Types of stem

There are different types of stems in nature.

The stem is the main support axis of the plant, and some types of stems have adaptations and, like the roots, are classified according to their shape and function. Below we can see a scheme of how the classification of stems occurs.

The aerial stems grow perpendicular to the ground

Creeping stems are long, thin structures that grow above the ground. They are classified in sarmento and stolons (also called stolon) The creeping twig-like stem is characterized by having only one root attachment point, and may be full of branches or modified leaves called tendrils. This type of stem can climb on supports. The stolon is a type of stem that grows parallel to the ground, forming buds from space to space, and can give rise to new plants with roots and leaves. This is the type of stem that occurs in strawberry and grass.

The stems called climbers or volubles are thin and long structures that grow coiled in the most varied types of support, such as chayote, jasmine and ivy.

Stems classified as erect are those that grow perpendicular to the ground.

Trunks are a type of aerial stem. They have robust and cylindrical structures, developed at the bottom with ramifications at the top. They can be found in basal dicots, in most trees and shrubs of the gymnosperms group.

 Typical of vegetables such as cabbage, the stem is a soft structure, usually green and branched.

The stipes are usually unbranched stems, which have a cluster of leaves in their upper part. It is a type of stem found in species of palm trees.

The culm-like stem is very similar to the stipe: they differ only because they have very visible nodes and internodes. It is typical of bamboo, corn and sugar cane.

The underground stems grow above the ground and are rich in nutritious substances. They are classified into rhizomes, tubers and bulbs.

Rhizomes are stems that have lateral buds and grow under the surface of the soil, emitting some leaves, like ginger and fern.

Tubers are widely used in food because they store nutritious substances, such as, for example, potato.

Formed by modified stems and leaves, the bulb -like stem is generally round, with roots at the bottom; and in the posterior one, leaves with nutritious reserves. Some bulb-type stems are widely used in human food, such as garlic and onion.

Aquatic stems are those that develop in the water, such as water lily, water hyacinth, etc.

The tendrils are stem adaptations that serve to attach climbing plants. Upon finding a suitable substrate, the tendril attaches itself to it and wraps itself around it. These adaptations are spring-shaped, which prevents them from breaking easily.

The thorn is an adaptation that is characterized by being very resistant and having a very sharp tip. It has the function of protecting the plant, keeping away predators that could damage it. The thorns are attached to the inner tissues of the stem, so it is more difficult to remove them from the plant. Some plants that have thorns are the lemon tree and the orange tree. It is important to remember that rose bushes do not have true thorns, but thorns, which can be easily removed from the plant.

In nature we find some stems that are green and most of the time flat. These stems, called cladodes, are adapted to carry out photosynthesis and generally store water. Vegetables that have this type of stem lost their leaves during their evolution, turning them into thorns to prevent water loss to the environment. These stems are typical of dry climates, as in cacti.

Figure showing the rhizophores and cladodes

The rhizophore is a type of stem that has positive gravitropism, that is, it develops towards the ground, most often forming adventitious roots. It is common to find this type of stem in mangroves.

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