jojoba vs pignut

jojoba

noun
  • A shrub native to the southwestern United States and to Mexico, Simmondsia chinensis: the only plant known to store liquid wax in its seed. 

pignut

noun
  • Simmondsia chinensis, jojoba. 

  • The edible tuber of Conopodium majus, native to western Europe. 

  • Any of various types of hickory or their fruits; a hognut. 

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