goat's-beard vs quickthorn

goat's-beard

noun
  • A woodland plant of the family Rosaceae, Aruncus dioicus. 

  • A yellow-flowered Eurasian plant, of the genus Tragopogon. 

quickthorn

noun
  • The may-tree, any species of Crataegus or the species Crataegus monogyna. 

How often have the words goat's-beard and quickthorn occurred in a corpus of books? (source: Google Ngram Viewer )