ramulus vs withy

ramulus

noun
  • A small branch, or branchlet, of corals, hydroids, and similar organisms. 

withy

noun
  • The osier (Salix viminalis), a type of willow. 

  • A long flexible twig of the osier; a withe. 

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