Rheum emodi vs rhubarb plant

Rheum emodi and rhubarb plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rheum emodi	Yes	No	No	No
rhubarb plant	Yes	No	No	No

As nouns, rhubarb plant is a hypernym of Rheum emodi; that is, rhubarb plant is a word with a broader meaning than Rheum emodi:

Rheum emodi: Asian herb (Himalayas)
rhubarb plant: plants having long green or reddish acidic leafstalks growing in basal clumps; stems (and only the stems) are edible when cooked; leaves are poisonous

Other hypernyms of Rheum emodi include rhubarb.

Rheum emodi (noun)	rhubarb plant (noun)
Asian herb (Himalayas)	plants having long green or reddish acidic leafstalks growing in basal clumps; stems (and only the stems) are edible when cooked; leaves are poisonous