manroot vs scammonyroot

manroot

noun

  • A flowering plant in the gourd family (Cucurbitaceae), genus Marah, native to western North America. 

  • Ipomoea leptophylla 

  • Ipomoea pandurata 

scammonyroot

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