Pteridium vs fern genus

Pteridium and fern genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pteridium	Yes	No	No	No
fern genus	Yes	No	No	No

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

Pteridium (noun)	fern genus (noun)
a genus of ferns belonging to the family Dennstaedtiaceae	genera of ferns and fern allies