puka vs shrub

puka and shrub both are nouns.

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

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

puka: South American shrub or small tree having long shining evergreen leaves and panicles of green or yellow flowers
shrub: a low woody perennial plant usually having several major stems

Other hypernyms of puka include bush.

puka (noun)	shrub (noun)
small roundheaded New Zealand tree having large resinous leaves and panicles of green-white flowers	a low woody perennial plant usually having several major stems
South American shrub or small tree having long shining evergreen leaves and panicles of green or yellow flowers