lingonberry vs pyrola

lingonberry

noun
  • The berry of this shrub. 

  • A berry-bearing shrub, Vaccinium vitis-idaea, native to the cool temperate areas of the Northern Hemisphere. 

pyrola

noun
  • Any of the genus Pyrola of wintergreens. 

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