genus Syringa vs Syringa

genus Syringa and Syringa both are nouns.

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

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

genus Syringa and Syringa: genus of Old World shrubs or low trees having fragrant flowers in showy panicles: lilacs

genus Syringa (noun)	Syringa (noun)
genus of Old World shrubs or low trees having fragrant flowers in showy panicles: lilacs	genus of Old World shrubs or low trees having fragrant flowers in showy panicles: lilacs