One familiar example of a rhizome is ginger. Culinary ginger root is a rhizome, a kind of stem that grows underground, parallel to the surface, which stores food to renew growth in times of hardship. Rhizomes can grow roots and shoots to ensure the survival of new growth.
Rhizomes are specialized stems, similar to corms and tubers. All three structures are underground stem growths that plants use, in part, to store food. When a plant's above-ground organs die off due to cold weather, drought or other adverse conditions, it can grow back thanks to the underground food stores and root systems maintained by the corm, tuber or rhizome.
Unlike tubers and corms, however, rhizomes grow horizontally close to the surface of the ground. This creeping growth habit allows the plant to spread, rather than growing back in a potentially unfavorable location. Other rhizomes in culinary use include tumeric and fingerroot.