rauvolfia vs shrub

rauvolfia and shrub both are nouns.

Word	Noun	Adjective	Verb	Adverb
rauvolfia	Yes	No	No	No
shrub	Yes	No	No	No

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

rauvolfia: any shrub or small tree of the genus Rauwolfia having leaves in whorls and cymose flowers; yield substances used medicinally especially as emetics or purgatives or antihypertensives
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of rauvolfia include bush.

rauvolfia (noun)	shrub (noun)
any shrub or small tree of the genus Rauwolfia having leaves in whorls and cymose flowers; yield substances used medicinally especially as emetics or purgatives or antihypertensives	a low woody perennial plant usually having several major stems