swamp cottonwood vs swamp poplar

swamp cottonwood and swamp poplar both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamp cottonwood	Yes	No	No	No
swamp poplar	Yes	No	No	No

As nouns, swamp cottonwood and swamp poplar are synonyms defined as:

swamp cottonwood and swamp poplar: North American poplar with large rounded scalloped leaves and brownish bark and wood

Other synonyms of swamp cottonwood include black cottonwood, downy poplar, Populus heterophylla.

swamp cottonwood (noun)	swamp poplar (noun)
North American poplar with large rounded scalloped leaves and brownish bark and wood	North American poplar with large rounded scalloped leaves and brownish bark and wood