yellow-eyed grass vs bog plant

yellow-eyed grass and bog plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
yellow-eyed grass	Yes	No	No	No
bog plant	Yes	No	No	No

As nouns, bog plant is a hypernym of yellow-eyed grass; that is, bog plant is a word with a broader meaning than yellow-eyed grass:

yellow-eyed grass: any of several rushlike plants, especially of the pine barrens of southern United States
bog plant: a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath

Other hypernyms of yellow-eyed grass include marsh plant, swamp plant.

yellow-eyed grass (noun)	bog plant (noun)
any of several rushlike plants, especially of the pine barrens of southern United States	a semiaquatic plant that grows in soft wet land; most are monocots: sedge, sphagnum, grasses, cattails, etc; possibly heath