''Lythrum salicaria'' or purple loosestrife
[Flora of NW Europe]
''Lythrum salicaria''
is a
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 ...
belonging to the family
Lythraceae. It should not be confused with other plants sharing the name loosestrife that are members of the family
Primulaceae
The Primulaceae , commonly known as the primrose family (but not related to the evening primrose family), are a family of herbaceous and woody flowering plants including some favourite garden plants and wildflowers. Most are perennial though som ...
. Other names include spiked loosestrife and purple Lythrum. 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 ...
perennial
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 ...
is native to Europe and Asia, and possibly Australia.
Etymology and other names
The generic name ''Lythrum'' is derived from the Greek ‘lythron’, meaning blood, in reference to the flower colour in some species.
[Gledhill D. 1985. ''The Names of Plants''. Cambridge University Press ] However,
Pliny (A.D. 23-79) stated that ''Lythrum'' is named for
Lysimachus
Lysimachus (; Greek: Λυσίμαχος, ''Lysimachos''; c. 360 BC – 281 BC) was a Thessalian officer and successor of Alexander the Great, who in 306 BC, became King of Thrace, Asia Minor and Macedon.
Early life and career
Lysimachus was b ...
, an army general and friend of
Alexander the Great
Alexander III of Macedon ( grc, wikt:Ἀλέξανδρος, Ἀλέξανδρος, Alexandros; 20/21 July 356 BC – 10/11 June 323 BC), commonly known as Alexander the Great, was a king of the Ancient Greece, ancient Greek kingdom of Maced ...
. ‘’Lysimachus’’ is derived from the Greek ‘’lysis’’, meaning ‘’loosing’’ and ‘’mache’’, meaning strife.
[ Mitich LW. 1999. ''Lythrum salicaria'' L. ''Weed Technology'' 13: 843 – 846.]
The
specific epithet ''salicaria'' derives from the similarity of the leaves to those of willows or ''
Salix
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
'' species.
The English word loosestrife first appeared in written form in the 16th century. It was coined by English naturalist
William Turner in his 1548 work ''A New Herball'', in which he states: "
he plantmay in englishe be called red loosestryfe or purple loosestryfe."
Purple loosestrife was referred to several times as ‘Long Purples’ by
John Clare
John Clare (13 July 1793 – 20 May 1864) was an English poet. The son of a farm labourer, he became known for his celebrations of the English countryside and sorrows at its disruption. His work underwent major re-evaluation in the late 20th ce ...
, such as in his 1821 poem ''The Wildflower Nosegay'':
"Where on the water op’d the lily buds
And fine long purples shadow’d in the lake..."
— Volume II of ''The Village Minstrel and Other Poems'', John Clare, pg. 133
Description
''Lythrum salicaria'' can grow tall, forming
clonal colonies
A clonal colony or genet is a group of genetically identical individuals, such as plants, fungi, or bacteria, that have grown in a given location, all originating vegetatively, not sexually, from a single ancestor. In plants, an individual in s ...
or more in width, with numerous erect stems growing from a single woody root mass. The stems are reddish-purple and square in cross-section. The leaves are
lanceolate
The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...
, long and broad, downy and
sessile
Sessility, or sessile, may refer to:
* Sessility (motility), organisms which are not able to move about
* Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant
* Sessility (medicine), tumors and polyps that ...
, and arranged opposite or in whorls of three.
The flowers are reddish purple, in diameter, with six petals (occasionally five) and 12 stamens, and are clustered tightly in the
axil
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...
s of
bract
In botany, a bract is a modified or specialized leaf, especially one associated with a reproductive structure such as a flower, inflorescence axis or cone scale. Bracts are usually different from foliage leaves. They may be smaller, larger, or of ...
s or leaves; there are
three different flower types, with the stamens and style of different lengths, short, medium or long; each flower type can only be pollinated by one of the other types, not the same type, thus ensuring cross-pollination between different plants.
[Blamey, M. & Grey-Wilson, C. (1989). ''The Illustrated Flora of Britain and Northern Europe''. Hodder & Stoughton. .] The flowers are visited by many types of insects, and can be characterized by a generalized pollination syndrome
Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic (wind and water) or biotic, such as birds, bees, flies, and so forth through a process c ...
.
The fruit is a small capsule containing numerous minute seed
A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...
s. Flowering lasts throughout the summer. When the seeds are mature, the leaves often turn bright red through dehydration in early autumn; the red colour may last for almost two weeks. The dead stalks from previous growing seasons are brown.[
''L. salicaria'' is very variable in leaf shape and degree of hairiness, and a number of subspecies and varieties have been described, but it is now generally regarded as monotypic with none of these variants being considered of botanical significance. The species ''Lythrum intermedium'' Ledeb. ex Colla is also now considered synonymous.]
