Athyrium pycnocarpon vs fern

Athyrium pycnocarpon and fern both are nouns.

Word	Noun	Adjective	Verb	Adverb
Athyrium pycnocarpon	Yes	No	No	No
fern	Yes	No	No	No

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

Athyrium pycnocarpon: North American fern with narrow fronds on yellowish leafstalks
fern: any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores

Athyrium pycnocarpon (noun)	fern (noun)
North American fern with narrow fronds on yellowish leafstalks	any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores