mountain alder vs Acer spicatum

mountain alder and Acer spicatum both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain alder	Yes	No	No	No
Acer spicatum	Yes	No	No	No

As nouns, mountain alder and Acer spicatum are synonyms defined as:

mountain alder and Acer spicatum: small shrubby maple of eastern North America; scarlet in autumn

Other synonyms of mountain alder include mountain maple.

mountain alder (noun)	Acer spicatum (noun)
small shrubby maple of eastern North America; scarlet in autumn	small shrubby maple of eastern North America; scarlet in autumn
tree of western United States