family Gramineae vs genus Agrostis

family Gramineae and genus Agrostis both are nouns.

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

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