rhizomen

Rhizomen are horizontal underground stems that grow beneath the soil surface. They differ from roots because they are stems with nodes and internodes, capable of producing new shoots above ground and roots below ground at each node. They often store carbohydrates, supporting perennial growth and vegetative propagation across seasons. The growth habit allows plants to colonize new space by extending the rhizome horizontally, while new shoots arise from nodes and the rhizome itself continues to elongate.

In structure, rhizomen can be fleshy or fibrous and may bear scale-like leaves. They occur in many plant groups, including grasses, flowering plants, and some ferns. They are ecologically important because they enable rapid spreading and resprouting after disturbance such as mowing or fire, and they serve as reservoirs of nutrients during adverse conditions.

Examples include culinary ginger (Zingiber officinale) and turmeric (Curcuma longa), as well as ornamental species such as iris and canna, and woody grasses like bamboo. Grasses such as quackgrass (Elymus repens) commonly rely on rhizomen to propagate. Ferns often have underground rhizomes that bear roots along their length.

Rhizomen are distinct from tubers, bulbs, and stolons. Tubers are swollen ends of stolons or roots that store starch; bulbs are underground shoots surrounded by leaf bases. In horticulture, rhizomen can be divided and replanted to propagate plants, though aggressive rhizomatous species may require management to limit spread. Note that rhizomen is the Dutch plural form of rhizoom; in English the plural is rhizomes.