What vegetable was called the edible stone by spanish?

The vegetable called the "edible stone" by the Spanish is the potato.

The potato, originally from the Andes region of South America, was a completely unknown food to Europeans before the Spanish conquest. Its appearance and texture, particularly when uncooked, likely led them to initially perceive it as a type of stone. The name "papa" (meaning "potato" in Spanish) is thought to have come from the indigenous Quechua word "papa."