Yellow Iris (or Yellow Flag) - Iris pseudacorus
The large, golden-yellow flower of the Yellow Iris are one of the most brilliant and frequent splashes of colour in fresh water wetlands.
The greenish-grey leaves grow from the base of the plant, in a sort of narrow fan; the leaves are ribbon-shaped and flat but quite thick in the middle, giving them an elongated diamond shape in section and making them firm and strong.
The flowers appear from April to July, supported by a flowering stem that grows a metre high. On closer examination, it can be seen that the large outer tepals are not completely yellow, but bear a delicate violet-brown lattice.
All the parts of the flower, ovaries and stamens collaborate in forming the "flag" to attract pollinating insects.
The plant is perennial and has an blackish, elongated branching rhizome which produces young shoots every year. Herbalists used the juice from the rhizome to treat wounds externally. In times of famine, the seeds of the Yellow Flag were sometimes used as a substitute for coffee.
Recently it has been verified that the plant is capable of absorbing heavy metals occurring in polluted water in its rhizome.
