Corylus cornuta vs hazelnut

Corylus cornuta and hazelnut both are nouns.

Word	Noun	Adjective	Verb	Adverb
Corylus cornuta	Yes	No	No	No
hazelnut	Yes	No	No	No

As nouns, hazelnut is a hypernym of Corylus cornuta; that is, hazelnut is a word with a broader meaning than Corylus cornuta:

Corylus cornuta: hazel of western United States with conspicuous beaklike involucres on the nuts
hazelnut: any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk

Other hypernyms of Corylus cornuta include hazel, hazelnut tree.

Corylus cornuta (noun)	hazelnut (noun)
hazel of western United States with conspicuous beaklike involucres on the nuts	nut of any of several trees of the genus Corylus
	any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk