A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water.[1] Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form classification system.[2][3] Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions (such as cold, excessive heat, lack of light or drought).