oxtongue vs ragweed

oxtongue

noun
  • A flowering plant of the genus Anchusa, especially Anchusa officinalis (true alkanet). 

  • Beef tongue (a foodstuff). 

  • A flowering plant of the genus Picris, especially Picris echioides (bristly oxtongue). 

ragweed

noun
  • A plant of the genus Ambrosia. These weeds are particularly noted for producing pollen which people with hay fever are allergic to. 

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