parnassia vs bog star

parnassia and bog star both are nouns.

Word	Noun	Adjective	Verb	Adverb
parnassia	Yes	No	No	No
bog star	Yes	No	No	No

As nouns, bog star is a hyponym of parnassia; that is, bog star is a word with a more specific, narrower meaning than parnassia:

parnassia: any of various usually evergreen bog plants of the genus Parnassia having broad smooth basal leaves and a single pale flower resembling a buttercup
bog star: plant having ovate leaves in a basal rosette and white starlike flowers netted with green

Other hyponyms of parnassia include Parnassia palustris.

parnassia (noun)	bog star (noun)
any of various usually evergreen bog plants of the genus Parnassia having broad smooth basal leaves and a single pale flower resembling a buttercup	plant having ovate leaves in a basal rosette and white starlike flowers netted with green