swamp willow vs black willow

swamp willow and black willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
swamp willow	Yes	No	No	No
black willow	Yes	No	No	No

As nouns, swamp willow and black willow are synonyms defined as:

swamp willow and black willow: North American shrubby willow having dark bark and linear leaves growing close to streams and lakes

Other synonyms of swamp willow include Salix nigra.

swamp willow (noun)	black willow (noun)
North American shrubby willow having dark bark and linear leaves growing close to streams and lakes	North American shrubby willow having dark bark and linear leaves growing close to streams and lakes