black poplar vs poplar

black poplar and poplar both are nouns.

Word	Noun	Adjective	Verb	Adverb
black poplar	Yes	No	No	No
poplar	Yes	No	No	No

As nouns, poplar is a hypernym of black poplar; that is, poplar is a word with a broader meaning than black poplar:

black poplar: large European poplar
poplar: any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins

Other hypernyms of black poplar include poplar tree.

black poplar (noun)	poplar (noun)
large European poplar	any of numerous trees of north temperate regions having light soft wood and flowers borne in catkins
	soft light-colored non-durable wood of the poplar