Field Work




Go outside

Look around. Somewhere nearby is almost certainly a tree. While it's often obvious, there is no universal definition that clearly delineates shrubs from trees. We'll use the working definition below to help guide our exploration-- but when in doubt, choose larger plants. That will also help remove some of the complications presented by immature trees which can vary considerably from mature specimens.

Generally, trees are over 20 feet tall and have trunks more than 2 inches in diameter at 4.5 feet about the ground. Shrubs are smaller than trees and often have many small, woody, bark covered stems rising from the base.

National Park Service

Plants, and trees in particular, have leaves. So we'll start by looking at the leaves. In this case we're going to find a tree with broad flat leaves rather than the needles/scales present in conifers. Depending on the season you may need to look on the ground around the tree to find representative leaves.

Once you've found a tree that interests you, progress through the dichotomous key choices below. While this process is not meant to reach a definitive identification, each selection will add information to the image you submit at the end. If you would like to attempt to fully identify your tree, you can use the Virginia Department of Forestry's Common Native Trees of Virginia Identification Guide.

Opposite vs Alternate

The arrangement of leaves on the stem/branch can be opposite (in pairs, directly across from each other on the branch) or alternate (singly and alternate from one side of the stem/branch to the other)

Choose the arrangement that is most like your tree. If you are having trouble determining whether the leaves are alternate or opposite, sometimes you can look at the twigs on a branch. As each twig originates from where a leaf used to be, their pattern should be the same as the leaf pattern. Always look at more then one leaf/twig/branch as sometimes they can be broken off during growth and this can alter the pattern.

Opposite - Compound vs Simple

You have found an opposite arrangement.

The next step is to look more closely at a single leaf to determine if it is compound or simple. This has more to do with the structure of the leaf itself than with the position of the leaf on the stem. One of the defining characterstics of a leaf is that at the base of the leaf stem (petiole) there is a small bud called the axillary bud. Sometimes this bud is covered by the petiole so make sure you look carefully.

If there is no axillary bud at the base of the petiole, then the structure is not a leaf but rather a leaflet and the leaf, as a whole, is compound.

Alternate - Compound vs Simple

You have found an alternate arrangement.

The next step is to look more closely at a single leaf to determine if it is compound or simple. This has more to do with the structure of the leaf itself than with the position of the leaf on the stem. One of the defining characterstics of a leaf is that at the base of the leaf stem (petiole), there is a small bud called the axillary bud. Sometimes this bud is covered by the petiole so make sure you look carefully.

If there is no axillary bud at the base of the petiole, then the structure is not a leaf but rather a leaflet and the leaf, as a whole, is compound. Compound leaves are composed of multiple leaflets, while simple leaves do not have leaflets at all.

Opposite & Compound - Pinnate vs Palmate

You have found an opposite and compound specimen.

Pinnate means that the veins resemble a feather: one main vein with many smaller veins branching off.

The palmate vein pattern looks roughly like the outspread fingers of your hand. All of the main veins in the leaf originate at the base of the leaf and fan outward.

Opposite & Simple - Lobed vs Unlobe

You have found an opposite and simple specimen.

Lobes are large and distinct indentations of the margin of the leaf. The depth/degree of the lobe, referred to as the sinus, can be useful in identifying a plant, as can the number of lobes on the leaf.

Leaves without lobes will have an edge devoid of major indentations.

Alternate & Simple - Lobed vs Unlobed

You have found an alternate and simple specimen.

Lobes are large and distinct indentations of the margin of the leaf. The depth/degree of the lobe, referred to as the sinus, can be useful in identifying a plant, as can the number of lobes on the leaf.

Leaves without lobes will have an edge devoid of major indentations.