fennelflower vs love-in-a-mist

fennelflower

noun
  • Nigella sativa, an annual flowering plant native to south and southwest Asia. 

  • Nigella damascena, ragged lady 

love-in-a-mist

noun
  • Nigella damascena, an annual flowering plant of the genus Nigella, the blooms of which are generally blue in colour, though also found in shades of pink, white or pale purple. 

How often have the words fennelflower and love-in-a-mist occurred in a corpus of books? (source: Google Ngram Viewer )