Veronica americana vs bog plant

Veronica americana and bog plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
Veronica americana	Yes	No	No	No
bog plant	Yes	No	No	No

As nouns, bog plant is a hypernym of Veronica americana; that is, bog plant is a word with a broader meaning than Veronica americana:

Veronica americana: plant of western North America and northeastern Asia having prostrate stems with dense racemes of pale violet to lilac flowers
bog plant: a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath

Other hypernyms of Veronica americana include marsh plant, swamp plant.

Veronica americana (noun)	bog plant (noun)
plant of western North America and northeastern Asia having prostrate stems with dense racemes of pale violet to lilac flowers	a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath