Zip vs stolon

Zip

noun
  • A Sicilian or Italian Mafioso who is relatively new to the United States. 

stolon

noun
  • A hypha that acts as a runner, connecting sporangiophores. 

  • A shoot that grows along the ground and produces roots at its nodes; a runner. 

  • A structure formed by some colonial organisms from which offspring are produced by budding, found in bryozoans, pterobranchs, some corals, and other invertebrates. 

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