Dichotomous Keys
What is That?
Dichotomous keys can help identify the life around you.
"Dichotomy" is a contrast between two things, so dichotomous keys continually ask statements with two choices that lead you to a—usually tentative—species identification. Following an identification key is an excellent way to look more closely and connect with the world around you.
The Key Facts of Dichotomous Keys
Scientists estimate there are about 2,300 vascular plant species in Wisconsin; the keys help narrow your search.
Check Your Identification
Does the geographic range make sense? Do available images look right? By checking your identification, you're collecting more accurate data.
Some Work Better Than Others
Dichotomous keys are by nature artificial (they don’t reflect evolution, but are a product of classification expertise) and some “work” better than others.
Inspect Carefully
Depending on the taxa of interest, a 10x hand lens will be required (this applies to most vascular plants) or a stereoscope or compound microscope (for, e.g., bryophytes).
Our Dichotomous Keys
Both of these keys were built by Gary Fewless, and are incredibly useful for our Western Great Lakes flora.
Ferns and Lycophytes of Wisconsin
Unlike other plants, ferns and lycophytes don't have stems that extend out. Instead, leaves ascend directly from an underground stem, or have a very short stem near the surface.
Trees of Wisconsin
More than 130 species of trees grow outside of cultivation in Wisconsin. Use the key to help identify trees and shrubs in your environment.
Ask an Expert
Herbarium curator Keir Wefferling is passionate about plant life in Wisconsin; even when he's not working, he's botanizing, playing outside, or reading about moss or Wisconsin's natural plant communities. If you have questions about dichotomous keys, he can help.