Ophioglossum vs adder's tongue

Ophioglossum and adder's tongue both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ophioglossum	Yes	No	No	No
adder's tongue	Yes	No	No	No

Ophioglossum (noun)	adder's tongue (noun)
the type genus of the fern family Ophioglossaceae	ferns with fertile spikes shaped like a snake's tongue