horse chestnut vs rufous

horse chestnut

noun
  • The large nutlike seed of these trees. 

  • Any of several tree species of genus Aesculus, especially Aesculus hippocastanum, common in temperate northern hemisphere. 

rufous

noun
  • A reddish-brown colour, as of rust. 

adj
  • of a reddish colour 

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