four-o'clock family vs genus Nyctaginia

four-o'clock family and genus Nyctaginia both are nouns.

Word	Noun	Adjective	Verb	Adverb
four-o'clock family	Yes	No	No	No
genus Nyctaginia	Yes	No	No	No

four-o'clock family (noun)	genus Nyctaginia (noun)
a family of flowering plants of the order Caryophyllales	a caryophyllaceous genus of the family Nyctaginaceae having only one species