American winterberry vs black 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. 

black alder

noun
  • American winterberry, Ilex verticillata. 

  • Wood or other product of the tree. 

  • A tree (Alnus glutinosa), of many practical uses, growing in moist conditions in Europe. 

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