To effectively identify plants, it helps to become familiar with their specific characteristics such as size, leaf formations, and flowers. Proper identification is useful in understanding how a particular plant grows and how to care for it. With some plants, such as trees, identification may not be as simple as looking at their flowers. This is especially true of tree seedlings, trees that have long since passed the initial blooming stage or trees that have no blooms at all. The term pinnate, meaning a feather-like or divided leaf pattern, can help in this identification.
For this reason, it’s often easier to look towards the leaves in order to determine a tree’s identity, such as with pinnate leaves. In fact, leaves are often the basis for plant identification. Leaves typically have two parts: the blade and the stalk, or petiole. The stalk attaches the blade to the plant stem or branch. Leaves may have a single undivided blade or one that is divided into parts.
The most common features used in leaf identification are simple and compound leaves. In simple leaves, the blade is not divided into leaflets, whereas compound leaves are. Simple leaves have one leaf blade, with or without a stalk. Compound leaves have more than one leaf blade with or without complex stalks.
When trying to identify a plant through its leaves, it is usually necessary to examine the leaf characteristics. As with many plants, trees of the same species share the same or similar characteristics such as size, shape, and color. However, these characteristics will vary from one tree to another in different species. Leaf edges, for example, may vary from smooth to jagged.
This is the reason why leaf identification is important, and this is where the term pinnate comes in. The veining characteristic of leaves helps determine identity. For instance, parallel-veined leaves run the same distance to each other. Pinnate leaves have a central midrib with side veins. This term is also used to describe the feathery-like features along the sides of the stalk. Palmate leaves, on the other hand, branch out from different points.
Generally, all simple leaves have the same parts. Simple tree leaves include elms, maples, oaks, and dogwoods. An oak leaf is a good example of a simple pinnate leaf. Pinnately compound leaves have several leaflets that grow from several places along the stalk. An ash tree provides a good example of leaves that are pinnately compound. Many other trees have pinnate leaves that are compound, including hickory, walnut, and locust trees.