Distribution
''Lythrum salicaria'' is native to Europe, temperate Asia and northwest Africa. It is also naturalised in many temperate parts of the world, including parts of southern Africa, North America, and South America.[Med-Checklist: ''Lythrum salicaria''/ref>][Australian Plant Names Index]
''Lythrum salicaria''
/ref> The species was thought to be a recent introduction to Australia, but pre-colonial pollen samples have been found in New South Wales, indicating another route of introduction; the question is considered unresolved by Australian authorities.
Ecology
Found in ditches, wet meadows and marshes and along sides of lakes. In North America, purple loosestrife can invade sedge meadows
A hydrosere is a plant succession which occurs in an area of fresh water such as in oxbow lakes and kettle lakes. In time, an area of open freshwater will naturally dry out, ultimately becoming woodland. During this change, a range of different la ...
.
Associated insects
The flowers are pollinated by long-tongued insects, including bees and butterflies
Butterflies are insects in the macrolepidopteran clade Rhopalocera from the Order (biology), order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The ...
.[
A number of ]insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s use ''Lythrum salicaria'' as a food resource.
The black-margined loosestrife beetle '' Galerucella calmariensis'' is a brown beetle with a black line on its thorax. The adult feeds on the leaves of the plant, producing characteristic round holes. Its larvae destroy tender leaf buds and strip the tissue from the leaves. The golden loosestrife beetle '' Galerucella pusilla'' is nearly identical to ''G. calmariensis'', but usually lacks the black thoracic line. Its feeding habits are also quite similar to the other leaf beetle.
The loosestrife root weevil '' Hylobius transversovittatus'' is a large red nocturnal weevil, which spends its nights feeding on leaves and leaf buds. The larvae emerge from their eggs and immediately burrow into the root of the plant, which they feed on continuously for over a year. This root damage stunts the plant's growth and ability to create seeds. If several larvae inhabit the same root, the plant can be killed.
The loosestrife flower weevil '' Nanophyes marmoratus'' is a tiny weevil which lays a single egg in each flower. When the larvae emerge they eat the flowers' ovaries, and the plant is unable to create seeds. The larvae usually proceed to hollow out the flower buds and use them as safe places to pupate.
Caterpillar
Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths).
As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...
s of the engrailed moth (''Ectropis crepuscularia
The engrailed and small engrailed (''Ectropis crepuscularia'') are moths of the family Geometridae found from the British Isles through central and eastern Europe to the Russian Far East and Kazakhstan. The western Mediterranean and Asia Minor ...
''), a polyphagous geometer moth
The geometer moths are moths belonging to the family Geometridae of the insect order Lepidoptera, the moths and butterflies. Their scientific name derives from the Ancient Greek ''geo'' γεω (derivative form of or "the earth"), and ''metro ...
, also feed on purple loosestrife.
Cultivation, uses and impact
It has been used as an astringent
An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin ''adstringere'', which means "to bind fast". Calamine lotion, witch hazel, and yerba mansa, a Californian plant ...
medicinal herb
Medicinal plants, also called medicinal herbs, have been discovered and used in traditional medicine practices since prehistoric times. Plants synthesize hundreds of chemical compounds for various functions, including defense and protection ag ...
to treat diarrhea
Diarrhea, also spelled diarrhoea, is the condition of having at least three loose, liquid, or watery bowel movements each day. It often lasts for a few days and can result in dehydration due to fluid loss. Signs of dehydration often begin wi ...
and dysentery
Dysentery (UK pronunciation: , US: ), historically known as the bloody flux, is a type of gastroenteritis that results in bloody diarrhea. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation. Complications ...
; it is considered safe to use for all ages, including babies.[Plants for a Future]
''Lythrum salicaria''
/ref> It is also cultivated as an ornamental plant
Ornamental plants or garden plants are plants that are primarily grown for their beauty but also for qualities such as scent or how they shape physical space. Many flowering plants and garden varieties tend to be specially bred cultivars that i ...
in gardens, and is particularly associated with damp, poorly drained locations such as marshes, bogs and watersides. However, it will tolerate drier conditions. The flowers are showy and bright, and a number of 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 have been selected for variation in flower colour, including:
* 'Atropurpureum' with dark purple flowers
* 'Brightness' with deep pink flowers
* 'Happy' with red flowers on a short () stem
* 'Purple Spires' with purple flowers on a tall stem
* 'Roseum Superbum' with large pink flowers.[Huxley, A., ed. (1992). ''New RHS Dictionary of Gardening''. Macmillan .]
The cultivars ‘Blush’ with blush-pink flowers, and 'Feuerkerze' with rose-red flowers 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
The Award of Garden Merit (AGM) is a long-established annual award for plants by the British Royal Horticultural Society (RHS). It is based on assessment of the plants' performance under UK growing conditions.
