moonflower vs morning glory

moonflower and morning glory both are nouns.

Word	Noun	Adjective	Verb	Adverb
moonflower	Yes	No	No	No
morning glory	Yes	No	No	No

As nouns, morning glory is a hypernym of moonflower; that is, morning glory is a word with a broader meaning than moonflower:

moonflower: pantropical climber having white fragrant nocturnal flowers
morning glory: any of various twining vines having funnel-shaped flowers that close late in the day

moonflower (noun)	morning glory (noun)
pantropical climber having white fragrant nocturnal flowers	any of various twining vines having funnel-shaped flowers that close late in the day