While hiking in Cool Creek Park in Carmel, Indiana, I saw several green “monkey brains” scattered on the forest floor.
They came from an Osage Orange, which is a small deciduous tree or large shrub, that grows 30–50 feet tall. Their distinctive fruit is roughly spherical, bumpy, 3–6 inches in diameter and turns a bright yellow-green in the Fall.
The fruit secretes a sticky white latex when cut or damaged. Despite the name “orange,” it is instead a member of the mulberry family.
The trunk bark is brown to orange-brown and deeply furrowed with ridges. The glossy, lance-shaped leaves are arranged alternately and vary from dark to pale tender green. They have long, tapering tips and smooth to slightly wavy margins.
“Back in the day” these sharp-thorned shrubs were planted as cattle-deterring hedges before the introduction of barbed wire and afterward became an important source of fence posts.
This intriguing plant is also known as Hedge Apple, Horse Apple, Bodark, Bow-wood, Yellow-wood and Mock Orange.