Alnus rubra vs red alder

Alnus rubra and red alder both are nouns.

Word	Noun	Adjective	Verb	Adverb
Alnus rubra	Yes	No	No	No
red alder	Yes	No	No	No

As nouns, Alnus rubra and red alder are synonyms defined as:

Alnus rubra and red alder: large tree of Pacific coast of North America having hard red wood much used for furniture

Other synonyms of Alnus rubra include Oregon alder.

Alnus rubra (noun)	red alder (noun)
large tree of Pacific coast of North America having hard red wood much used for furniture	large tree of Pacific coast of North America having hard red wood much used for furniture