Binomial name: Sagittaria sagittifolia
Sagittaria sagittifolia is native to wetlands throughout the temperate regions of Europe and Asia.
It is a herbaceous perennial plant, growing in water from 10–50cm deep. The leaves above water are arrowhead-shaped, the leaf blade 15–25cm long and 10–22 cm broad, on a long petiole holding the leaf up to 45 cm above water level. The plant also has narrow linear submerged leaves, up to 80 cm long and 2 cm broad. The flowers are 2-2.5cm broad, with three small sepals and three white petals, and numerous purple stamens.
The round tuber is edible. In China, it is known as Cigu, and its tuber is eaten particularly for Chinese New Year. It tastes bland, with a starchy texture, similar to a potato but somewhat crunchier, even when cooked.