It’s a bad translation using a more modern meaning of “erdapfel” instead of a medieval one. Could easily be a very local colloquialism instead of a widespread name.
To my eye it looks like a melon or gourd plant. It’s definitely not a tuber (the next drawing shows an underground bulb).
To my eye it looks like a melon or gourd plant. It’s definitely not a tuber (the next drawing shows an underground bulb).