grass family vs Digitaria

grass family and Digitaria both are nouns.

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

grass family (noun)	Digitaria (noun)
the grasses: chiefly herbaceous but some woody plants including cereals, bamboo, reeds, sugar cane	crab grass; finger grass