giant star grass vs Cynodon plectostachyum

giant star grass and Cynodon plectostachyum both are nouns.

Word	Noun	Adjective	Verb	Adverb
giant star grass	Yes	No	No	No
Cynodon plectostachyum	Yes	No	No	No

As nouns, giant star grass and Cynodon plectostachyum are synonyms defined as:

giant star grass and Cynodon plectostachyum: perennial grass having stems 3 to 4 feet high; used especially in Africa and India for pasture and hay

giant star grass (noun)	Cynodon plectostachyum (noun)
perennial grass having stems 3 to 4 feet high; used especially in Africa and India for pasture and hay	perennial grass having stems 3 to 4 feet high; used especially in Africa and India for pasture and hay