No matter how many trees on our planet are, with various forms of crowns and foliage itself, they all care about one thing - cleaning the Earth’s air from carbon dioxide, which in unprecedented amounts emits humanity, the animal world, various techniques into the environment. There is a lot of scientific and informative literature devoted to this particular section of botany - "Types of Leaves". A person can change the appearance of a tree or shrub, giving any, even the most bizarre, shape. But the types of leaves of trees and plants for thousands of years remain unchanged.
Parts of the "body" of the sheet
Leaves are an integral part of the stem system of any tree, shrub or plant. The components of the leaf have their own names: plate, petiole, stipules.
The plate is the largest part of the sheet, it is flat in appearance and has a variety of forms, which we will talk about later.
Petiole is, more simply, a stalk thanks to which a leaf plate is attached to a branch. In some plants the petiole is very small or absent.
Stipules are the so-called leaf appendages, which are located at its base. Few have seen and know this part of the sheet. The fact is that in most plants stipules fall away even before the leaf unfolds completely. The exception is only some species, acacia for example.
In botany, various types of leaves are classified. Photos are presented below.
The most common are ordinary (or simple) leaves. These are leaf species that consist of a single leaf blade. It can be almost even, rounded, or dissected, multifaceted, like oak or potato. Simple leaves are divided into three subspecies: whole, lobed and dissected.
Whole leaf plants
Speaking about the types of trees, it is worth mentioning primarily birch trees. No wonder it is this tree that is the symbol of our country. Birch is widespread throughout the Northern hemisphere of the Earth, but a larger accumulation of these trees is located on the territory of Russia. The birch leaf is simple, solid, slightly curved, with a serrated edge. Plates of uniform green color, veins - in tone. In the fall, as you know, birch foliage acquires a yellow tint.
The foliage of another tree common in Russia, the apple tree, also belongs to this species. The leaf of this fruit tree is larger, but has the same characteristics: it is solid, slightly serrated at the edges, even in color.
Aspen, lilac, poplar, elm and other plants have exactly the same kind of leaf. However, only from a botanical point of view they are similar to each other, of course, there are external differences.
The second subspecies is lobed. This kind of leaves is inherent in some maple trees. A living example is the leaf depicted on the Canadian flag. Leaves are classified as lobed if the “notches” at their edges do not exceed one fourth of the total area.
This is exactly a lobed simple leaf. If you are seriously interested in the topic "Types of Maple Leaves", then the study can take many years. There are more than 50 species of these trees, each of which is remarkable not only for its habitat, but also for its appearance: from the height, the shape of the branches and trunk, and ending with the appearance of the leaves. We will not dwell on this in detail.
The third subspecies of simple leaves is dissected leaves. This species includes leaves that have dissections of more than one quarter of the leaf. For example, like a dandelion, tansy. Mostly this type is observed in medicinal plants and flowers.
Complex Leaves
Species of leaves of trees and plants form the second large group - complex. They are called complex because they have several records. They are conditionally divided into ternary, palmate and cirrus.
Representatives of the flora having ternate leaves - garden strawberries and wild strawberries, clover. Their distinguishing feature is three leaflets on one petiole. The four-leaf clover belief passes from generation to generation. To find such a plant is not possible.
To palmate include leaves of horse chestnut, garden lupine.
Cirrus - leaves of raspberries, mountain ash, peas. They also have their own subspecies: the paranormal ones are those where there are two leaves at the end of the stalk, for example, like peas, and the unpaired feathers have a rose, and its petiole ends with one.
Types of plant leaves (plate shape)
Leaves are also classified by the type of leaf plate:
1. Rounded.
These include a houseplant such as violet, as well as garden nasturtium, aspen.
2. Oval.
The type of leaves is found in elm, hazel.
3. Lanceolate.
Prevail among the trees and shrubs of the willow family, as well as in a shrub called silver goof.
4. Ovoid.
This name is the leaves of the well-known plantain.
5. Linear.
This type of leaf prevails in cereals, for example, in rye.
The shape of the base of the sheet is a separate feature for classification. Based on this parameter. leaves are:
- heart-shaped (like lilacs);
- wedge-shaped (sorrel);
- arrow-shaped (arrowhead).
The shape of the top of the leaf is blunt, pointed, rounded, bilobate.
Separate topic - venation
Now consider how the venation affects the name of the sheet.
Dicotyledonous plants are characterized by net venation. It can be of two types: palmate (when all veins come out, like a bundle from one base) and cirrus (when smaller veins branch from the main vein).
In monocotyledonous plants, parallel or arc venation is usually found. Parallel - on thinner leaves (leaves of wheat, reeds), arc - on wide leaves (lilies of the valley).
Some interesting leaf facts
- The most delicate leaves are found in a fern called adiantum-leaved leaf. Thinner they simply are not in nature.
- The sharpest leaves are near the putang grass. The local population says that such grass is sharper than a knife.
- More than 45 million leaves are in cypress.
- More than two sheets never grow on velvichy.
- Water lily "Victoria" has leaves with a diameter of more than two meters.
- The leaf length of the Rafia palm tree is 20 meters.
- Not all plants dump foliage for the winter. There are those called evergreens.
Types and color of leaves
Oddly enough, but the color of the sheet often does not depend on either its shape or location. It is just this color that is inherent in the plant, that’s all.
What is the color of the sheet made up of? In the summer, almost all plants are painted green due to the presence of a special pigment in their tissues - chlorophyll. This substance helps plants maintain their vitality, with its help the plant performs an unprecedented focus: in the daytime it synthesizes glucose from carbon dioxide. In turn, glucose becomes the building block for all essential nutrients.
