Sagittaria sagittifolia

The round tuber is edible. It is starchy with a bland flavour and a texture similar to a potato but somewhat crunchier, even when cooked. In Japan, it is known as kuwai クワイ (慈姑) and its tuber is eaten particularly during the New Year.^{[dubious – discuss]} In China, it is known as 慈姑 cígū and often used in winter hot pots.^[3] In Vietnam, the plant's young petiole leaves and rhizomes are used for soups.^{[6][dubious – discuss]}

Remnants of Sagittaria sagittifolia have been found in the Paleolithic/Mesolithic site of Całowanie in Poland.^[7]

S. sagittifolia is used in Chinese medicine,^{[citation needed]} and in 2006 seven new ent-rosane diterpenoids and a new labdane diterpene were purified from the plant. Four of these compounds (Sagittine A–D) exhibited antibacterial activity against Streptococcus mutans and Actinomyces naeslundii while another (Sagittine E) was only active against A. naeslundii (MIC = 62.5 μg ml–1). Recently, the same group identified five new diterpenoids from Sagittaria pygmaea. None displayed activity against A. actinomycetemcomitans, while four of the others were active against A. viscosus and three against S. mutans, of which 18-ß-D-3',6'-diacetoxyglucopyranosyl-ent-kaur-16-ene was the most active.^[8]

• Sorting Sagittaria names
• Photo of Sagittaria sagittifolia tubers