Halesia carolina vs silver bell

Halesia carolina and silver bell both are nouns.

Word	Noun	Adjective	Verb	Adverb
Halesia carolina	Yes	No	No	No
silver bell	Yes	No	No	No

As nouns, silver bell is a hypernym of Halesia carolina; that is, silver bell is a word with a broader meaning than Halesia carolina:

Halesia carolina: medium-sized tree of West Virginia to Florida and Texas
silver bell: any of various deciduous trees of the genus Halesia having white bell-shaped flowers

Halesia carolina (noun)	silver bell (noun)
medium-sized tree of West Virginia to Florida and Texas	any of various deciduous trees of the genus Halesia having white bell-shaped flowers