meadow buttercup vs buttercup

meadow buttercup and buttercup both are nouns.

Word	Noun	Adjective	Verb	Adverb
meadow buttercup	Yes	No	No	No
buttercup	Yes	No	No	No

As nouns, buttercup is a hypernym of meadow buttercup; that is, buttercup is a word with a broader meaning than meadow buttercup:

meadow buttercup: perennial European buttercup with yellow spring flowers widely naturalized especially in eastern North America
buttercup: any of various plants of the genus Ranunculus

Other hypernyms of meadow buttercup include butter-flower, butterflower, crowfoot, goldcup, kingcup.

meadow buttercup (noun)	buttercup (noun)
perennial European buttercup with yellow spring flowers widely naturalized especially in eastern North America	any of various plants of the genus Ranunculus