Acorus calamus
Like the diploid strains of "Acorus calamus" in parts of the Himalayas, Mongolia, and C Siberia, the "Acorus americanus" diploid strain does not contain the procarcinogenic β-asarone. Research has consistently demonstrated that "β-asarone was not detectable in the North American spontaneous diploid "Acorus" ["Calamus var. Americanus"]".