bearbind vs convolvulus

bearbind

noun
  • European bindweed, lesser bindweed (Convolvulus arvensis). 

  • Hedge bindweed (Calystegia sepium) 

convolvulus

noun
  • Any of several plants, of the genus Convolvulus, found in temperate climates, having small trumpet-shaped flowers. 

  • A species of hawkmoth, Agrius convolvuli. 

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