Japanese medlar vs loquat

Japanese medlar

noun
  • The loquat. Eriobotrya japonica, which was formerly thought to be closely related to the medlar 

loquat

noun
  • The Eriobotrya japonica tree. 

  • The fruit of this tree. It is as large as a small plum, but grows in clusters, and contains four or five large seeds. 

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