Spanish moss vs beard moss

Spanish moss

noun
  • A gray epiphyte that hangs down from trees, Tillandsia usneoides, native to the southeastern US and throughout humid tropical and subtropical parts of the Americas. 

beard moss

noun
  • Any of several lichens, of the genus Usnea, that generally grow hanging from tree branches, resembling grey or greenish hair. 

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