Compound Leaf Identification
- Clusters of leaves each forming a compound leafgreen leaves 3 image by Kostyantyn Ivanyshen from Fotolia.com
Studying leaves is the primary way to identify trees. A few of the more common ones, such as maples and oaks, are readily identifiable, while with those less indigenous to a particular area, more examination is required to make a correct determination. Leaves fall into several categories, the two most important being their forms: simple or compound. Whereas a simple leaf is simply a single leaf on its stem attached to a twig or a branch, a compound leaf is a cluster made up of anywhere from three to several dozen leaflets attached by its stalk to a twig. - A cluster of compound leavesLeaves image by Lin from Fotolia.com
The stem of compound leaves supports multiple leaflets that may be singly compound, which indicates that they are arranged along a single stem; or they may be doubly compound, which means that the leaflets are arranged along a network of branched leaf stems. Examples of single compound leaves include walnuts and locusts, while tree species with doubly compound leaves include chinaberries and coffeetrees. Inspecting an entire compound leaf is crucial to determining its type, as examining just a detached leaflet could mistakenly suggest that it is a simple leaf. - An example of a palmate compound leafleaves 1 image by PictureDaddy from Fotolia.com
Compound leaves can also be categorized as being either pinnate, which means that the leaflets occur somewhat symmetrically along both sides of a stalk, or palmate (hand-like) in that the leaflets are arranged in the shape of a hand. Compound leaves, as most simple leaves, fall into additional categories that include wavy-edged, fine-toothed, coarse-toothed, single-toothed, double-toothed, feathered or fanned. Leaflets can be arranged along a stem in a perfectly opposite pattern or can be alternate, which means that each individual leaf made up of its several leaflets is located a slight distance above or below its facing leaf. - A sumac in fall colorred sumac branch image by Scott Slattery from Fotolia.com
The Staghorn Sumacs, for example, fall into the alternate compound leaf category, because their leaflets occur at intervals along the stalk. They are also good examples of feathered compound leaves. Compound leaves, as most simple leaves, fall into additional categories that include wavy-edged, fine-toothed, coarse-toothed, single-toothed, double-toothed, feathered or fanned. Leaflets can be arranged along a stem in a perfectly opposite pattern or can be alternate, which means that each individual leaf made up of its several leaflets is located a slight distance above or below its facing leaf. Other trees whose leaves are designated as compound include the Hop Tree, the Shagbark Hickory, the Black Locust, and the Carolina Ash. - A field guide: indispensible in leaf identificationpage in old book with shallow depth of field image by Nikolay Okhitin from Fotolia.com
Other than keen observation and good analytical skills, there is no other more useful aid in identifying compound leaves than a complete and illustrated field guide. Among the most useful is the "National Audubon Society Field Guide to Trees," published by Alfred R. Knopf, which includes several regional editions; "Peterson Field Guides," also available in several regional editions, published by Houghton Mifflin Company; and "Tree Finder: A Manual For the Identification of Trees By Their Leaves," published by the Nature Study Guild. Using one of these guides, compound leaf identification can be a rewarding and educational component of the study of the trees that beautify the world around us.
