Cornus florida vs dogwood tree

Cornus florida and dogwood tree both are nouns.

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

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

Cornus florida: deciduous tree; celebrated for its large white or pink bracts and stunning autumn color that is followed by red berries
dogwood tree: a tree of shrub of the genus Cornus often having showy bracts resembling flowers

Other hypernyms of Cornus florida include cornel, dogwood.

Cornus florida (noun)	dogwood tree (noun)
deciduous tree; celebrated for its large white or pink bracts and stunning autumn color that is followed by red berries	a tree of shrub of the genus Cornus often having showy bracts resembling flowers