Brazilian potato tree vs shrub

Brazilian potato tree and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Brazilian potato tree	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of Brazilian potato tree; that is, shrub is a word with a broader meaning than Brazilian potato tree:

Brazilian potato tree: South American shrub or small tree widely cultivated in the tropics; not a true potato
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Brazilian potato tree include bush.

Brazilian potato tree (noun)	shrub (noun)
South American shrub or small tree widely cultivated in the tropics; not a true potato	a low woody perennial plant usually having several major stems