This dichotomous key can be used to help identify fern species found growing in the natural lands at Royal Botanical Gardens (Burlington, Ontario, Canada). The language of fern taxonomy and botany can be tricky for beginners, so a glossary is included. There you will find definitions and diagrams to assist in your work. Many of the steps in this key (and most others) refer to reproductive parts of the plant. Unfortunately, the presence of these traits is often seasonal. In addition, the growth habit can be very important. If you are collecting a fern specimen, always note whether it is growing in radial clusters, or if it is more randomly scattered. Ferns are typically easiest to identify in mid to late summer.
A note on pictures : This key includes several diagrams and photographs to assist in choosing a direction. However, the text should always be read carefully. Also note that the diagrams are usually meant to illustrate a single difference or point, and should not be looked at as depictions of particular fern species. In other words, do not simply look for the picture that looks most like your fern specimen.