Question

What are the parts of a leaf?

Answer 1

Most leaves have two main parts: (1) the blade and (2) the petiole, or leaf stalk. The leaves of some kinds of plants also have a third part, called the stipules.

The Blade, or lamina, is the broad, flat part of the leaf. Photosynthesis occurs in the blade, which has many green food-making cells. Leaf blades differ from one another in several ways: (1) the types of edges, (2) the patterns of the veins, and (3) the number of blades per leaf.

The Petiole is the stem like part of the leaf that joins the blade to the stem. Within a petiole are tiny tubes that connect with the veins in the blade. Some of the tubes carry water into the leaf. Others carry away food that the leaf has made. In many trees and shrubs, the petioles bend in such a way that the blades receive the most sunlight, thus assuring that few leaves are shaded by other leaves. The petiole also provides a flexible "handle" that enables the blade to twist in the wind and so avoid damage.

The Stipules are two small flaps that grow at the base of the petiole of some plants. In some plants, the stipules grow quickly, enclosing and protecting the young blade as it develops. Some stipules, such as those of willows and certain cherry trees, produce substances that prevent insects from attacking the developing leaf.