wood-fern vs fern

wood-fern and fern both are nouns.

Word	Noun	Adjective	Verb	Adverb
wood-fern	Yes	No	No	No
fern	Yes	No	No	No

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

wood-fern: any of various ferns of the genus Dryopteris
fern: any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores

wood-fern (noun)	fern (noun)
any of various ferns of the genus Dryopteris	any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores