arum vs calla

arum

noun
  • A flower or plant in the genus Arum 

calla

noun
  • The calla lily, Zantedeschia aethiopica. 

  • A marsh plant native to cooler areas throughout the northern hemisphere, Calla palustris, having pale green flowers in a white spathe. 

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