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