Zantedeschia aethiopica vs arum lily

Zantedeschia aethiopica

arum lily

noun
  • Any of several flowering plants, of the family Araceae, but especially Zantedeschia aethiopica, the calla lily that has a showy white spathe. 

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