batata vs tuber

batata

noun
  • sweet potato (plant) 

  • sweet potato (foodstuff) 

tuber

noun
  • A fleshy, thickened underground stem of a plant, usually containing stored starch, for example a potato or arrowroot. 

  • A thickened rootstock. 

  • A rounded, protuberant structure in a human or animal body. 

How often have the words batata and tuber occurred in a corpus of books? (source: Google Ngram Viewer )