blackseed vs hognut

blackseed

noun
  • A spice plant with aromatic black seeds, Nigella sativa 

hognut

noun
  • Bunium bulbocastanum (black cumin) of the Apiaceae. 

  • Conopodium majus, a tuberous plant of the Apiaceae. 

  • Certain rushpeas, particularly Hoffmannseggia glauca (syn. Hoffmannseggia densiflora) Indian rushpea, of the Fabaceae. 

  • The pignut or hickory (Carya glabra of family Juglandaceae). 

  • Hyptis suaveolens of the Lamiaceae. 

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