These three trees belong to a huge family of flowering plants that are part of the Fabaceae (formerly Leguminosae) family that includes peas, beans, and legumes. 

A common feature of members of this family is the seed, encased in hard pods and similar in shape to pea pods. The Kentucky Coffeetree seeds are large, round, and dark brown. It is thought that they were considered as a coffee substitute, but it is now known that there are toxins in the seeds that make this a bad idea.

Another distinctive feature of these trees is their flower, which may not show until the tree is between eight to ten years old. The flowers of the Yellowwood and Black Locust are fragrant and hang in long, drooping, clusters, as found on Wisteria plants, known as racemes. The Kentucky Coffeetree flower, while less distinct, is interesting because the trees are either male or female, and require pollination, usually by bees, to produce fertile seeds. Its leaves may be the biggest of any tree found in Ontario and are on the tree for a shorter time than other deciduous trees.