Alisma plantago-aquatica is a hairless plant that grows in shallow water, consists of a fibrous root, several basal long stemmed leaves 15–30 cm long, and a triangular stem up to 1 m tall. It has branched inflorescence bearing numerous small flowers, 1 cm across, with three round or slightly jagged, white or pale purple petals. The flowers open in the afternoon. There are 3 blunt green sepals, and 6 stamens per flower. The carpels often exist as a flat single whorl. It flowers from June until August.The word alisma is said to be a word of Celtic origin meaning "water", a reference to the habitat in which it grows. Early botanists named it after the Plantago because of the similarity of their leaves.