Beta vulgaris rubra vs beet

Beta vulgaris rubra and beet both are nouns.

Word	Noun	Adjective	Verb	Adverb
Beta vulgaris rubra	Yes	No	No	No
beet	Yes	No	No	No

As nouns, beet is a hypernym of Beta vulgaris rubra; that is, beet is a word with a broader meaning than Beta vulgaris rubra:

Beta vulgaris rubra: beet having a massively swollen red root; widely grown for human consumption
beet: biennial Eurasian plant usually having a swollen edible root; widely cultivated as a food crop

Other hypernyms of Beta vulgaris rubra include Beta vulgaris, common beet.

Beta vulgaris rubra (noun)	beet (noun)
beet having a massively swollen red root; widely grown for human consumption	round red root vegetable
	biennial Eurasian plant usually having a swollen edible root; widely cultivated as a food crop