genus Agrostis vs family Gramineae

genus Agrostis and family Gramineae both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Agrostis	Yes	No	No	No
family Gramineae	Yes	No	No	No

genus Agrostis (noun)	family Gramineae (noun)
annual or perennial grasses cosmopolitan in Northern Hemisphere: bent grass (so named from `bent' meaning an area of unfenced grassland)	the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane