gunpowder tea vs tea plant

gunpowder tea

noun
  • A form of Chinese green tea in which each leaf has been rolled into a small round pellet. 

tea plant

noun
  • The bush Camellia sinensis, the leaves of which are picked, dried and used to make the beverage tea. 

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