pocan vs winterberry

pocan

noun
  • The poke, Phytolacca americana (formerly Phytolacca decandra). 

winterberry

noun
  • The fruit of this plant. 

  • A species of holly native to the United States and Canada and producing red berries, Ilex verticillata. 

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