epidermis vs exocarp

epidermis

noun
  • The outer, protective layer of the skin of vertebrates, covering the dermis 

  • The similar outer layer of cells in invertebrates and plants 

exocarp

noun
  • The outermost layer of the pericarp of fruits; the skin or epicarp 

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