arum vs lily of the Nile

arum

noun

  • A flower or plant in the genus Arum 

lily of the Nile

noun

  • Zantedeschia aethiopica, a plant species in the family Araceae. 

  • Agapanthus praecox, a plant species in the family Alliaceae. 

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