/ Thesaurus / H Synonyms of helianthus angustifolius Find synonyms for: Noun1. swamp sunflower, Helianthus angustifolius, sunflower, helianthususage: sunflower of eastern North America having narrow leaves and found in bogsWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: rustic Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language