Rhizome

In botany and dendrology, a rhizome (/ˈraɪzoʊm/, from Ancient Greek: rhízōma "mass of roots", from rhizóō "cause to strike root") is a modified subterranean stem of a plant that is usually found underground, often sending out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks and rootstocks. Rhizomes develop from axillary buds and are diageotropic or grow perpendicular to the force of gravity. The rhizome also retains the ability to allow new shoots to grow upwards.

If a rhizome is separated into pieces, each piece may be able to give rise to a new plant. The plant uses the rhizome to store starches, proteins, and other nutrients. These nutrients become useful for the plant when new shoots must be formed or when the plant dies back for the winter. This is a process known as vegetative reproduction and is used by farmers and gardeners to propagate certain plants. This also allows for lateral spread of grasses like bamboo and bunch grasses. Examples of plants that are propagated this way include hops, asparagus, ginger, irises, Lily of the Valley, Cannas, and sympodial orchids. Some rhizomes which are used directly in cooking include ginger, turmeric, galangal, and fingerroot.