May lily vs liliaceous plant

May lily and liliaceous plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
May lily	Yes	No	No	No
liliaceous plant	Yes	No	No	No

As nouns, liliaceous plant is a hypernym of May lily; that is, liliaceous plant is a word with a broader meaning than May lily:

May lily: low-growing perennial plant having usually two large oblong lanceolate leaves and a raceme of small fragrant nodding bell-shaped flowers followed by scarlet berries
liliaceous plant: plant growing from a bulb or corm or rhizome or tuber

May lily (noun)	liliaceous plant (noun)
low-growing perennial plant having usually two large oblong lanceolate leaves and a raceme of small fragrant nodding bell-shaped flowers followed by scarlet berries	plant growing from a bulb or corm or rhizome or tuber