water lily vs hydrophytic plant

water lily and hydrophytic plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
water lily	Yes	No	No	No
hydrophytic plant	Yes	No	No	No

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

water lily: an aquatic plant of the family Nymphaeaceae
hydrophytic plant: a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth

Other hypernyms of water lily include aquatic plant, hydrophyte, water plant.

water lily (noun)	hydrophytic plant (noun)
an aquatic plant of the family Nymphaeaceae	a plant that grows partly or wholly in water whether rooted in the mud, as a lotus, or floating without anchorage, as the water hyacinth