pigweed vs portulaca

pigweed

noun
  • Portulaca bicolor, of Australia 

  • Polygonum aviculare (common knotgrass) 

  • Amaranthus species 

  • Heracleum sphondylium 

  • Any of various weedy plants sometimes used as pig fodder 

  • Chenopodium album, white goosefoot 

portulaca

noun
  • Any plant in the genus Portulaca 

  • Any of many tropical trailing herbs, of the genus Portulaca, having showy flowers 

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