red alder vs Alnus rubra

red alder and Alnus rubra both are nouns.

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

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

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

Other synonyms of red alder include Oregon alder.

red alder (noun)	Alnus rubra (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