bellflower vs campanula

bellflower

noun
  • Any flowering plants in the genus Campanula. 

  • A flower of one of these plants, which is shaped like a bell. 

  • Flowering plants in the genera, Campanulastrum, Codonopsis, or Platycodon, in the family Campanulaceae. 

  • Any flowering plant in genus Uvularia. 

campanula

noun
  • Any plant of the genus Campanula. 

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