A rhizome is a modified subterranean stem of a plant. It often sends out roots and shoots. Rhizomes form from axillary buds and are grow perpendicular to gravity. A piece of rhizome can give rise to a new plant. The rhizome can store starches, proteins, and other nutrients for the plant. These nutrients are useful when the plant sends new shoots out after winter. The plant hormones ethylene and jasmonic acid are used to help induce and regulate rhizome growth.