Marsh plant having clusters of small white or pinkish flowers and broad pointed or rounded leaves WordNet 3.0 & Open English WordNet

Alisma plantago-aquatica, also known as European water-plantain, common water-plantain or mad-dog weed, is a perennial flowering aquatic plant widespread across most of Europe and Asia, and apparently spread elsewhere in both the Old and New World. Wikipedia

Species of plant Wikidata

Any of several plants, of the genus Alisma, that inhabit marshy places. Wiktionary

Alisma. Wiktionary (translation)