pappus vs tussock

pappus

noun
  • The markedly reduced sepals of an Asteraceae floret that take the form of trichomes or scale attached to the ovary or seed. 

  • The first hair on the chin. 

tussock

noun
  • A tuft or clump of green grass or similar verdure, forming a small hillock. 

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