Ulmus rubra vs red elm

Ulmus rubra and red elm both are nouns.

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

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

Ulmus rubra and red elm: North American elm having rough leaves that are red when opening; yields a hard wood

Other synonyms of Ulmus rubra include slippery elm.

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