cobra lily vs memory root

cobra lily

noun
  • The plant Chasmanthe aethiopica. 

  • Any plant in the genus Arisaema spread in eastern Asia, eastern Africa and eastern North America 

  • A carnivorous plant native to northern California and southern Oregon, Darlingtonia californica 

memory root

noun
  • Synonym of Jack-in-the-pulpit (“the plant Arisaema triphyllum”) 

How often have the words cobra lily and memory root occurred in a corpus of books? (source: Google Ngram Viewer )