aquatic plant vs vascular plant

aquatic plant and vascular plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
aquatic plant	Yes	No	No	No
vascular plant	Yes	No	No	No

As nouns, vascular plant is a hypernym of aquatic plant; that is, vascular plant is a word with a broader meaning than aquatic plant:

aquatic 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
vascular plant: green plant having a vascular system: ferns, gymnosperms, angiosperms

Other hypernyms of aquatic plant include tracheophyte.

aquatic plant (noun)	vascular plant (noun)
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	green plant having a vascular system: ferns, gymnosperms, angiosperms