Rhode Island bent vs bent grass

Rhode Island bent and bent grass both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rhode Island bent	Yes	No	No	No
bent grass	Yes	No	No	No

As nouns, bent grass is a hypernym of Rhode Island bent; that is, bent grass is a word with a broader meaning than Rhode Island bent:

Rhode Island bent: common grass with slender stems and narrow leaves
bent grass: grass for pastures and lawns especially bowling and putting greens

Other hypernyms of Rhode Island bent include bent-grass, bent.

Rhode Island bent (noun)	bent grass (noun)
common grass with slender stems and narrow leaves	grass for pastures and lawns especially bowling and putting greens