American centaury vs marsh pink

American centaury and marsh pink both are nouns.

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

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

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

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

American centaury (noun)	marsh pink (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