Types of leaves and their functions (photo)

No matter how many trees on our planet, with various forms of crowns and the very foliage, they all take care of one thing - cleaning the Earth's air of carbon dioxide, which in unheard-of quantities throws mankind, wildlife, and various techniques into the environment. There is a lot of scientific and cognitive literature devoted specifically to this section of botany - "Kinds of leaves". The appearance of a tree or a bush a person can change, giving any, even the most bizarre, form. But the species of leaves of trees and plants for millennia remain unchanged.

Parts of the "body" sheet

Leaves are an integral part of the trunk system of any tree, shrub or plant. The constituent parts of the sheet have their names: plate, petiole, stipules.

The plate is the largest part of the sheet, it is flat in appearance and has a variety of shapes, which we will discuss later.

A petiole is, more simply, a stalk, thanks to which the plate of a leaf is attached to a branch. In some plants, the petiole is very small or absent.

Stipules are the so-called appendages of the leaf that are at its base. Very few people saw and know this part of the sheet. The fact is that in most plants stipules fall off before the leaf unfolds completely. An exception is only some species, acacia for example.

In botany, different types of leaves are classified. The photos are shown below.

The most common are leaves ordinary (or simple). These are leaf species that consist of a single leaf blade. It can be as practically even, round, and dissected, multifaceted, as in oak or potatoes. Simple leaves are divided into three subspecies: whole, lobed and dissected.

Plants that have whole leaves

Speaking about the types of trees, it is worth mentioning first of all birches. It is not for nothing that this tree is the symbol of our country. The birch is widespread throughout the Northern Hemisphere of the Earth, but a larger cluster of these trees is located on the territory of Russia. The birch leaf is simple, one-piece, slightly curved, with a serrated edge. Plates of uniform green color, veins - in tone. In autumn, as is known, the foliage of birches acquires a yellow shade.

This same species includes foliage and another tree common in Russia - the apple tree. The leaf of this fruit tree is larger, but it has the same characteristics: it is one-piece, slightly jagged at the edges, of even color.

Aspen, lilac, poplar, elm and other plants have exactly the same kind of leaf. However, only from the botanical point of view they are similar to each other, external differences, of course, are available.

The second subspecies is lobate. This kind of leaves is inherent in some maple trees. A living example is a sheet depicted on a Canadian flag. Leaves are referred to lobed, if the "jagged" on their edges do not exceed one-fourth of the total area.

This is the blade-type simple sheet. If you seriously become interested in the topic "Types of maple leaves," the study may take many years. These trees number more than 50 species, each of which is remarkable not only for its habitat, but for its appearance: from the height, the shape of the branches and trunk to the type of leaves. We will not dwell on this in detail.

The third subspecies of simple leaves is the leaves dissected. This species includes leaves that have a dissection of more than one quarter of the leaf. For example, like a dandelion, tansy. Mostly this type is observed in medicinal plants and flowers.

Leaves with a complex structure

Types of leaves of trees and plants form the second large group - complex. They are called complex because they have several plates. They are conventionally divided into triple-syllabic, palatosyllabic and pinnate.

Representatives of the flora, having triple-complex leaves - garden strawberries and wild strawberries, clover. Their distinguishing feature is three leaves on one stalk. The belief about clover with four leaves passes from generation to generation. It is not possible to find such a plant.

To palchatosyllabic there are leaves of horse chestnut, garden lupine.

To the pinnatus - leaves of raspberries, mountain ash, peas. They also have their subspecies: those that have two leaflets at the end of the stalk, for example, like peas, and the odd-numbered ones - a rose, are one of the parodermorous, and the petiole ends with one.

Types of leaves of plants (plate shape)

The leaves are also classified according to the type of leaf plate:

1. Rounded.

These include a houseplant such as a violet, as well as a garden nasturtium, aspen.

2. Oval.

The type of leaves is found in the elm, hazel.

3. Lancet.

Prevail among the trees and bushes of the family of willow trees, as well as in the bush called silver loch.

4. Egg-shaped.

This name is worn by the leaves of all known plantain

5. Linear.

This type of leaf prevails in cereals, for example, in rye.

The form of the base of the leaf is a separate attribute for classification. Based on this parameter. Leaves are:

• Heart-shaped (as in a lilac);
• Wedge shaped (sorrel);
• Arrowhead (arrowhead).

The shape of the top of the sheet is dull, pointed, round, bilobate.

A separate topic - venation

Now consider how the name of the leaf affects its venation.

Dicotyledonous plants are characterized by reticular venation. It can be of two types: palpate (when all the veins come out, like a bundle from one base) and pinnate (when the minor veins branch off from the main vein).

In monocotyledons, there is usually a parallel or arc venation. Parallel - for thinner leaves (leaves of wheat, cane), arc - on broad leaves (lilies of the valley).

Some interesting facts about the leaves

• The most delicate leaves are in ferns called adiantum-thin-leaved shrimps. There are simply no more of them in nature.
• The sharpest leaves - the grass is tangled. The local population says that such a grass is sharper than a knife.
• More than 45 million leaves are found in cypress.
• More than two sheets never grows on velvichie.
• Water lily "victoria" has leaves with a diameter of more than two meters.
• The length of the palm leaf of Rafia is 20 meters.
• Not all plants drop foliage for the winter. There are those who call evergreens.

Types and color of leaves

Strangely enough, but the color of the sheet often does not envy either its shape or location. Just a plant is inherent in this color, that's all.

What is the color of the sheet? In summer almost all plants are colored green due to the presence in their tissues of a special pigment - chlorophyll. This substance helps plants maintain their vital activity, with its help the plant makes an unprecedented trick: in the daytime, it synthesizes glucose from carbon dioxide. In turn, glucose becomes a building material for all essential nutrients.

Why do the leaves turn yellow?

In addition to chlorophyll, plant leaves contain other coloring substances, such as xanthophylls, carotene, anthocyanins. In summer, their effect on the coloring is very minimal, since the concentration of chlorophyll in the tissues of the plant is thousands of times higher. But with the onset of autumn, all life processes begin to fade, the amount of chlorophyll begins to decrease. It is noteworthy that it is by light that the holophyll collapses much faster. Therefore, if the autumn is sunny and warm, foliage quickly turns yellow and falls off.