Only the seeds of "hedge apples," formally known as Osage oranges, are edible by humans. There are approximately 200 small seeds contained in a slimy husk that are edible; the skin and core of the fruit are inedible.
Hedge apples are round fruits about 6 inches in diameter that have a green wrinkled surface. Hedge apples are commonly grown in the prairie areas of the United States, such as Oklahoma and Texas. Inside, the fruit is yellow and has a thick core surrounded by the seeds, which must be removed from the husk before eating. The "orange" name comes from the smell that the ripe fruit emit. Only female Osage orange trees bear fruit.