Salviniaceae vs fern family

Salviniaceae and fern family both are nouns.

Word	Noun	Adjective	Verb	Adverb
Salviniaceae	Yes	No	No	No
fern family	Yes	No	No	No

As nouns, fern family is a hypernym of Salviniaceae; that is, fern family is a word with a broader meaning than Salviniaceae:

Salviniaceae: a family of water ferns containing the two genera Azolla and Salvinia (Salviniaceae)
fern family: families of ferns and fern allies

Salviniaceae (noun)	fern family (noun)
a family of water ferns containing the two genera Azolla and Salvinia (Salviniaceae)	families of ferns and fern allies