bloodroot vs potentilla

bloodroot

noun
  • A North American plant, Sanguinaria canadensis, of the poppy family, which has a red root and sap and a single white flower in early spring. 

potentilla

noun
  • Any of many shrubs and herbs of the genus Potentilla; the cinquefoils. 

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