genus Arrhenatherum vs Poaceae

genus Arrhenatherum and Poaceae both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Arrhenatherum	Yes	No	No	No
Poaceae	Yes	No	No	No

genus Arrhenatherum (noun)	Poaceae (noun)
oat grass	the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane