black raspberry vs blackcap raspberry

black raspberry

noun
  • A plant belonging to either of two closely related species, Rubus leucodermis or Rubus occidentalis, both native to North America. 

  • The fruit of any of these species. 

  • Rubus coreanus, native to Korea, Japan, and China 

blackcap raspberry

noun
  • Whitebark raspberry. 

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