Trees in the Legume Family

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 used as a coffee substitute, but it is now known that there are toxins in the seeds that make this a bad idea. The Black Locust produces a lot of seed pods and is considered to be invasive in certain environments.

Another distinctive feature of these trees is their flower. The flowers of the Yellowwood and Black Locust are fragrant and hang in long, drooping, clusters, 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 are may be the biggest of any tree found in Ontario and are on the tree for a shorter time than other deciduous trees.

Black Locust
(Robinia pseudoacacia)

This member of the Fabaceae family is native to the eastern US, but is widely planted and naturalized in Southern Canada. The leaves are alternate and pinnate with spines at the base of each leaf. The showy, fragrant, pea-like flowers appear about a month after the leaves. Small flat pods hold several seeds and remain on the tree through the winter. The tree is often planted to reforest gravel pits where few other trees would survive. The wood is used for fence posts.

Yellowwood
(Cladrastis lutea)

A member of the Fabaceae family, this tree is rare in its natural range- North Carolina, Kentucky and Tennessee- but is found too in milder parts of Canada. The pale green-blue leaves are elliptic, alternate and pinnately compound. Bark is smooth and grey like beech, but unlike beech often is covered in lichen or moss. Large clusters of fragrant white flowers hang from tips of new shoots in late spring and, like other legume, develop into flat pods. It is named for its yellow heartwood.

Kentucky Coffeetree
(Gymnogladus dioicus “Espresso”)

This large Carolinian tree is a member of the Fabaceae family and sub-family Cassia. The dark green shiny leaves, which develop late and drop early, are doubly pinnate and cascade on 3-9 pairs of branches on a central stem. The young bark breaks in to scaly ridges and the mature park has small curled scales. Like other members of the legume family, it produces large pods which stay on the tree through the winter. In spite of the name, the bitter husks are not edible. This cultivar has been bred to eliminate the pods, which some consider messy.

Artwork by Julian Mulock