Leaf Types
A Quick Guide to the Common Leaf Types
When you consider that there are over 275,000 different kinds of plants, it makes sense that there are more leaf types than you could ever imagine. Leaves are important to plants in many ways, from helping us identify the plant to using sunlight and the process of photosynthesis to create energy.
All leaf types have the same basic layering structure but they have different shapes, sizes, and vein patterns. Some leaf types have also adapted to survive in special environmental conditions, such as sand or rocky ledges. Generally, all leaves have a stalk, which is called the petiole, and a flat blade, which is known as the lamina. Leaves are living organisms upon which all life is dependent for its survival.
The leaf types of plants can be arranged in patterns, such as opposite, alternate or whorled, and they can have many different types of veins, which are known as vascular bundles. As leaves develop, they sometimes have to adjust to difficult environmental conditions, such as varying temperatures, humidity levels, soil types, and the availability of water or light.
Let’s look at some leaf types that have become more specialized due to environmental factors:
Buried Leaves--Some people refer to these leaf types as window leaves. That’s because only the small tip of a leaf is above the ground. It acts as a window, letting light in to complete the process of photosynthesis. The rest of the plant is buried in the soil, completely underground. You can find examples of this plant in the Carpetweed family. It is the way these plants have adapted to a very dry, sandy and windy desert environment.
Arid Leaves--These leaf types develop in hot and extremely dry conditions. The plants tend to grow leaves that are thicker than normal, or sometimes no leaves at all. There are plants that have no leaves in this type of environment, and they complete the process of photosynthesis in the plant stem instead of the leaf. The same kind of modification can also be found anywhere there is lack of water even if the temperature is cold. It sometimes happens with fir trees. Another good example is the compass plant. It is so named because the leaves of the plant face north/south to retain moisture.
Leaf tendrils--Some plants that are heavy or climbers have leaves that have adapted to this condition by becoming tendrils. They crawl along supporting the weight of the plant, and when they find anything solid they coil around it to anchor the plant.
Leaves that trap insects--These are very interesting plants that have acquired new ways to get the nutrients they need to survive. They do this by trapping insects and then dissolving and absorbing them. Most of the insect trapping plants are in wet areas, such as swamps. Among these plants are bladderworts and Venus flytraps.