little clubmoss vs club moss

little clubmoss and club moss both are nouns.

Word	Noun	Adjective	Verb	Adverb
little clubmoss	Yes	No	No	No
club moss	Yes	No	No	No

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

little clubmoss: of northern Europe and America; resembling a miniature fir
club moss: primitive evergreen moss-like plant with spores in club-shaped strobiles

Other hypernyms of little clubmoss include club-moss, lycopod.

little clubmoss (noun)	club moss (noun)
of northern Europe and America; resembling a miniature fir	primitive evergreen moss-like plant with spores in club-shaped strobiles