boulder fern vs scented fern

boulder fern and scented fern both are nouns.

Word	Noun	Adjective	Verb	Adverb
boulder fern	Yes	No	No	No
scented fern	Yes	No	No	No

As nouns, boulder fern and scented fern are synonyms defined as:

boulder fern and scented fern: fern of eastern North America with pale green fronds and an aroma like hay

Other synonyms of boulder fern include Dennstaedtia punctilobula, hay-scented, hay-scented fern.

boulder fern (noun)	scented fern (noun)
fern of eastern North America with pale green fronds and an aroma like hay	fern of eastern North America with pale green fronds and an aroma like hay
	common perennial aromatic herb native to Eurasia having buttonlike yellow flower heads and bitter-tasting pinnate leaves sometimes used medicinally
	sweetly scented African fern with narrow bipinnate fronds