The lemon, is a species of small evergreen tree in the flowering plant family Rutaceae, native to South Asia, primarily North eastern India.The tree's ellipsoidal yellow fruit is used for culinary and non-culinary purposes throughout the world, primarily for its juice, which has both culinary and cleaning uses. The pulp and zest are also used in cooking and baking. The distinctive sour taste of lemon juice makes it a key ingredient in drinks and foods such as lemonade and lemon meringue pie.