This time of year yellow flag is in flower and looking resplendent with its bright yellow flowers.
Iris, the mythological Greek messenger, who came to the earth via a rainbow, gives our wild iris - yellow flag - its scientific name - Iris pseudacorus.
Yellow flag is easily identified when in flower by its rich yellow flowers, which are similar to the garden iris so popular as border plants. There are three outer petals (sometimes called falls); three erect inner petals (standards); and three large stigmas. The leaves are long, sword shaped and flat.
They occur in large numbers by fresh water and in marshes. The flowering time is June-August. They occur throughout the British Isles.
Some, with many an anxious pain,
Childish wishes pursue,
From the pondhead gazed in vain
On the flag-flower's yellow hue;
Smiling o'er its shadow'd bloom,
While the flood's triumphing care
Crimpled round its guarded home. ("Recollections after a Ramble". J Clare).
The name, flag, is from Middle English "flagge", sword, referring to the sword-shaped leaves. These leaves can be between 60-120cm long and 2cm across, sharp-edged and pointed.
When you do come across yellow flag think of the poem above which well describes the yellow flowers smiling and gazing out from their guarded pondhead home.
Other names given to yellow flag include Jacob's sword, fliggers, daggers and fleur de lys. The later is reference to the role taken by iris in heraldry. The "fleur-de-lis, heraldic lily, has long been associated with the royal arms of France. Even today, it is popular with heraldic designs.