Aaron's rod vs ocotillo

Aaron's rod

noun
  • Goldenrod, the Solidago genus of North American plants with yellow flowers. 

  • Hylotelephium telephium (syn. Sedum telephium; orpine, livelong, or live-forever). 

  • A rod-shaped molding decorated with an entwined snake, and sometimes leaves, vines, and/or scrolls. 

  • Verbascum thapsus, the great mullein, common mullein, or hag-taper. 

ocotillo

noun
  • Any of various succulent plants, not closely related to the cactus, in genus Fouquieria, especially Fouquieria splendens, living in Central America or the southwest United States. 

How often have the words Aaron's rod and ocotillo occurred in a corpus of books? (source: Google Ngram Viewer )