The Osage orange tree is known for the large, yellow-green fruits that carpet the ground beneath it every fall. The fruits are anachronistic—they evolved millions of years ago in a different environment, when large animals like mammoths and mastodons may have eaten the fruits and helped disperse the seeds. Today, squirrels appear to be the only animals in the Arboretum’s landscape interested in the fruits. In spring, the plant grows light green leaves, which deepen in the summer and yellow in the fall, when the leaves and fruits drop. In winter, the tree’s deeply grooved, rot-resistant bark and thorns are visible.