Indian turnip vs cobra lily

Indian turnip

noun
  • Used other than figuratively or idiomatically: see Indian, turnip. (also meaning Brassica rapa cultivars in India) 

  • Arisaema triphyllum 

cobra lily

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

  • The plant Chasmanthe aethiopica. 

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

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