calamus vs sweet flag

calamus and sweet flag both are nouns.

Word	Noun	Adjective	Verb	Adverb
calamus	Yes	No	No	No
sweet flag	Yes	No	No	No

As nouns, calamus and sweet flag are synonyms defined as:

calamus and sweet flag: perennial marsh plant having swordlike leaves and aromatic roots

Other synonyms of calamus include Acorus calamus, flagroot, myrtle flag, sweet calamus.

calamus (noun)	sweet flag (noun)
the hollow spine of a feather	perennial marsh plant having swordlike leaves and aromatic roots
any tropical Asian palm of the genus Calamus; light tough stems are a source of rattan canes
perennial marsh plant having swordlike leaves and aromatic roots
the aromatic root of the sweet flag used medicinally