During these periods, parts of the plant die and then when conditions become favourable again, re-growth occurs from buds in the perennating organs.
For example, geophytes growing in woodland under deciduous trees (e.g. bluebells, trilliums) die back to underground storage organs during summer when tree leaf cover restricts light and water is less available.
Many succulents have leaves adapted for water storage, which they retain in adverse conditions.
In common parlance, underground storage organs may be generically called roots, tubers, or bulbs, but to the botanist there is more specific technical nomenclature: Some of the above, particularly pseudobulbs and caudices, may occur wholly or partially above ground.
Succulents are plants which are adapted to withstand periods of drought by their ability to store moisture in specialized storage organs.