A dichotomous key leads you through a series of questions about the plant you’re trying to identify. Each question makes you chose between two possibilities (dichotomous means dividing in two), and each choice brings you closer to the final answer. In Tree Finder, for instance, the first question is, “Does the tree have needles or leaves?” Key guides encourage close observation of plant structures and help you learn which plants are closely related to each other. Many educators believe dichotomous keys are the best tools for learning to identify plants.

Here’s why:

Using a key will teach you how to identify plants. Flipping through a picture book won’t. The key shows you what features to look for when you’re trying to tell one plant from another.

As you look closely at plants and work your way step-by-step through the key, you will learn to recognize closely related plants. Plants, just like people, have certain features in common with their relatives.

After you’ve been identifying plants for a while, when you come across a new flower, you may not know the species, but often you’ll find you recognize it as a mint, or a member of the sunflower family, or a lily. You won’t learn flower families by using a book that groups flowers by color. You may want to consult bigger books (or other sources) with color photos at home, and put the Finders books in your pocket or pack to take into the field.

Except for very conspicuous, easy-to-identify flowers, line drawings are actually more useful for identification purposes than color photos. Line drawings pare down the information contained in an illustration to the essentials, showing the features that are important for identification.

Our plant keys are sophisticated identification guides intended for use by adults and youth. Based on feedback from teachers, Scout leaders, and others, we generally recommend our books for use by 4th graders and older; the Tree Finders and the animal books are often used by younger children, with adult guidance.