mountain rice vs Oryzopsis hymenoides

mountain rice and Oryzopsis hymenoides both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain rice	Yes	No	No	No
Oryzopsis hymenoides	Yes	No	No	No

As nouns, mountain rice and Oryzopsis hymenoides are synonyms defined as:

mountain rice and Oryzopsis hymenoides: valuable forage grass of dry upland areas and plains of western North America to northern Mexico

Other synonyms of mountain rice include Indian millet, silk grass, silkgrass.

mountain rice (noun)	Oryzopsis hymenoides (noun)
valuable forage grass of dry upland areas and plains of western North America to northern Mexico	valuable forage grass of dry upland areas and plains of western North America to northern Mexico