History
The Award of Garden Merit ...
.
It has also been introduced in many areas of North America by bee keepers, due to its abundance of flowers which provide an important source of nectar
Nectar is a sugar-rich liquid produced by plants in glands called nectaries or nectarines, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists ...
.
As an invasive species
The purple loosestrife has been introduced into temperate New Zealand
New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...
and North America
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
where it is now widely naturalised
Naturalization (or naturalisation) is the legal act or process by which a non-citizen of a country may acquire citizenship or nationality of that country. It may be done automatically by a statute, i.e., without any effort on the part of the i ...
(spreading on its own) and officially listed in some controlling agents. Infestations result in dramatic disruption in water flow in rivers and canals, and a sharp decline in biological diversity
Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') lev ...
as native food and cover plant species, notably cattail
''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 bulrush or reedmace, in American English as reed, cattail, or punks, in A ...
s, are completely crowded out, and the life cycles of organisms from waterfowl to amphibians to algae are affected.
A single plant may produce up to 2.7 million tiny seeds annually. Easily carried by wind and water, the seeds germinate in moist soils after overwintering. The plant can also sprout anew from pieces of root left in the soil or water. Once established, loosestrife stands are difficult and costly to remove by mechanical and chemical means.
Plants marketed under the name "European wand loosestrife" (''L. virgatum'') are the same species despite the different name. In some cases the plants sold are sterile, which is preferable.
In North America, purple loosestrife may be distinguished from similar native plants (e.g., fireweed
''Chamaenerion angustifolium'' is a perennial herbaceous flowering plant in the willowherb family Onagraceae. It is known in North America as fireweed, in some parts of Canada as great willowherb, in Britain and Ireland as rosebay willowherb. ...
''Chamerion angustifolium'', blue vervain ''Verbena hastata'', Liatris
''Liatris'' (), commonly known as gayfeather and blazing star. is a genus of flowering plants in the tribe Eupatorieae within the family Asteraceae native to North America (Canada, United States, Mexico and the Bahamas). Some species are used ...
''Liatris'' spp., and spiraea
''Spiraea'' , sometimes spelled spirea in common names, and commonly known as meadowsweets or steeplebushes, is a genus of about 80 to 100 species (''Spiraea douglasii
''Spiraea douglasii'' is a species of flowering plant in the rose family native to western North America. Common names include hardhack, hardhack steeplebush, Douglas' spirea, douglasspirea, steeplebush, and rose spirea.
Description
''Spiraea do ...
'') by its angular stalks which are square in outline, as well as by its leaves, which are in pairs that alternate at right angle and are not serrated.
Biological control
Purple loosestrife provides a model of successful biological pest control. Research began in 1985 and today the plant is managed well with a number of insects that feed on it. Five species of beetle
Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...
use purple loosestrife as their natural food source, and they can do significant damage to the plant. The beetles used as biological control agents include two species of leaf beetle
The insects of the beetle family Chrysomelidae are commonly known as leaf beetles, and include over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making up one of the largest and most commonly encountered of all beetle ...
: '' Galerucella calmariensis'' and '' Galerucella pusilla''; and three species of weevil
Weevils are beetles belonging to the Taxonomic rank, superfamily Curculionoidea, known for their elongated snouts. They are usually small, less than in length, and Herbivore, herbivorous. Approximately 97,000 species of weevils are known. They b ...
: '' Hylobius transversovittatus'', '' Nanophyes breves'', and '' Nanophyes marmoratus''. Infestations of either of the '' Galerucella'' species is extremely effective in wiping out a stand of purple loosestrife, defoliating up to 100% of the plants in an area. The moth ''Ectropis crepuscularia
The engrailed and small engrailed (''Ectropis crepuscularia'') are moths of the family Geometridae found from the British Isles through central and eastern Europe to the Russian Far East and Kazakhstan. The western Mediterranean and Asia Minor ...
'' is polyphagous and a pest species itself, and unsuitable for biological control.
References
External links
Invading Species.com
Ontario Ministry of Natural Resources and Ontario Federation of Anglers and Hunters
Species Profile - Purple Loosestrife (''Lythrum salicaria'')
National Invasive Species Information Center, United States National Agricultural Library
The United States National Agricultural Library (NAL) is one of the world's largest agricultural research libraries, and serves as a national library of the United States and as the library of the United States Department of Agriculture. Located ...
. Lists general information and resources for Purple Loosestrife.
{{Taxonbar, from=Q157513
salicaria
Flora of Europe
Flora of temperate Asia
Flora of tropical Asia
Flora of North Africa
Flora of Queensland
Flora of South Australia
Flora of Tasmania
Flora of Victoria (Australia)
Myrtales of Australia
Plants described in 1753
Taxa named by Carl Linnaeus