Brasenia schreberi, is a perennial aquatic plant of the same family as the water lily. Its young shoots are enveloped in a clear, jelly-like substance and are prized as food in Japan.
Junsai grows wild in ancient ponds with a thick layer of silt at the bottom. Mizorogaike in Kyoto (the name means ‘deep-mud pond’) is said to produce the best junsai in Japan. If junsai is transplanted artificially, the shoots will be bereft of the gelatinous covering and lose their culinary value.
Junsai is a summer food, available from May to August. It is first blanched and used for aemono or sunomono; see japanese culinary terms. It is also put into soup.