YELLOW IRIS

YELLOW FLAG

Iris pseudacorus

Iris Family [Iridaceae]  

month8jun month8june month8jul month8july month8Aug

status
statusZnative
 
flower
flower8yellow
 
morph
morph8actino
 
petals
petalsZ3
3+3+'3'
stem
stem8lens
 
toxicity
toxicityZlowish
 

30th May 2007, Lancaster Canal, Galgate, Lancashire. Photo: © RWD
Always grows in shallow water such as canal sides and on slow-flowing freshwater streams, or on marshes.


1st June 2014, Blackleach resr, Walkden, Gtr M/cr Photo: © RWD
Grows 0.8 to 1.5m tall, these specimens at the taller end of the range.


30th May 2009, old dune slacks, Southport, Sefton Coast. Photo: © RWD
Leaves very long and linear, similar to those of Montbretia, Great Reedmace and Branched Bur-Reed here growing in damp ground where water collects over winter.


30th May 2009, old dune slacks, Southport, Sefton Coast. Photo: © RWD
Short wide leaves sheath of the stem at intervals, especially where the stem branches.


1st June 2014, MB&BC canal, Ringley, Gtr M/cr. Photo: © RWD
New flower-buds yet to open are spiked a little like Yellow-wort (Blackstonia perfoliata) but much taller.


1st June 2014, MB&BC canal, Ringley, Gtr M/cr. Photo: © RWD
The six petals are tightly wrapped up, the three outer are tepals, the as-yet unseen three inner are petals.


30th May 2007, Lancaster Canal, Galgate, Photo: © RWD
The tepals are larger than the petals and droop downwards.


30th May 2007, Lancaster Canal, Galgate, Photo: © RWD
Showing the outer tepals which hang down and the inner petals.


2nd May 2007, Leeds & Liverpool Canal, Aintree. Photo: © RWD
The outer tepals have reddish lines marked upon the upper surface whereas the shorter petals have reddish striations on the underside only.


8th June 2005, River Chee, Chee Dale, Derbyshire. Photo: © RWD
The outer petals are heavily veined in red.


Sometimes the outer petals lack reddish streaks. Photo: © RWD


Photo: © RWD
Plan view of flower.


6th Sept 2005, Leeds &Liverpool Canal, Tarleton. Photo: © RWD
Large 3-sided green seed pods replace the flowers. They contain many brown seeds which float on water to germinate in the vicinity.


6th Sept 2005, Leeds &Liverpool Canal, Tarleton. Photo: © RWD


12th Nov 2013, Macclesfield Canal, Marple. Photo: © RWD
The seeds within the pods.


12th Nov 2013, Macclesfield Canal, Marple. Photo: © RWD
When fully ripe the three pod sides splay wide open like an out-stretched palm.


20th Oct 2016, Macclesfield Canal, Macclesfield. Photo: © RWD
Split open manually so that your Author could better photograph the seeds, which then mostly proceeded to fell out.


20th Oct 2016, Macclesfield Canal, Macclesfield. Photo: © RWD
Opening another pod. The seeds are milk chocolate-brown and vary in shape, but most have at least two flat sides in order to pack in side by side, in two rows.


20th Oct 2016, Macclesfield Canal, Macclesfield. Photo: © RWD
The seeds in close-up. They are quite unlike those of the otherwise similar (but with a pale mauve coloured flower) Stinking Iris which has bright-red roughly spherical seeds in the pod which look like berries.


Photo: © RWD
The long stiff, broad sword-shaped leaves have parallel veins and are finely ridged.


Some similarities to : Daffodils, but daffodils don't grow in water or have three large petals flopping down.

Uniquely identifiable characteristics: There is no other plant quite like this.

Distinguishing Feature : The large yellow petals in triplets at 120 degrees. Always grows in water.

Like many aquatic plants, this too has petals in three's.

The poisonous cardiac glycoside Iridin (aka Irisin) is found in the leaves and rhizomes of Yellow Iris. If ingested symptoms include nausea, elevated temperature, vomiting, abdominal pain, severe purgation can result. It is dangerous to animals. Most irises contain this substance. It is also found in the roots of the Violet Family.

Yellow Iris spreads underwater by thick rhizomes in anoxic conditions, and is able to withstand quite acidic conditions (low pH). It is selectively absorbs heavy metals and has been used to help clean up heavy metal pollution, provided that pollution occurs in water, for Yellow Iris needs wet conditions and will not grow on dry land.

The rhizomes were used to produce both a black dye and an ink.

Yellow Flag is a perennial with stout stems and an under-ground horizontal tuber. It is poisonous.

Irisquinone is an contact allergen found in Yellow Flag, which is very similar to one of the quinones (Primin) found in species of Primrose, some species of which are notoriously allergenic, causing contact dermatitis. Compare with GeranylGeranyl-Benzoquinone and other benzoquinones with long aliphatic side chains.


  Iris pseudacorus  ⇐ Global Aspect ⇒ Iridaceae  

Distribution
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 BSBI maps
genus8iris
Iris
(Irises)

YELLOW IRIS

YELLOW FLAG

Iris pseudacorus

Iris Family [Iridaceae]  

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