lamb's quarters vs verdolaga

lamb's quarters

noun
  • Any of several similar plants of genera Chenopodium and Atriplex. 

  • Chenopodium album, of the goosefoot family, sometimes used as a potherb 

verdolaga

noun
  • Portulaca oleracea, common purslane. 

How often have the words lamb's quarters and verdolaga occurred in a corpus of books? (source: Google Ngram Viewer )