Three petal white flowers of Arrowhead

White flowers of Sagittaria sagittifolia, also called Arrowhead, due to the shape of its leaves. Family Alismataceae, native to wetlands in Europe and Asia. The flower has three white petals, and numerous purple stamens.
Photographed in Diemer Woods, Diemen, the Netherlands.
The round tuber is edible. It tastes bland, with a starchy texture, similar to a potato but somewhat crunchier, even when cooked. In Japan, it is known as Omodaka,オモダカ, 沢瀉, 澤瀉,面高, and its tuber is eaten particularly on the Chinese New Year. In China, it is known as 慈姑 cí gū and often used in winter hot pots. In Vietnam, the plant's young petiole leaves and rhizomes are used for soups.