American winterberry vs white alder

American winterberry

noun
  • Ilex verticillata, a species of holly native to eastern North America in the United States and southeast Canada, from Newfoundland west to Ontario and Minnesota, and south to Alabama. 

white alder

noun
  • American winterberry (Ilex verticillata). 

  • Grey alder (Alnus incana) 

How often have the words American winterberry and white alder occurred in a corpus of books? (source: Google Ngram Viewer )