aigrette vs plumule

aigrette

noun
  • A feather or plume, or feather-shaped item, used as an adornment or ornament. 

  • The lesser white heron. 

  • The feathery crown of some seeds (such as the dandelion). 

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. 

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