yellow water flag vs yellow iris

yellow water flag and yellow iris both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellow water flag	Yes	No	No	No
yellow iris	Yes	No	No	No

As nouns, yellow water flag and yellow iris are synonyms defined as:

yellow water flag and yellow iris: common yellow-flowered iris of Europe and North Africa, naturalized in United States and often cultivated

Other synonyms of yellow water flag include Iris pseudacorus, yellow flag.

yellow water flag (noun)	yellow iris (noun)
common yellow-flowered iris of Europe and North Africa, naturalized in United States and often cultivated	common yellow-flowered iris of Europe and North Africa, naturalized in United States and often cultivated