green dragon vs thorn apple

green dragon

noun
  • A tincture of cannabis, typically made by soaking the flowers, leaves, or stems in ethyl alcohol. 

  • Used other than figuratively or idiomatically: see green, dragon. 

  • Any of several plants in the family Araceae, including the North American species Arisaema dracontium and the Asian genus Pinellia. 

thorn apple

noun
  • Jimsonweed (Datura stramonium), an annual plant having white flowers and prickly capsules. 

  • Datura spp., especially 

  • Crataegus spp. 

  • Solanum incanum, native to Africa and Asia 

How often have the words green dragon and thorn apple occurred in a corpus of books? (source: Google Ngram Viewer )