derma vs rhizodermis

derma

noun
  • The inner layer of the skin. 

  • A Jewish dish of roast or boiled seasoned meat and flour etc. in a casing, especially kishke. 

rhizodermis

noun
  • The outermost primary cell layer of the root. 

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