whitecup vs nierembergia

whitecup and nierembergia both are nouns.

Word	Noun	Adjective	Verb	Adverb
whitecup	Yes	No	No	No
nierembergia	Yes	No	No	No

As nouns, nierembergia is a hypernym of whitecup; that is, nierembergia is a word with a broader meaning than whitecup:

whitecup: prostrate woody South American herb with white tubular flowers often tinged with blue or rose
nierembergia: any of various plants of the genus Nierembergia having upturned bell-shaped flowers

Other hypernyms of whitecup include cupflower.

whitecup (noun)	nierembergia (noun)
prostrate woody South American herb with white tubular flowers often tinged with blue or rose	any of various plants of the genus Nierembergia having upturned bell-shaped flowers