Stolon

Lore & Background

In botany, stolons are plant stems that grow at the soil surface or just below ground, forming adventitious roots at the nodes and new plants from the buds. They are often called runners. Rhizomes, in contrast, are root-like stems that may grow horizontally at the soil surface or in other orientations underground; not all horizontal stems are called stolons. Plants with stolons are called stoloniferous. A stolon is a plant propagation strategy, and the complex of individuals formed by a mother plant and all its clones produced from stolons form a single genetic individual, a genet. Stolons may have long or short internodes. The leaves along the stolon are usually very small, but in a few cases such as Stachys sylvatica are normal in size. Stolons arise from the base of the plant. In strawberries the base is above the soil surface; in many bulb-forming species and plants with rhizomes, the stolons remain underground and form shoots that rise to the surface at the ends or from the nodes. Typically after the formation of the new plant the stolon dies away in a year or two, while rhizomes persist normally for many years or for the life of the plant. The horizontal growth of stolons results from the interplay of different hormones produced at the growing point and hormones from the main plant, with some studies showing that stolon and rhizome growth are affected by the amount of shady light the plant receives. In mycology, a stolon is defined as an occasionally septate hypha that connects sporangiophores together. Root-like structures called rhizoids may appear on the stolon as well, anchoring the hyphae to the substrate. The stolon is commonly found in bread molds, seen as horizontally expanding across the mold. In zoology, some bryozoans form colonies through the connection of individual units by stolons. Some colonial Cnidaria develop as stolons with interconnected medusoid structures that later separate. Some worm-like animals, such as certain Polychaeta in the genus Myrianida, form stolons containing eggs or sperm which trail behind the main body before detaching to mate with other stolons.

Reader's Guide

Stolons are significant in biology as a means of asexual reproduction and colony formation across multiple kingdoms. In botany, stolons allow plants like strawberries and grasses to spread vegetatively, creating genetically identical clones that form a single genet. This strategy is important for plant propagation, both in natural ecosystems and in agriculture, where stoloniferous plants can be used for ground cover or turf. The distinction between stolons and rhizomes is morphologically and functionally important: stolons typically have longer internodes, function in seeking light and propagation, and often die after a few years, while rhizomes persist and store carbohydrates. In mycology, stolons facilitate the spread of molds such as bread mold by connecting sporangiophores. In zoology, stolons enable colonial organisms like bryozoans and cnidarians to form interconnected colonies, and in some polychaete worms, stolons serve as reproductive units that detach and mate. The concept of stolons also extends to paleontology, where stolon-based reproduction is thought to have been used by Rangeomorphs in the Ediacaran period. Understanding stolons helps clarify how organisms expand, reproduce, and maintain genetic continuity across diverse taxa.

Did You Know?

• In potatoes, stolons start to grow within 10 days of plants emerging above ground, with tubers usually beginning to form on the end of the stolons.
• Some worm-like animals, such as certain Polychaeta in the genus Myrianida, form stolons containing eggs or sperm which trail behind the main body before detaching to mate with other stolons.
• Stolon-based reproduction is thought to have been used by Rangeomorphs in the Ediacaran period.
• In mycology, a stolon is defined as an occasionally septate hypha that connects sporangiophores together.

Botanical Architecture and Hormonal Orchestration

A stolon in botany is a horizontal stem that emerges from the base of a plant and travels along or just beneath the soil surface. Its internodes can be long or short, and the leaves it bears are typically very small, though exceptions like Stachys sylvatica carry normal-sized foliage. At each node, adventitious roots develop—often encircling the node entirely—and the hormones those roots release trigger the stolon to initiate new shoots bearing full leaves. The direction and pace of this horizontal growth are governed by a complex interplay between hormones produced at the stolon's own growing tip and signals sent from the parent plant. Research has shown that light conditions play a significant role: plants receiving a mix of shade and sunlight tend to produce more stolons and greater branching, whereas those in full sun or full shade generate fewer. In strawberries, the stolon originates above ground, while in many bulb-forming and rhizomatous species it stays underground, sending shoots upward from its nodes or terminal ends. Typically, once a new plant has established itself, the stolon that produced it dies off within a year or two.

The Stolon–Rhizome Distinction

Although both stolons and rhizomes are horizontal stems, they differ in structure, function, and longevity in ways that matter to botanists. Holm drew a formal boundary: a rhizome is a horizontal, usually subterranean stem that produces roots from its lower surface and green leaves from its apex, developing directly from the embryo's plumule. A stolon, by his definition, is an axillary, subterranean branch that bears only membranaceous, scale-like leaves rather than true green foliage. Functionally, stolons serve primarily as propagation organs, seeking out light and generating new genetic clones, while rhizomes act as carbohydrate storage organs and maintain meristem tissue to keep the parent plant alive across seasons. This difference in purpose is reflected in lifespan: a stolon generally dies within a year or two after producing a new plant, whereas a rhizome persists for many years or the plant's entire life, adding length at its growing ends each season. Some species blur the line—Lily-of-the-valley and certain Asters possess stoloniferous rhizomes, long thin structures with indeterminate growth and mostly dormant lateral buds. Several Iris species, including Iris stolonifera, attach true stolons directly to their rhizomes.

Beyond the Plant Kingdom

The word stolon reaches far beyond botany. In mycology, it describes an occasionally septate hypha that links sporangiophores together, often with root-like rhizoids anchoring the structure to the substrate. These horizontal connections are a hallmark of bread molds, visible as the mold expands laterally across its surface. In zoology, the concept appears in colonial organisms: certain bryozoans build colonies by connecting individual units through stolon-like bridges, and some colonial Cnidaria develop as stolon networks of interconnected medusoid structures that later separate into independent individuals. The most striking example comes from the polychaete worm Megasyllis nipponica, which produces stolons bearing their own eyes, antennae, gut, and brain. These self-contained structures trail behind the parent body, detach, seek out a stolon of the opposite sex, and mate to produce fertilized eggs. Even in the deep past, stolon-based reproduction is thought to have been employed by Rangeomorphs during the Ediacaran period, suggesting this horizontal-connective strategy is ancient. In animal contexts, stolons are typically exoskeletal structures.

Propagation, Persistence, and Practical Impact

Stoloniferous growth is one of nature's most effective cloning strategies. The mother plant and every clone it produces through its stolons together constitute a single genetic individual, known as a genet. In potatoes, stolons begin growing within ten days of the plant emerging above ground, and the tubers that form at their tips are essentially modified stolons storing food reserves with a few buds that will grow into new stems. Because a potato tuber is not a rhizome, it does not generate roots itself; rather, the new stem that reaches the surface produces them. In aquatic habitats, Hydrilla uses stolon-borne tubers both to spread and to survive dry periods. Some Cyperus species terminate their stolons in tubers that become new plants. In agriculture, Convolvulus arvensis is a persistent weed that spreads via underground stolons producing rhizomes, making it difficult to eradicate. Grasses such as Zoysia japonica and Cynodon rely on soil-level stolons that root at the internodes. Plants with long, slender stolons are termed sarmentose. Notably, many flowering plants produce no stolons at all, and the trait is absent in some bulbous species despite their underground architecture.