papilla vs plumule

papilla

noun
  • A small fleshy projection on a plant. 

  • Any of the small protuberances on the upper surface of the tongue often containing taste buds. 

  • A vascular process of connective tissue extending into and nourishing the root of a hair, feather, or developing tooth. 

  • Any of the vascular protuberances of the dermal layer of the skin extending into the epidermal layer and often containing tactile corpuscles. 

plumule

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

  • One of the featherlike scales of certain male butterflies. 

  • The aftershaft of a feather. 

  • A down feather. 

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