Lotus root
From Cookipedia
Lotus root is the root of nelumbo nucifera, the sacred lotus plant, also known as Indian lotus, bean of India, and sacred water-lily. This plant is an aquatic perennial, but if its seeds are preserved under favorable circumstances, they may remain viable for many years. Lotus seeds from this plant are also edible.
Lotus root is used as a vegetable in soups and braised dishes. It can be deep-fried and stir-fried and braised dishes. It can also be eaten raw, but there is a risk of parasite transmission (e.g. Fasciolopsis buski) so it is safer to cook them first.