mountain rice vs silkgrass

mountain rice and silkgrass both are nouns.

Word	Noun	Adjective	Verb	Adverb
mountain rice	Yes	No	No	No
silkgrass	Yes	No	No	No

As nouns, mountain rice and silkgrass are synonyms defined as:

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

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

mountain rice (noun)	silkgrass (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