red osier dogwood vs cornel

red osier dogwood and cornel both are nouns.

Word	Noun	Adjective	Verb	Adverb
red osier dogwood	Yes	No	No	No
cornel	Yes	No	No	No

As nouns, cornel is a hypernym of red osier dogwood; that is, cornel is a word with a broader meaning than red osier dogwood:

red osier dogwood: common North American shrub with reddish purple twigs and white flowers
cornel: a tree of shrub of the genus Cornus often having showy bracts resembling flowers

Other hypernyms of red osier dogwood include dogwood, dogwood tree.

red osier dogwood (noun)	cornel (noun)
common North American shrub with reddish purple twigs and white flowers	a tree of shrub of the genus Cornus often having showy bracts resembling flowers