The Osage Orange tree (species "Maclura pomifera) is a small to medium size tree native to the United States. It is sometimes also called the Osage Apple, Hedge Apple or Wild Orange. The fruit of this tree as you can see from the pictures is about the size of a large orange although the color is more of a greenish yellow. The surface of the fruit has a sort of brain like appearance and is covered with fine, strangly hairs (see image below).
In contrast to what its name seems to indicate thefruit of the Osage Orange is not edible. Upon cutting one open I found that the inside was quite sappy and full of seeds similar to citris seeds as can be appreciated in the image below. The inside of the fruit is quite dense and its smell is not at all appealing.
The leaves are simple in shape and dark, glossy green in color. At the base of the leaf stem there are short, sharp thorns which is possibly why this species has been used as a cattle or protetion hedge in the past. Being from the Mulberry family the leaves of this tree are a source of food for silk worms.
When this tree is allowed to grow straight (not the case when it is grown as a hedge) it produces a quality wood that is hard and rot resistant. It has been used for making bows as well as for tool handles and fence posts.
(information taken from "Árboles Madrileños" by Antonio López Lillo and Antonio López Santalla, 2007 Obra Social Caja Madrid)
Check out an Osage Orange tree by the Eiffel Tower in Paris!