Poncirus trifoliata vs wild orange

Poncirus trifoliata

wild orange

noun
  • Capparis mitchellii, a non-citrus plant species that contains notable amounts of vitamin C. 

  • Several species of wild Citrus fruit, especially Citrus macroptera. 

How often have the words Poncirus trifoliata and wild orange occurred in a corpus of books? (source: Google Ngram Viewer )