marsh pink vs American centaury

marsh pink and American centaury both are nouns.

Word	Noun	Adjective	Verb	Adverb
marsh pink	Yes	No	No	No
American centaury	Yes	No	No	No

As nouns, marsh pink and American centaury are synonyms defined as:

marsh pink and American centaury: any of several pink-flowered marsh plant of the eastern United States resembling a true centaury

Other synonyms of marsh pink include bitter floom, rose pink, Sabbatia Angularis, Sabbatia stellaris.

marsh pink (noun)	American centaury (noun)
any of several pink-flowered marsh plant of the eastern United States resembling a true centaury	any of several pink-flowered marsh plant of the eastern United States resembling a true centaury