stipule vs stylet

stipule

noun
  • A basal appendage of a typical leaf of a flowering plant, usually appearing paired beside the petiole although sometimes absent or highly modified. 

stylet

noun
  • A style of a plant's flower. 

  • A slender medical probe or device. 

  • A stiff, slender organ of an animal. 

  • An engraving tool, a stylus. 

  • A poniard or stiletto. 

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