arrow-grass family vs family Scheuchzeriaceae

arrow-grass family and family Scheuchzeriaceae both are nouns.

Word	Noun	Adjective	Verb	Adverb
arrow-grass family	Yes	No	No	No
family Scheuchzeriaceae	Yes	No	No	No

As nouns, arrow-grass family and family Scheuchzeriaceae are synonyms defined as:

arrow-grass family and family Scheuchzeriaceae: a family of monocotyledonous bog herbs of order Naiadales

Other synonyms of arrow-grass family include family Juncaginaceae, Juncaginaceae, Scheuchzeriaceae.

arrow-grass family (noun)	family Scheuchzeriaceae (noun)
a family of monocotyledonous bog herbs of order Naiadales	a family of monocotyledonous bog herbs of order Naiadales