bitterweed vs whitetop

bitterweed

noun
  • Artemisia tripartita subsp. tripartita (syn. Artemisia trifida; threetip sagebrush) 

  • The plant Helenium amarum (yellow sneezeweed). 

  • Any plant in the genus Ambrosia, especially Ambrosia artemisiifolia (common ragweed). 

  • Parthenium hysterophorus (false ragweed) 

  • Picris rhagadioloides (syn. Picris sprengeriana; tall oxtongue) 

  • Tetraneuris spp. 

whitetop

noun
  • Lepidium draba, a perennial herb that reproduces by seeds and by horizontal creeping roots. 

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