Terry Whittaker / Water vole (Arvicola amphibius) feeding on Yellow flag iris (Iris pseudacorus) seed pods, Kent, England, UK. October.

Sven Zacek / Yellow Flag Iris (Iris pseudacorus) flowering in birch forest. Estonia, Europe, June.

Russell Cooper / Banded Demoiselle (Calopteryx splendens) male at rest on Yellow Flag Iris flower bud (Iris pseudacorus) Morden, South London. England, UK.

Wild Wonders of Europe / Allofs / Flowering Yellow iris (Iris pseudacorus) Camargue, France, May 2009

Dave Bevan / Female Four-spotted chaser (Libellula quadrimaculata) landing and taking off from a Yellow iris (Iris pseudacorus) flower, Norfolk, England, UK, June.

Juan Carlos Munoz / Yellow flag iris (Iris pseudacorus), Liendo, Cantabria, Spain. May.

Chris Mattison / Yellow Iris (Iris pseudacorus) open seedpod with seeds. Whitelye Common, Monmouthshire, Wales, UK, October

Terry Whittaker / Water vole (Arvicola amphibius) feeding on Yellow flag iris (Iris pseudacorus) seed pods, Kent, England, UK. October.

Terry Whittaker / Water vole (Arvicola amphibius) feeding on seed pods of Flag iris (Iris pseudacorus ), Kent, England, UK. October.

Ingo Arndt / Yellow iris {Iris pseudacorus} flower, Germany

MYN / Dirk Funhoff / Yellow flag iris (Iris pseudacorus) showing reproductive parts, Büchelberg, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Yellow flag iris (Iris pseudacorus), Büchelberg, Germany. Meetyourneighbours.net project.

MYN / Dirk Funhoff / Yellow flag iris (Iris pseudacorus), Büchelberg, Pfalz, Germany. May. Meetyourneighbours.net project

MYN / Dirk Funhoff / Yellow flag iris (Iris pseudacorus), Büchelberg, Pfalz, Germany. May. Meetyourneighbours.net project

Nick Upton / Teresa Sinclair watching a Short-haired bumblebee queen (Bombus subterraneus) nectaring on Yellow flag iris flowers (Iris pseudacorus) after releasing it during a UK reintroduction project run by the...

Nick Upton / Short-haired bumblebee queen (Bombus subterraneus) collected in Sweden nectaring on a Yellow flag iris flower (Iris pseudacorus) with its long tongue after release during a UK reintroduction project r...

Ross Hoddinott / Newly emerged Emperor dragonfly (Anax imperator) resting on Yellow iris (Iris pseudacorus) Broxwater, Cornwall, UK. June 2015.

Pascal Tordeux / Yellow flag iris (Iris pseudacorus) in pond with reflections of clouds, medicinal plant. France, May.

Pascal Tordeux / Yellow flag iris (Iris pseudacorus) not yet in flower, at pond edge, medicinal plant. France, April.

Chris Mattison / Flag iris (Iris pseudacorus) on black background. Focus stacked image.

Heike Odermatt / Bogbean (Menyanthes trifoliata) and Yellow Iris (Iris pseudacorus) flowering at edge of coastal lagoon, De Bollekammer Nature Reserve, Texel, Netherlands

Terry Whittaker / Water vole (Arvicola amphibius) feeding on Yellow flag (Iris pseudacorus) seed pod, Kent, England, UK, September.

Terry Whittaker / Water vole (Arvicola amphibius) feeding on Yellow flag (Iris pseudacorus) seed pods, Kent, England, UK, September. Contrived situation.

Terry Whittaker / Water vole (Arvicola amphibius) biting off Yellow flag (Iris pseudacorus) seed pod, Kent, England, UK, October. Contrived situation. Highly commended in the Animal Behaviour category of BWPA Competiti...

Terry Whittaker / Water vole (Arvicola amphibius) standing on hind legs feeding on Yellow flag (Iris pseudacorus) seed pod, Kent, England, UK, October. Contrived situation.

Nick Upton / Yellow flag irises (Iris pseudacorus) flowering in a ditch in a damp lowland meadow with a Snout / Duck-billed Hoverfly (Rhingia campestris) resting on a petal, Wiltshire, UK, June.

Nick Upton / Yellow flag irises (Iris pseudacorus) flowering in a ditch in a damp lowland meadow, Wiltshire, UK, June.

Fabrice Cahez / Yellow flag iris (Iris pseudacorus) flower, Vosges, France, June.

Colin Varndell / Female Common yellow dung fly (Scathophaga stercoraria) resting on a Yellow flag iris (Iris pseudacorus) flower, Dorset, England, UK, June

David Pattyn / Yellow flag iris (Iris pseudacorus) in a lake, Texel Island, Wadden Sea, The Netherlands June

Will Watson / Watercress (Rorippa nasturtium-aquaticum) and Yellow flag iris (Iris pseudacorus) growing in spring-fed pond, with backdrop of ancient woodland, Herefordshire, England, June 2008.

