lesser spearwort vs bog plant

lesser spearwort and bog plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
lesser spearwort	Yes	No	No	No
bog plant	Yes	No	No	No

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

lesser spearwort: semiaquatic Eurasian perennial crowfoot with leaves shaped like spears; naturalized in New Zealand
bog plant: a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath

Other hypernyms of lesser spearwort include marsh plant, swamp plant.

lesser spearwort (noun)	bog plant (noun)
semiaquatic Eurasian perennial crowfoot with leaves shaped like spears; naturalized in New Zealand	a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath