The sweet potato is a dicotyledonous plant that belongs to the bindweed or morning glory family, Convolvulaceae. Its large, starchy, sweet-tasting, tuberous roots are a root vegetable. The young leaves and shoots are sometimes eaten as greens. The sweet potato is commonly thought to be a type of potato but does not belong to the nightshade family, Solanaceae, but both families belong to the same taxonomic order, the Solanales. The sweet potato, especially the orange variety, is often called a "yam" in parts of North America, but is botanically very distinct from true yams.