aroid vs calla lily

aroid

noun
  • Any plant of the family Araceae, found chiefly in the tropics. 

calla lily

noun
  • A flower of one of these plants. 

  • A common name for certain flowering plants in the genus Zantedeschia; not related to either the genus Calla or the true lilies (Liliaceae) 

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