red elm vs Ulmus serotina

red elm and Ulmus serotina both are nouns.

Word	Noun	Adjective	Verb	Adverb
red elm	Yes	No	No	No
Ulmus serotina	Yes	No	No	No

As nouns, red elm and Ulmus serotina are synonyms defined as:

red elm and Ulmus serotina: autumn-flowering elm of southeastern United States

Other synonyms of red elm include September elm.

red elm (noun)	Ulmus serotina (noun)
North American elm having rough leaves that are red when opening; yields a hard wood	autumn-flowering elm of southeastern United States
autumn-flowering elm of southeastern United States