These are called Osage Orange or “Hedge Balls”. Information below taken from the web:
Osage Orange (Maclura pomifera) is a relatively small, unusually twisted, and frequently multitrunked tree with a small natural range in northern Texas, southeastern Oklahoma, and neighboring parts of Arkansas that roughly coincides with the historical home of the Osage Indians. Because they and other native groups used its wood to make bows, French explorers called the tree “bois d’arc,” and it is still sometimes referred to colloquially as “bodarc” or “bodock.” The range of the Osage orange expanded dramatically between 1840 and 1880 when, before the development of barbed wire, it was seen as the best and cheapest way to control livestock on the Great Plains. When planted close together and appropriately pruned, its branches and spiny thorns make a nearly impenetrable hedge able to turn away any animal larger than a bird or a rabbit. While it remains common in Illinois, Iowa, Missouri, Kansas, and Nebraska and present even in many eastern states, Osage orange fell from general use as cheaper fencing materials became available in the late nineteenth century.