Hackberry, Celtis occidentalis
Hackberry isn't commonly planted in yards and parks, but it's a great native tree for woods near creeks. It's related to elm but isn't quite so large and stately. It has distinctive warty bark. There are insects that often make galls in the leaves, and although they don't hurt the tree, they may partly account for the tree not being so popular in the urban landscape. Hackberry fruits aren't very big but they are extremely nutritious and relished by birds and other animals, including some people.