arbuscle vs seedling

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). 

seedling

noun
  • a tree smaller than a sapling. 

  • one grown in a nursery for transplanting. 

  • A young plant grown from seed. 

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