common birch vs Betula pendula

common birch and Betula pendula both are nouns.

Word	Noun	Adjective	Verb	Adverb
common birch	Yes	No	No	No
Betula pendula	Yes	No	No	No

As nouns, common birch and Betula pendula are synonyms defined as:

common birch and Betula pendula: European birch with silvery white peeling bark and markedly drooping branches

Other synonyms of common birch include European white birch, silver birch.

common birch (noun)	Betula pendula (noun)
European birch with silvery white peeling bark and markedly drooping branches	European birch with silvery white peeling bark and markedly drooping branches