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

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Iridaceae. It is native to Europe, western Asia and northwest Africa. Its

specific epithet In Taxonomy (biology), taxonomy, binomial nomenclature ("two-term naming system"), also called binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin gramm ...

''pseudacorus'' means "false acorus", referring to the similarity of its leaves to those of '' Acorus calamus'' (sweet flag), as they have a prominently veined mid-rib and sword-like shape. However, the two plants are not closely related.

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 ...

flowering

perennial plant In horticulture, the term perennial (''wikt:per-#Prefix, per-'' + ''wikt:-ennial#Suffix, -ennial'', "through the year") is used to differentiate a plant from shorter-lived annual plant, annuals and biennial plant, biennials. It has thus been d ...

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 soils. The plant spreads quickly, by both

rhizome In botany and dendrology, a rhizome ( ) is a modified subterranean plant stem that sends out roots and Shoot (botany), shoots from its Node (botany), nodes. Rhizomes are also called creeping rootstalks or just rootstalks. Rhizomes develop from ...

and water-dispersed seed. It fills a similar niche to that of ''

Typha ''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrushStreeter D, Hart-Davies C, Hardcastle A, Cole F, Harper L. 2009. ' ...

'' 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 The corn crake, corncrake or landrail (''Crex crex'') is a bird in the Rallidae, rail family. It breeds in Europe and Asia as far east as western China, and bird migration, migrates to Africa for the Northern Hemisphere's winter. It is a medium ...

. ''I. pseudacorus'' is one of two iris species native to the United Kingdom, the other being '' Iris foetidissima'' (stinking iris).

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''.

Cultivation

It is widely planted in

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

regions as an ornamental plant, with several

cultivar A cultivar is a kind of Horticulture, cultivated plant that people have selected for desired phenotypic trait, traits and which retains those traits when Plant propagation, propagated. Methods used to propagate cultivars include division, root a ...

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 artificial ...

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 ...

Award of Garden Merit The Award of Garden Merit (AGM) is a long-established award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions. It includes the full range of cultivated p ...

: * '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).

Invasive species

In some regions (including the US and

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

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

aquatic plant Aquatic plants, also referred to as hydrophytes, are vascular plants and Non-vascular plant, non-vascular plants that have adapted to live in aquatic ecosystem, aquatic environments (marine ecosystem, saltwater or freshwater ecosystem, freshwater ...

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 Connecticut ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Rhode Island to the east, Massachusetts to the north, New York (state), New York to the west, and Long Island Sound to the south. ...

Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

New Hampshire New Hampshire ( ) is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec t ...

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

North Carolina North Carolina ( ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, South Carolina to the south, Georgia (U.S. stat ...

Oregon Oregon ( , ) is a U.S. state, state in the Pacific Northwest region of the United States. It is a part of the Western U.S., with the Columbia River delineating much of Oregon's northern boundary with Washington (state), Washington, while t ...

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

Vermont Vermont () is a U.S. state, state in the New England region of the Northeastern United States. It borders Massachusetts to the south, New Hampshire to the east, New York (state), New York to the west, and the Provinces and territories of Ca ...

, Washington,

Wisconsin Wisconsin ( ) is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest of the United States. It borders Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michig ...

, and

West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...

Relationship to ''fleur-de-lis''

According to Pierre Augustin Boissier de Sauvages, an 18th-century French

naturalist Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

and

lexicographer Lexicography is the study of lexicons and the art of compiling dictionaries. It is divided into two separate academic disciplines: * Practical lexicography is the art or craft of compiling, writing and editing dictionary, dictionaries. * The ...

, the name ''

fleur-de-lis The ''fleur-de-lis'', also spelled ''fleur-de-lys'' (plural ''fleurs-de-lis'' or ''fleurs-de-lys''), is a common heraldic charge in the (stylized) shape of a lily (in French, and mean and respectively). Most notably, the ''fleur-de-lis'' ...

'' applied to the heraldic symbol may be related to ''Iris pseudacorus'' rather than to a lily, based on the shape and yellow colour of the flower.

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 a chemical element; it has Symbol (chemistry), symbol N and atomic number 7. Nitrogen is a Nonmetal (chemistry), nonmetal and the lightest member of pnictogen, group 15 of the periodic table, often called the Pnictogen, pnictogens. ...

and

phosphorus Phosphorus is a chemical element; it has Chemical symbol, symbol P and atomic number 15. All elemental forms of phosphorus are highly Reactivity (chemistry), reactive and are therefore never found in nature. They can nevertheless be prepared ar ...

) 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''
* {{Authority control 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