An ancestor of stone fruits such as nectarines, peaches, plums and cherries, the almond is one of the world’s oldest cultivated foods. The almond tree is similar to that of a peach in size and shape, and even the tough gray-green fruit that encloses the almond kernel resembles that of its sweeter, fleshier cousin. Today, almost all of the almonds grown in the United States are grown in California.