pipewort vs hydrophytic plant

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

• pipewort: aquatic perennial of North America and Ireland and Hebrides having translucent green leaves in a basal spiral and dense buttonlike racemes of minute white flowers
• 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