''Iris pseudacorus'', the yellow flag, yellow iris, or water flag, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Iridaceae Iridaceae is a family of plants in order Asparagales, taking its name from the irises, meaning rainbow, referring to its many colours. There are 66 accepted genera with a total of c. 2244 species worldwide (Christenhusz & Byng 2016). It include ...

. It is

native Native may refer to: People * Jus soli, citizenship by right of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Native Americans (disambiguation) In arts and entert ...

to Europe, western Asia and northwest Africa. Its specific epithet ''pseudacorus'' means "false acorus", referring to the similarity of its leaves to those of ''

Acorus calamus ''Acorus calamus'' (also called sweet flag, sway or muskrat root, among many common names) is a species of flowering plant with psychoactive chemicals. It is a tall wetland monocot of the family Acoraceae, in the genus '' Acorus.'' Although ...

'' (sweet flag), as they have a prominently veined mid-rib and sword-like shape. However, the two plants are not closely related. The flower is commonly attributed with the

fleur-de-lis The fleur-de-lis, also spelled fleur-de-lys (plural ''fleurs-de-lis'' or ''fleurs-de-lys''), is a lily (in French, and mean 'flower' and 'lily' respectively) that is used as a decorative design or symbol. The fleur-de-lis has been used in the ...

Description

This

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

flowering

perennial plant A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wide ...

grows to , or a rare tall, with erect leaves up to long and broad. The flowers are bright yellow, across, with the typical iris form. The fruit is a dry capsule long, containing numerous pale brown seeds. ''I. pseudacorus'' grows best in very wet conditions, and is common in wetlands, where it tolerates submersion, low pH, and

anoxic The term anoxia means a total depletion in the level of oxygen, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts: * Anoxic waters, sea water, fresh water or groundwater that are depleted of diss ...

soils. The plant spreads quickly, by both rhizome and water-dispersed seed. It fills a similar

niche Niche may refer to: Science *Developmental niche, a concept for understanding the cultural context of child development *Ecological niche, a term describing the relational position of an organism's species *Niche differentiation, in ecology, the ...

to that of '' Typha'' and often grows with it, though usually in shallower water. While it is primarily an aquatic or marginal plant, the rhizomes can survive prolonged dry conditions. Large ''I. pseudacorus'' stands in western Scotland form a very important feeding and breeding habitat for the endangered corncrake. ''I. pseudacorus'' is one of two iris species native to the United Kingdom, the other being ''

Iris foetidissima ''Iris foetidissima'', the stinking iris,Richard Fitter, Alastair Fitter and Marjorie Blamey gladdon, Gladwin iris, roast-beef plant, or stinking gladwin, is a species of flowering plant in the family Iridaceae, found in open woodland, hedgebank ...

'' (stinking iris). Both the petals and stem are toxic to animals and plants.

Nectar production

The plant was rated in second place for per day nectar production per flower in a UK plants survey conducted by the AgriLand project, which is supported by the UK Insect Pollinators Initiative. However, when number of flowers per floral unit, flower abundance, and phenology were taken into account, it dropped out of the top 10 for most nectar per unit cover per year, as did all plants that placed in the top ten, with the exception of common comfrey, ''

Symphytum officinale ''Symphytum officinale'' is a perennial flowering plant in the family Boraginaceae. Along with thirty four other species of ''Symphytum'', it is known as comfrey. To differentiate it from other members of the genus ''Symphytum'', this species is ...

''.

Cultivation

It is widely planted in

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout ...

regions as an ornamental plant, with several

cultivar A cultivar is a type of cultivated plant that people have selected for desired traits and when propagated retain those traits. Methods used to propagate cultivars include: division, root and stem cuttings, offsets, grafting, tissue culture ...

s selected for

bog garden A bog garden is a type of garden that employs permanently moist (but not waterlogged) soil to create a habitat for plants and creatures which thrive in such conditions. It may exploit existing poor drainage in the garden, or it may be artificiall ...

planting. The following cultivars have gained the

Royal Horticultural Society The Royal Horticultural Society (RHS), founded in 1804 as the Horticultural Society of London, is the UK's leading gardening charity. The RHS promotes horticulture through its five gardens at Wisley (Surrey), Hyde Hall (Essex), Harlow Carr (Nort ...

's Award of Garden Merit: * 'Roy Davidson' *'Variegata' (it has leaves that are edged with deep white stripes ) Other cultivars known include; ''Alba'' (with pale cream flowers) and ''Golden Fleece'' (with dark yellow flowers). It used to grow in the ditch of the fortified city of Mdina, on the island of Malta, where water was readily available, but since the renovation of the ditch it has since vanished from the area.

Invasive species

In some regions (including the USA and

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

) where it is not native, it has escaped from cultivation to establish itself as an invasive

aquatic plant Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...

which can create dense, monotypic stands, outcompeting other plants in the ecosystem. Where it is invasive, it is tough to remove on a large scale. Even ploughing the rhizomes is often ineffective. It has been banned in some areas but is still widely sold in others for use in gardens. ''Iris pseudacorus'' is reported as invasive in Connecticut, Delaware, Maryland, New Hampshire, North Carolina, Oregon, Tennessee, Virginia, Vermont, Washington, Wisconsin, and West Virginia.

Toxicity and uses

The plant's roots and leaves are poisonous. This plant has been used as a form of water treatment since it can take up macronutrients (such as

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

and

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

) through its roots, and is featured in many AS Level Biology practicals as its ability to grow in low pH levels makes it a useful indicator. It can also withstand high salinity levels in the water.

Gallery

Image:Iris pseudacorus from sweden.jpg File:Iris pseudacorus flower.jpg Image:Yellow Iris Iris pseudacorus Flower 1469px.jpg, Closeup Image:Iris_pseudacorus_01.jpg, ''Iris pseudacorus'' File:20140504Iris pseudacorus2.jpg, Flower Image:Illustration_Iris_pseudacorus0.jpg, ''Iris pseudacorus'' Image:Iris pseudacorus fruit.JPG, Fruit File:Iris pseudacorus LC0339.jpg, Whole plants

References

Flora Europaea: ''Iris pseudacorus''

External links

Plants for a Future: ''Iris pseudacorus''
* {{Taxonbar, from=Q21173 pseudacorus Flora of Europe Flora of North Africa Flora of Western Asia Garden plants of Africa Garden plants of Asia Garden plants of Europe Medicinal plants of Africa Medicinal plants of Asia Medicinal plants of Europe Plants described in 1753 Taxa named by Carl Linnaeus