boxthorn vs toyon

boxthorn

noun
  • Any plant of the genus Lycium. 

toyon

noun
  • A chiefly Californian ornamental evergreen shrub (Photinia arbutifolia), syn. Heteromeles arbutifolia) of the rose family having white flowers succeeded by red berries. 

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