arum vs bath sponge

arum

noun
  • A flower or plant in the genus Arum 

bath sponge

noun
  • A commercially used species of sponge (porifer, invertebrate of the phylum Porifera) found throughout the Mediterranean Sea, Spongia officinalis. 

  • A sponge, made from any material, that is used for cleaning the body while bathing. 

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