eelgrass vs hydrophytic plant

eelgrass and hydrophytic plant both are nouns.

Word	Noun	Adjective	Verb	Adverb
eelgrass	Yes	No	No	No
hydrophytic plant	Yes	No	No	No

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

eelgrass: submerged marine plant with very long narrow leaves found in abundance along North Atlantic coasts
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 eelgrass include aquatic plant, hydrophyte, water plant.

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

eelgrass: submerged aquatic plant with ribbonlike leaves; Old World and Australia
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 eelgrass include aquatic plant, hydrophyte, water plant.

eelgrass (noun)	hydrophytic plant (noun)
submerged marine plant with very long narrow leaves found in abundance along North Atlantic coasts	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
submerged aquatic plant with ribbonlike leaves; Old World and Australia