bog laurel vs kalmia

bog laurel and kalmia both are nouns.

Word	Noun	Adjective	Verb	Adverb
bog laurel	Yes	No	No	No
kalmia	Yes	No	No	No

As nouns, kalmia is a hypernym of bog laurel; that is, kalmia is a word with a broader meaning than bog laurel:

bog laurel: laurel of bogs of northwestern United States having small purple flowers and pale leaves that are glaucous beneath
kalmia: any plant of the genus Kalmia

bog laurel (noun)	kalmia (noun)
laurel of bogs of northwestern United States having small purple flowers and pale leaves that are glaucous beneath	any plant of the genus Kalmia