citrus vs genus Citrus

citrus and genus Citrus both are nouns.

Word	Noun	Adjective	Verb	Adverb
citrus	Yes	No	No	No
genus Citrus	Yes	No	No	No

citrus (noun)	genus Citrus (noun)
any of numerous fruits of the genus Citrus having thick rind and juicy pulp; grown in warm regions	orange, lemon, lime, etc.
any of numerous tropical usually thorny evergreen trees of the genus Citrus having leathery evergreen leaves and widely cultivated for their juicy edible fruits having leathery aromatic rinds