grass family vs Festuca

grass family and Festuca both are nouns.

Word	Noun	Adjective	Verb	Adverb
grass family	Yes	No	No	No
Festuca	Yes	No	No	No

grass family (noun)	Festuca (noun)
the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane	a genus of tufted perennial grasses of the family Gramineae