fleabane vs richweed

fleabane

noun
  • Pluchea spp. (camphorweeds) 

  • Pulicaria spp. (false fleabane), especially common fleabane (Pulicaria dysenterica subsp. dysenterica, formerly Inula dysenterica) 

  • Erigeron spp., especially Erigeron acre (blue fleabane) 

  • Inula spp. (yellowheads) 

  • Also, in subfamily Cichorioideae, Vernonia spp. (ironweeds). 

  • Conyza spp. (butterweeds or horseweed) 

  • mostly in two tribes of subfamily Asteroideae 

richweed

noun
  • Pilea pumila, a herb of the nettle family with a smooth, juicy, pellucid stem. 

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