Pickeringia montana vs shrub

Pickeringia montana and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Pickeringia montana	Yes	No	No	No
shrub	Yes	No	No	No

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

Pickeringia montana: spiny evergreen xerophytic shrub having showy rose and purple flowers and forming dense thickets; of dry rocky mountain slopes of California
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Pickeringia montana include bush.

Pickeringia montana (noun)	shrub (noun)
spiny evergreen xerophytic shrub having showy rose and purple flowers and forming dense thickets; of dry rocky mountain slopes of California	a low woody perennial plant usually having several major stems