The yellow iris, progenitor of and 10 or so fine cultivars, is a common species in marshes, along river banks and water bodies and has water-purifying properties. Occur within Europe as well as in Siberia, the Caucasus, for Asia and N. America. They grow 1 m tall and have dark green, sword-shaped leaves 3 cm wide at the bases that die in autumn. Between them, branched flower stalks develop with many bright yellow flowers with black-brown veining.