grass family vs Arrhenatherum

grass family and Arrhenatherum both are nouns.

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

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