arbuscle vs frutex

arbuscle

noun
  • A plant midway in height between a shrub and a tree; a dwarf tree. 

  • The site at which a symbiotic fungus attaches to the roots of a plant and exchanges nutrients, etc., with it. 

  • A branched hypha in some fungi. 

  • A clump of feather-like cilia (hairlike structures). 

frutex

noun
  • A plant with a woody, durable stem, but less than a tree; a shrub. 

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