Indian rhubarb vs Rheum australe

Indian rhubarb and Rheum australe both are nouns.

Word	Noun	Adjective	Verb	Adverb
Indian rhubarb	Yes	No	No	No
Rheum australe	Yes	No	No	No

As nouns, Indian rhubarb and Rheum australe are synonyms defined as:

Other synonyms of Indian rhubarb include Himalayan rhubarb, red-veined pie plant, Rheum emodi.

Indian rhubarb (noun)	Rheum australe (noun)
rhizomatous perennial herb with large dramatic peltate leaves and white to bright pink flowers in round heads on leafless stems; colonizes stream banks in the Sierra Nevada in California	Asian herb (Himalayas)
Asian herb (Himalayas)