hart's-tongue vs fern

hart's-tongue and fern both are nouns.

Word	Noun	Adjective	Verb	Adverb
hart's-tongue	Yes	No	No	No
fern	Yes	No	No	No

As nouns, fern is a hypernym of hart's-tongue; that is, fern is a word with a broader meaning than hart's-tongue:

hart's-tongue: Eurasian fern with simple lanceolate fronds
fern: any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores

As nouns, fern is a hypernym of hart's-tongue; that is, fern is a word with a broader meaning than hart's-tongue:

hart's-tongue: tropical American terrestrial fern with leathery lanceolate fronds; sometimes placed in genus Polybotrya
fern: any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores

hart's-tongue (noun)	fern (noun)
Eurasian fern with simple lanceolate fronds	any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores
tropical American terrestrial fern with leathery lanceolate fronds; sometimes placed in genus Polybotrya