Salix nigra vs swamp willow

Salix nigra and swamp willow both are nouns.

Word	Noun	Adjective	Verb	Adverb
Salix nigra	Yes	No	No	No
swamp willow	Yes	No	No	No

As nouns, Salix nigra and swamp willow are synonyms defined as:

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

Other synonyms of Salix nigra include black willow.

Salix nigra (noun)	swamp 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