common valerian vs valerian

common valerian and valerian both are nouns.

Word	Noun	Adjective	Verb	Adverb
common valerian	Yes	No	No	No
valerian	Yes	No	No	No

As nouns, valerian is a hypernym of common valerian; that is, valerian is a word with a broader meaning than common valerian:

common valerian: tall rhizomatous plant having very fragrant flowers and rhizomes used medicinally
valerian: a plant of the genus Valeriana having lobed or dissected leaves and cymose white or pink flowers

common valerian (noun)	valerian (noun)
tall rhizomatous plant having very fragrant flowers and rhizomes used medicinally	a plant of the genus Valeriana having lobed or dissected leaves and cymose white or pink flowers