lizard's tail vs water dragon

lizard's tail

noun
  • Used other than figuratively or idiomatically: see lizard, tail. 

  • Houttuynia cordata, chameleon plant, a herbaceous perennial plant native to Japan, Korea, southern China and Southeast Asia. 

  • Crassula muscosa, rattail crassula, a succulent plant native to South Africa 

  • Saururus cernuus, a medicinal and ornamental plant native to eastern North America. 

water dragon

noun
  • The lizard's tail plant (Saururus cernuus) 

  • Any of various agamid lizards of eastern Asia and Australasia, including the genera Physignathus, Intellagama, and Tropicagama, all of subfamily Amphibolurinae. 

  • A marsh marigold (Caltha palustris) 

  • A knucker, a lizard of English folklore. 

How often have the words lizard's tail and water dragon occurred in a corpus of books? (source: Google Ngram Viewer )