swallow-wort vs tetterwort

swallow-wort

noun
  • The greater celandine / tetterwort, Chelidonium majus or Sanguinaria canadensis. 

  • Any of various plants of the genus Asclepias. 

  • The plant Euphorbia maculata (spotted spurge). 

  • Any of several vines of genus Vincetoxicum (syn. Cynanchum), especially black swallow-wort (Vincetoxicum nigrum, syn. Cynanchum nigrum) or white swallowwort (Vincetoxicum hirundinaria, syn. Cynanchum vincetoxicum) 

  • Seutera angustifolia 

  • Calotropis gen. et spp. 

tetterwort

noun
  • A plant used as a remedy for tetter, Chelidonium majus 

  • Sanguinaria canadensis, the bloodroot. 

How often have the words swallow-wort and tetterwort occurred in a corpus of books? (source: Google Ngram Viewer )