Tubers are a type of enlarged structure used as storage organs for nutrients in some plants, derived from stems or roots. Tubers help plants perennate, provide energy and nutrients, and are a means of asexual reproduction.

A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. 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. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions.