damson vs violaceous

damson

adj

  • The color of the fruit of this tree, a very deep purple. 

noun

  • A subspecies of plum tree, Prunus domestica subsp. insititia, native to Eurasia. 

  • The edible fruit of this tree. 

violaceous

adj

  • Violet-colored. 

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