sour-gum family vs family Nyssaceae

sour-gum family and family Nyssaceae both are nouns.

Word	Noun	Adjective	Verb	Adverb
sour-gum family	Yes	No	No	No
family Nyssaceae	Yes	No	No	No

As nouns, sour-gum family and family Nyssaceae are synonyms defined as:

sour-gum family and family Nyssaceae: a family of dicotyledonous trees of order Myrtales that includes the sour gum trees

Other synonyms of sour-gum family include Nyssaceae, tupelo family.

sour-gum family (noun)	family Nyssaceae (noun)
a family of dicotyledonous trees of order Myrtales that includes the sour gum trees	a family of dicotyledonous trees of order Myrtales that includes the sour gum trees