perigone vs wrapper

perigone

noun
  • perianth 

  • In mosses, the involucral bracts of a male flower. 

  • A sac surrounding the generative bodies in the gonophore of a hydroid. 

wrapper

noun
  • One who, or that which, wraps. 

  • An outer garment; a loose robe or dressing gown. 

  • Something that is wrapped around something else as a cover or protection: a wrapping. 

  • A construct, such as a class or module, that serves to mediate access to another. 

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