pickerel weed vs hydrophyte

pickerel weed and hydrophyte both are nouns.

Word	Noun	Adjective	Verb	Adverb
pickerel weed	Yes	No	No	No
hydrophyte	Yes	No	No	No

As nouns, hydrophyte is a hypernym of pickerel weed; that is, hydrophyte is a word with a broader meaning than pickerel weed:

pickerel weed: American plant having spikes of blue flowers and growing in shallow water of streams and ponds
hydrophyte: 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 pickerel weed include aquatic plant, hydrophytic plant, water plant.

pickerel weed (noun)	hydrophyte (noun)
American plant having spikes of blue flowers and growing in shallow water of streams and ponds	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