carpet grass vs blackseed

carpet grass and blackseed both are nouns.

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

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

carpet grass and blackseed: 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 smut grass, Sporobolus poiretii.

carpet grass (noun)	blackseed (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