sweet flag vs myrtle flag

sweet flag and myrtle flag both are nouns.

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

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

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

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

sweet flag (noun)	myrtle flag (noun)
perennial marsh plant having swordlike leaves and aromatic roots	perennial marsh plant having swordlike leaves and aromatic roots