Prunus cerasifera vs plum tree

Prunus cerasifera and plum tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Prunus cerasifera	Yes	No	No	No
plum tree	Yes	No	No	No

As nouns, plum tree is a hypernym of Prunus cerasifera; that is, plum tree is a word with a broader meaning than Prunus cerasifera:

Prunus cerasifera: small Asiatic tree bearing edible red or yellow fruit
plum tree: any of several trees producing edible oval fruit having a smooth skin and a single hard stone

Other hypernyms of Prunus cerasifera include plum.

Prunus cerasifera (noun)	plum tree (noun)
small Asiatic tree bearing edible red or yellow fruit	any of several trees producing edible oval fruit having a smooth skin and a single hard stone