blackboy vs yacca

blackboy

noun
  • Any plant in the genus Xanthorrhoea, native to Australia. 

yacca

noun
  • Any of the various Australian perennial flowering plants of the genus Xanthorrhoea. 

  • Either of two large evergreens of the West Indies, Podocarpus coriaceus and Podocarpus purdicanus. 

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