Mahonia nervosa vs shrub

Mahonia nervosa and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mahonia nervosa	Yes	No	No	No
shrub	Yes	No	No	No

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

Mahonia nervosa: small shrub with grey-green leaves and yellow flowers followed by glaucous blue berries
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of Mahonia nervosa include bush.

Mahonia nervosa (noun)	shrub (noun)
small shrub with grey-green leaves and yellow flowers followed by glaucous blue berries	a low woody perennial plant usually having several major stems