carpet grass vs smut grass

carpet grass and smut grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
carpet grass	Yes	No	No	No
smut grass	Yes	No	No	No

As nouns, carpet grass and smut grass are synonyms defined as:

carpet grass and smut grass: grass native to West Indies but common in southern United States having tufted wiry stems often infested with a dark fungus

Other synonyms of carpet grass include blackseed, Sporobolus poiretii.

carpet grass (noun)	smut grass (noun)
grass native to West Indies but common in southern United States having tufted wiry stems often infested with a dark fungus	grass native to West Indies but common in southern United States having tufted wiry stems often infested with a dark fungus