Pinckneya pubens vs shrub

Pinckneya pubens and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pinckneya pubens	Yes	No	No	No
shrub	Yes	No	No	No

As nouns, shrub is a hypernym of Pinckneya pubens; that is, shrub is a word with a broader meaning than Pinckneya pubens:

Pinckneya pubens: ornamental shrub or small tree of swampy areas in southwestern United States having large pink or white sepals and yielding Georgia bark for treating fever
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Pinckneya pubens include bush.

Pinckneya pubens (noun)	shrub (noun)
ornamental shrub or small tree of swampy areas in southwestern United States having large pink or white sepals and yielding Georgia bark for treating fever	a low woody perennial plant usually having several major stems