selfheal vs sugar palm

selfheal

noun
  • Especially, Prunella vulgaris. 

  • A small, herbaceous European plant with blue-violet flowers from any species of genus Prunella. 

sugar palm

noun
  • especially, Arenga pinnata 

  • Borassus flabellifer (palmyra palms) 

  • Cocos nucifera (coconut palm) 

  • Any of various palm species used to produce sugar, including 

  • Caryota urens (fishtail palm, sago palm, toddy palm, wine palm) 

  • Phoenix spp. (date palm) 

  • Corypha elata (buri palm, gebang palm) 

  • Nypa fruticans (nipa palm) 

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