Greek valerian vs Polemonium caeruleum

Greek valerian and Polemonium caeruleum both are nouns.

Word	Noun	Adjective	Verb	Adverb
Greek valerian	Yes	No	No	No
Polemonium caeruleum	Yes	No	No	No

As nouns, Greek valerian and Polemonium caeruleum are synonyms defined as:

Greek valerian and Polemonium caeruleum: pinnate-leaved European perennial having bright blue or white flowers

Greek valerian (noun)	Polemonium caeruleum (noun)
pinnate-leaved European perennial having bright blue or white flowers	pinnate-leaved European perennial having bright blue or white flowers
erect or spreading perennial of the eastern United States