Nyssa aquatica vs tupelo

Nyssa aquatica and tupelo both are nouns.

Word	Noun	Adjective	Verb	Adverb
Nyssa aquatica	Yes	No	No	No
tupelo	Yes	No	No	No

As nouns, tupelo is a hypernym of Nyssa aquatica; that is, tupelo is a word with a broader meaning than Nyssa aquatica:

Nyssa aquatica: columnar swamp tree of southeastern to midwestern North America yielding pale soft easily worked wood
tupelo: any of several gum trees of swampy areas of North America

Other hypernyms of Nyssa aquatica include tupelo tree.

Nyssa aquatica (noun)	tupelo (noun)
columnar swamp tree of southeastern to midwestern North America yielding pale soft easily worked wood	any of several gum trees of swampy areas of North America
	pale soft wood of a tupelo tree especially the water gum