common bean vs yardlong bean

common bean

noun
  • A bean of such a plant, varying in size, shape and especially color. 

  • An herbaceous annual plant (Phaseolus vulgaris), grown for its edible bean. 

yardlong bean

noun
  • A vigorous climbing annual vine (Vigna unguiculata subsp. sesquipedalis) grown primarily for its strikingly long (35-75 cm) immature pods with uses very similar to that of a green bean. 

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