spikemoss vs club-moss

spikemoss and club-moss both are nouns.

Word	Noun	Adjective	Verb	Adverb
spikemoss	Yes	No	No	No
club-moss	Yes	No	No	No

As nouns, club-moss is a hypernym of spikemoss; that is, club-moss is a word with a broader meaning than spikemoss:

spikemoss: any of numerous fern allies of the genus Selaginella
club-moss: primitive evergreen moss-like plant with spores in club-shaped strobiles

Other hypernyms of spikemoss include club moss, lycopod.

spikemoss (noun)	club-moss (noun)
any of numerous fern allies of the genus Selaginella	primitive evergreen moss-like plant with spores in club-shaped strobiles