David Woodfall / Yellow flag iris (Iris peudacorus ) and Greater water dock ( Rumex hydropathum ) in overgrown Alder wetland, Oxwich National Nature reserve, Gower, Wales, UK, June

MYN / Denis Palanque / Orb web spider (Meta segmentata) on Yellow flag iris (Iris pseudacorus) wetlands, Optevoz, Isere, Rhones-Alpes, France, April. meetyourneighbours.net project

MYN / Denis Palanque / Yellow flag iris (Iris pseudacorus) wetlands, Optevoz, Isere, Rhones-Alpes, France, April. meetyourneighbours.net project

Adrian Davies / Yellow Iris (Iris pseudacorus) UK

Alan Williams / Yellow flag iris (Iris pseudacorus) bed growing on ruined croft, South Uist, Outer Hebrides, Scotland, UK, May 2011

Ernie Janes / Yellow Flag Iris (Iris psueudacorus) and Banded Snail (Cepaea nemoralis) North Norfolk, UK, June

Philippe Clement / Yellow Iris / Yellow Flag (Iris pseudacorus) in flower. Belgium, May.

Philippe Clement / Yellow Iris / Yellow Flag (Iris pseudacorus) in flower. Belgium, May.

Adrian Davies / Yellow Iris (Iris pseudacorus), unopened buds. UK, May.

MYN / Niall Benvie / Yellow iris (Iris pseudacorus) flower on white background, Scotland, UK, June meetyourneighbours.net project

MYN / Niall Benvie / Yellow iris (Iris pseudacorus) flower on white background, Scotland, UK, June meetyourneighbours.net project

Nick Upton / Yellow flag irises (Iris pseudacorus) growing alongside a drainage channel. The Camargue, France, May.

Donald M. Jones / Yellow-headed Blackbird (Xanthocephalus xanthocephalus) male calling from blooming Yellow Iris (Iris pseudacorus), western Montana

Wild Wonders of Europe / della Ferrera / Yellow flag iris (Iris pseudacorus) in flower and Yellow water lily (Nuphar lutea) leaves on water, Hutovo Blato Nature Park, Bosnia and Herzegovina, May 2009

Michel Poinsignon / Yellow iris {Iris pseudacorus} and Cotton grass {Eriophorum sp} Lorraine, France

Wild Wonders of Europe / della Ferrera / Yellow flag iris (Iris pseudacorus) flowers and Yellow water lily (Nuphar lutea) leaves on water, with White willow (Salix alba) trees along a channel in the Hutovo Blato Nature Park, Bosnia and Herze...

Bernard Castelein / Cow wading in the water and Yellow Flag irises (Iris pseudacorus) flowering around dune lake in the Grote Vlake, Texel, The Netherlands

Bernard Castelein / Yellow Flag irises (Iris pseudacorus) flowering around dune lake in the Grote Vlake, Texel, The Netherlands

Bernard Castelein / Eurasian / White Spoonbill (Platalea leucorodia) in wetlands with Yellow Flag iris (Iris pseudacorus), Texel, the Netherlands

Juan Carlos Munoz / Yellow iris (Iris pseudacorus) flowering in wetlands, Andalucia, Spain, March

Juan Carlos Munoz / Yellow iris (Iris pseudacorus) flowering in wetlands, Andalucia, Spain, March

Juan Carlos Munoz / Yellow iris (Iris pseudacorus) flowering in wetlands, Andalucia, Spain, March

Martin Gabriel / Stands of Yellow iris (Iris pseudacorus) along the White Laber river, near Dietfurt, Bavaria, Germany, May 2007.

Mark Yates / Southern hawker dragonfly (Aeshna cyanea) resting on yellow iris (Iris pseudacorus) UK

Bernard Castelein / Dew-covered Yellow iris {Iris pseudacorus} buds, Belgium

David Pike / Yellow Flag {Iris pseudacorus} River Nene, Water Newton, Cambridgeshire, UK

MYN / Niall Benvie / Yellow iris {Iris pseudacorus} UK, June meetyourneighbours.net project

Willem Kolvoort / Underwater view of Yellow iris plant (Iris pseudacorus) showing tuber, Lake Naarden, Holland

Willem Kolvoort / Split level view of Yellow iris (Iris pseudacorus) growing by side of sand winning pit, Holland

GEORGETTE DOUWMA / Yellow iris {Iris pseudacorus} UK.

Niall Benvie / Yellow iris {Iris pseudacorus} flower, Estonia.

