what is calamus
Acorus calamus (also called Sweet Flag or Calamus, among many common names) is a tall perennial wetland monocot of the Acoraceae family, in the genus Acorus.In spite of common names that include the words  rush  and  sedge , it is neither a rush nor sedge.. calamus and products derived from A. calamus (such as its oil) were banned from use as human food or as a food additive in 1968 by the United States Food and Drug Administration.