plumule vs remex

plumule

noun
  • The aftershaft of a feather. 

  • One of the featherlike scales of certain male butterflies. 

  • The first bud, or growing point, of a plant embryo, situated above the cotyledons. 

  • A down feather. 

remex

noun
  • The flight feather of a bird. 

  • A quill. 

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