common myrtle vs Myrtus communis

common myrtle and Myrtus communis both are nouns.

Word	Noun	Adjective	Verb	Adverb
common myrtle	Yes	No	No	No
Myrtus communis	Yes	No	No	No

As nouns, common myrtle and Myrtus communis are synonyms defined as:

common myrtle and Myrtus communis: European shrub with white or rosy flowers followed by black berries

common myrtle (noun)	Myrtus communis (noun)
European shrub with white or rosy flowers followed by black berries	European shrub with white or rosy flowers followed by black berries