moxa vs mugwort

moxa

noun
  • A woolly material obtained from the dried leaves of an Asian species of mugwort, such as Artemisia argyi, as used in moxibustion. 

  • Any other substance used in moxibustion. 

mugwort

noun
  • Artemisia vulgaris, traditionally used medicinally. 

  • Any of several aromatic plants of the genus Artemisia native to Europe and Asia. 

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