genus Betula vs Betula

genus Betula and Betula both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Betula	Yes	No	No	No
Betula	Yes	No	No	No

As nouns, genus Betula and Betula are synonyms defined as:

genus Betula and Betula: a genus of trees of the family Betulaceae (such as birches)

genus Betula (noun)	Betula (noun)
a genus of trees of the family Betulaceae (such as birches)	a genus of trees of the family Betulaceae (such as birches)