Cornus amomum vs dogwood tree

Cornus amomum and dogwood tree both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cornus amomum	Yes	No	No	No
dogwood tree	Yes	No	No	No

As nouns, dogwood tree is a hypernym of Cornus amomum; that is, dogwood tree is a word with a broader meaning than Cornus amomum:

Cornus amomum: shrub of eastern North America having purplish stems and blue fruit
dogwood tree: a tree of shrub of the genus Cornus often having showy bracts resembling flowers

Other hypernyms of Cornus amomum include cornel, dogwood.

Cornus amomum (noun)	dogwood tree (noun)
shrub of eastern North America having purplish stems and blue fruit	a tree of shrub of the genus Cornus often having showy bracts resembling flowers