Decumaria barbara vs hydrangea

Decumaria barbara and hydrangea both are nouns.

Word	Noun	Adjective	Verb	Adverb
Decumaria barbara	Yes	No	No	No
hydrangea	Yes	No	No	No

As nouns, hydrangea is a hypernym of Decumaria barbara; that is, hydrangea is a word with a broader meaning than Decumaria barbara:

Decumaria barbara: woody climber of southeastern United States having white flowers in compound terminal clusters
hydrangea: any of various deciduous or evergreen shrubs of the genus Hydrangea

Decumaria barbara (noun)	hydrangea (noun)
woody climber of southeastern United States having white flowers in compound terminal clusters	any of various deciduous or evergreen shrubs of the genus Hydrangea