Oxyria

a genus of plants of the Polygonaceae (buckwheat) family. They are perennial herbs with a creeping rhizome and radical kidney-shaped leaves on long petioles. The flowers are bisexual and in a panicle. The perianth is tetramerous; there are six stamens; the fruit is a pinnate nutlet. Two or three species are known in Eurasia and North America; they grow in the arctic zone and in the alpine belt of mountains, near brooks and springs, on shingle, and on rocky slopes. In the USSR mountain sorrel (O. digyna) grows in the tundra and mountains of Siberia and the Far East, while O. elatior grows in the Caucasus and Middle Asia. Oxyria leaves are acid to the taste and rich in vitamin C.