Rhizome

Overview

A rhizome is a modified subterranean plant stem that sends out roots and shoots from its nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from axillary buds and grow horizontally. The rhizome also retains the ability to allow new shoots to grow upwards.

Morphology

A rhizome is the main stem of the plant. A rhizome has nodes and internodes. The nodes hold one or more leaves, as well as buds which can grow into new shoots or rhizomes. The internodes or segments between nodes are more or less elongated, with different lengths in different plants.

A close-up view of a rhizome, showing the nodes and internodes.

Function

Rhizomes store starches and proteins and enable plants to survive underground during unfavorable seasons. These specialized stems allow a parent plant to propagate vegetatively (asexually), producing clones, and are often involved in allowing plants to spread over a wide area, even when conditions are not conducive to the survival of offspring or seedlings.

Types of Rhizomes

There are two types of rhizomes: sympodial and monopodial. Sympodial rhizomes grow laterally, producing a series of shortened vertical shoots that grow into new plants. Monopodial, or Turioniferous rhizomes, on the other hand, produce long lateral shoots that can grow quite far from the mother plant.

Examples of Plants with Rhizomes

Many plants have rhizomes, including certain species of ferns, bamboos, and orchids. Some species of iris, ginger, lily, canna, and turmeric also have rhizomes. Invasive plants such as Japanese knotweed and giant reed also have rhizomes that allow them to spread rapidly and dominate a landscape.

Economic Importance

Rhizomes are used in propagation of many ornamental and crop plants. They also have economic importance in the production of certain spices, medicinal plants and other useful products. For example, ginger and turmeric are commercially valuable plants that are propagated through rhizomes.

Environmental Impact

Rhizomes can contribute to the spread of invasive plant species. These plants can quickly dominate an ecosystem, displacing native species and altering habitats. They are often difficult to control due to the ability of the rhizome to grow new shoots, even from small pieces.