Alisma Plantago-aquatica

The Common Water-plantain (Alisma plantago-aquatica), also known as Mad-dog weed, is a perennial flowering plant native to most of the Northern Hemisphere, in Europe, northern Asia, and North America. It is found on mud or in fresh waters.

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.