Indian turnip vs memory root

Indian turnip

noun
  • Arisaema triphyllum 

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

memory root

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

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