Groundapple

It was a chesol deer, tawny as the Plains grasses when they flowered. A number of other wolves – five, six – followed them; these carried groundapples in their mouths.

Source: wiktionary

It's a change of scenery, at least." He picked up a ground apple. "What else do you have in there?"

Source: wiktionary

"Why, it is a ground-apple," and taking it from her he cut off a piece and put it in his mouth. In an instant, he cried: "You vixen! you knew that was Indian turnip - the most infernal thing that ever grew in a civilized country."

Source: wiktionary

If the child had formerly lived in a country where apples grew, but potatoes did not, the first time he saw a potato he would probably call it a ground-apple.

Source: wiktionary