This peculiar looking "fruit" is known as an Osage orange or a hedge apple, Maclura pomifera. The tree is a native of the central states and one of the few trees to be found in the dry plains. I spent much time as a child in Missouri climbing among it's thorny branches. It had become a popular plant for farmers to grow in hedgerows, a living fence to keep cattle from roaming. This specimen was photographed at the Montpelier estate where it was probably introduced by the gardener.
