Chinese boxthorn vs Chinese wolfberry

Chinese boxthorn

noun
  • Synonym of Chinese wolfberry 

Chinese wolfberry

noun
  • Either of two Chinese species of spiny shrub in the nightshade family, Lycium barbarum and Lycium chinense, and their edible fruits, which are used in East Asian traditional medicine. 

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