TYPES of SHEETS - Classification and Images

Leaves are one of the most visible and recognizable parts of plants, and are actually one of the most important as well. These are responsible for capturing sunlight and photosynthesis that gives energy to the plant, as well as plant respiration also occurs in them.

Due to the great importance that they have in most plants, there is a huge variety of types of leaves and characteristics. Therefore, there are also many different ways to classify them. If you want to learn more about Kind of leafs and its different classifications, join us in this interesting and practical article by Green Ecologist.

Types of leaves according to the petiole

The petiole is the part of the leaf that connects the blade, which is the wide part that we tend to recognize as the leaf itself, and the stem or branch. Thus, they can classify leaves according to petiole thus:

Petioled leaves They have a petiole that connects the blade to the plant. This petiole can have very different sizes depending on the specific characteristics of each plant.
The sessile or sitting leavesInstead, they do not have a petiole. In these cases, the blade arises directly from the stem or branch.

However, not all plants have to be exclusively petiolate or sessile leaves: there are some that have leaves of both types, depending on whether they are leaves on the stem or at the base.

Image: Slideshare

Types of leaves according to the division of the blade

As we explained above, The limb It is the most recognizable part of what we usually call the leaf, the broad and generally smooth area. The way the limbus divides or not is another kind of leaf classification.

Simple leaves They have a limb that is either not split at all, or it is, but its divisions do not reach the main nerve.
The divided or compound leavesOn the other hand, they show a limbus that divides completely up to the main nerve, giving the sensation of several limbs joined by a single petiole.

Image: Herbariosantiago5y6.blogspot

Types of leaves according to their shape

Actually, the most correct thing is to say that we classify them according to the morphology or shape of the blade, and not the leaf itself. It is one of the most visual and easy to identify classifications. The tTypes of leaves according to the shape of the blade are as follows:

Elliptical blade: As the name indicates, they are those whose shape traces an ellipsis, that is, an elongated or deformed circumference.
Lanceolate blade: They are those whose limbus shows a characteristic spearhead or simple arrowhead shape, with a wider base and a narrow and sharp point.
Acicular blade: the typical needles of most conifers, such as pine, are easy to recognize examples of this morphology.
Oval blade: They are similar to ellipticals, but somewhat wider at the base and with a sharper point.
Heart-shaped blade: similar to the way we usually represent hearts.
Sagittate leaf: This characteristic shape resembles the point of a halberd or a divided arrow, with a central point and two others open to the sides.
Linear sheet: these leaves look like ribbons, with straight, regular edges that extend. They tend to be narrow and long.

In the image you can see these shapes and some more.

Image: Pinterest

Types of leaves according to their edge

In addition to the previous classification, the shape that the edge of the leaf blade adopts can also be differentiated. Thus, the types of leaves according to the border of these are:

Whole sheet: Also called smooth leaves, the edge of whose blade extends in an uninterrupted line and in a straight way or with a constant curve are leaves.
Serrated blade: In these leaves, the blade takes the shape of saw teeth, which can be very different in size depending on the specific shape of each species.
Lobed or lobed leaf: these leaves create very marked irregularities in their contour, with projections and recesses of pronounced curved shapes.
Corrugated sheet: They present curvatures in their contour, but in a smoother and less pronounced way than in the lobed ones, without actually forming “arms”.

Image: UPC

Types of leaves according to their veins

You can find three main types of leaves according to their veins, differentiated in this way:

Penninervia leaf: They are the leaves that have a main vein, from which all the secondary veins start. It is the typical form adopted by most of the leaves that are represented.
Palminervia leaf: its name comes from the palm of the hand because of its similarity to it. From a central point the different nerves come out as if they were the fingers of the hand.
Sheet parallelinervia: its ribs extend in a near parallelism throughout the entire blade.

Now, thanks to knowing the different types of leaves, you can also learn How to identify trees and plants from their leaves.