, and its nuts among the tastiest and easiest to shell. Wild pecans were enjoyed by the native Americans, and apparently made into a kind of milk that was used for drinking, cooking, and possibly fermenting. The earliest intentional plantings may have been made by the Spanish around 1700 in Mexico, and a few decades later the trees were grown in the eastern British colonies. The first improved varieties were made possible in the 1840s by a Louisiana slave named Antoine, who worked out how to graft wood from superior trees onto seedling stocks. Georgia, Texas, and New Mexico are now the largest producers of pecans.