Philippe Clement / Yellow / Flag iris {Iris pseudacorus} Belgium

Bernard Castelein / Yellow iris {Iris pseudacorus} Belgium

Adrian Davies / Yellow iris, Iris pseudacorus, South England, UK, Europe.

Adrian Davies / Yellow iris seed heads (Iris pseudacorus) South England, UK, Europe

Bernard Castelein / Yellow iris flower and morning dew {Iris pseudacorus} Belgium, Europe

Bernard Castelein / Yellow iris flower about to unfurl {Iris pseudacorus} Belgium, Europe

Artur Tabor / Yellow / Flag iris {Iris pseudocorus} flowering in woodland. Poleski NP, Poland

Robert Thompson / Yellow iris (Iris pseudacorus) flowering beside lake, Hillsborough Park, County Down, Northern Ireland, UK

Robin Chittenden / Iris sawfly (Rhadinoceraea micans) caterpillar on Flag Iris (Iris pseudacorus) leaf, Norfolk, England, UK. June.

Nigel Cattlin / Two Iris sawfly (Rhadinoceraea micans) larvae feeding on the leaves of a Yellow flag iris (Iris pseudacorus), Berkshire, UK. June.

Ross Hoddinott / Broad-bodied chaser dragonfly (Libellula depressa) resting on Yellow iris (Iris pseudacorus) leaves, Broxwater, Cornwall, UK, April.

Ashley Cooper / Ragged robin (Silene flos-cuculi), Orchids (Orchidaceae) and Yellow flag iris (Iris pseudacorus) flowering in a damp, marshy meadow, Ling Ness, South Nesting, Shetland, Scotland, UK. June.

Ashley Cooper / Yellow flag iris (Iris pseudacorus) beds at Upper Urafirth, Shetland, Scotland, UK. July.

Terry Whittaker / Common carder bee (Bombus pascuorum) enters frame and feeds on nectar from flag iris (Iris Pseudocorus) before leaving frame, Greater Manchester, June.

Terry Whittaker / Garden bumblebee (Bombus hortorum) feeding on nectar from flag iris (Iris Pseudocorus) before leaving frame, Greater Manchester, June.

Nick Upton / Yellow flag iris (Iris pseudacorus) and Common cottongrass (Eriophorum angustifolium) flowering in a damp meadow bordering Kenfig Pool, Kenfig National Nature Reserve, Glamorgan, Wales, UK, June.

Nick Upton / Yellow flag iris (Iris pseudacorus) clump flowering in a damp sand dune slack, Kenfig National Nature Reserve, Glamorgan, Wales, UK, June.

Benjamin Olson / Common Loon (Gavia immer) on nest next to invasive Yellow Iris (Iris pseudacorus) flowers, northern Minnesota

Nick Upton / Female Goldenrod crab spider (Misumena vatia) camouflaged on Yellow flag iris (Iris pseudacorus) flower waiting for prey to land, Kenfig National Nature Reserve, Glamorgan, Wales, UK, June.

Nick Upton / Goldenrod crab spider (Misumena vatia) female well camouflaged on a Yellow flag iris (Iris pseudacorus) flower as it waits for prey to land. Kenfig NNR, Glamorgan, Wales, UK, June.

Paul Harcourt Davies / Yellow flag iris (Iris pseudacorus) in flower near wetland, Umbria, Italy. May.

Ross Hoddinott / Scarce Chaser dragonfly (Libellula fulva) resting on Yellow Flag Iris flower bud (Iris pseudacorus), Lower Tamar Lakes, Cornwall, UK. May .

Ross Hoddinott / Scarce Chaser dragonfly (Libellula fulva) resting on Yellow Flag Iris flower bud (Iris pseudacorus), Lower Tamar Lakes, Cornwall, UK. May .

Ann & Steve Toon / Yellow flag iris (Iris pseudacorus), Northumberland National Park, UK, May

Ross Hoddinott / Beautiful demoiselle damselfly (Calopteryx virgo) female resting on Yellow iris (Iris pseudacorus) bud. Cornwall, England, UK. May.

Ross Hoddinott / Beautiful demoiselle damselfly (Calopteryx virgo) female resting on Yellow iris (Iris pseudacorus) bud. Cornwall, England, UK. May.

Ross Hoddinott / Yellow iris (Iris pseudacorus). Cornwall, England, UK. May.

Linda Pitkin / Iris (Iris pseudacorus) flower and seed pod illustration.

Linda Pitkin / Yellow iris (Iris pseudacorus). River Thames Path, Hampton Court, Richmond Upon Thames, England, UK. May.

Ross Hoddinott / Male broad-bodied chaser (Libellula depressa) dragonfly resting on yellow flag iris flower bud (Iris pseudacorus), Broxwater, Cornwall, UK. May.