The potato is a perennial plant of the Solanaceae, or nightshade, family, grown for its starchy tuber. In recent centuries potatoes have become the world's most important tuber crop and its fourth most important source of food energy (after rice, wheat, and maize): farmers and gardeners grow them worldwide. Growers cultivate thousands of different varieties of potato. The potato originated in the Andes, in the area of present-day countries such as Peru, Ecuador, Colombia, and Venezuela. Pre-Columbian inhabitants of the Andean cultures cultivated around 200 different kinds of potatoes.