cuticle vs rhizodermis

cuticle

noun
  • A noncellular protective covering outside the epidermis of many invertebrates and plants. 

  • The strip of hardened skin at the base and sides of a fingernail or toenail. 

  • A thin skin formed on the surface of a liquid. 

  • The outermost layer of the skin of vertebrates; the epidermis. 

  • Dead or cornified epidermis. 

rhizodermis

noun
  • The outermost primary cell layer of the root. 

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