common polypody vs polypody

common polypody and polypody both are nouns.

Word	Noun	Adjective	Verb	Adverb
common polypody	Yes	No	No	No
polypody	Yes	No	No	No

As nouns, polypody is a hypernym of common polypody; that is, polypody is a word with a broader meaning than common polypody:

common polypody: mat-forming lithophytic or terrestrial fern with creeping rootstocks and large pinnatifid fronds found throughout North America and Europe and Africa and east Asia
polypody: any of numerous ferns of the genus Polypodium

common polypody (noun)	polypody (noun)
mat-forming lithophytic or terrestrial fern with creeping rootstocks and large pinnatifid fronds found throughout North America and Europe and Africa and east Asia	any of numerous ferns of the genus Polypodium