Jacobaea vulgaris, syn. Senecio jacobaea,[2] is a very common wild flower in the family Asteraceae that is native to northern Eurasia, usually in dry, open places, and has also been widely distributed as a weed elsewhere.
Common names include ragwort, common ragwort,[4]stinking willie,[5]tansy ragwort, benweed, St. James-wort, stinking nanny/ninny/willy, staggerwort, dog standard, cankerwort, stammerwort. In the western United States it is generally known as tansy ragwort, or tansy, though its resemblance to the true tansy is superficial.[citation needed]
In some countries it is an invasive species and regarded as a noxious weed. In the UK, where it is native, it is often unwanted because of its toxic effect for cattle and horses, but it is also valued for its nectar production which feeds insect pollinators and its ecological importance is thus considered significant.
Description
The plant is generally considered to be biennial but it has the tendency to exhibit perennial properties under certain cultural conditions (such as when subjected to repeated grazing or mowing).[6] The stems are erect, straight, have no or few hairs, and reach a height of 0.3–2.0 metres (1ft 0in– 6ft 7in). The leaves are pinnately lobed and the end lobe is blunt.[7] The many names that include the word "stinking" (and Mare's Fart) arise because of the unpleasant smell of the leaves. The hermaphrodite flower heads are 1.5–2.5 centimetres (0.59–0.98in) diameter, and are borne in dense, flat-topped clusters; the florets are bright yellow. It has a long flowering period lasting from June to November (in the Northern Hemisphere).
Pollination is by a wide range of bees, flies and moths and butterflies. Over a season, one plant may produce 2,000 to 2,500 yellow flowers in 20- to 60-headed, flat-topped corymbs. The achenes have dandelion-like groups of prickly hairs called pappuses, which help seed dispersal by the wind.[8][9] The number of seeds produced may be as large as 75,000 to 120,000, although in its native range in Eurasia very few of these would grow into new plants and research has shown that most seeds do not travel a great distance from the parent plant.[10][11]
Taxonomy
Two subspecies are accepted:
Jacobaea vulgaris ssp. vulgaris - the typical plant, with ray florets present.
Jacobaea vulgaris ssp. dunensis - the ray florets are missing.
Distribution
Ragwort is native to the Eurasian continent. In Europe it is widely spread, from Scandinavia to the Mediterranean.[citation needed] In Britain and Ireland, where it is native, it is listed as a noxious weed.[12]
Ragwort is abundant in waste land, waysides and grazing pastures.[13] It can be found along road sides, and grows in all cool and high rainfall areas.[citation needed]
It has been introduced in many other regions, and is listed as a weed in many. These include:[citation needed]
Australasia: a widespread weed in New Zealand and Australia.
Ecological importance
Although the plant is often unwanted by landowners because of its toxic effect for cattle and horses, and because it is considered a weed by many, it provides a great deal of nectar for pollinators. It was rated in the top 10 for most nectar production (nectar per unit cover per year) in a UK plants survey conducted by the AgriLand project which is supported by the UK Insect Pollinators Initiative.[14] It also was the top producer of nectar sugar in another study in Britain, with a production per floral unit of (2921 ± 448μg).[15]
In the United Kingdom, where the plant is native, ragwort provides a home and food source to at least 77 insect species. Thirty of these species of invertebrate use ragwort exclusively as their food source[16] and there are another 22 species where ragwort forms a significant part of their diet.
English Nature identifies a further 117 species that use ragwort as a nectar source whilst travelling between feeding and breeding sites, or between metapopulations.[16] These consist mainly of solitary bees, hoverflies, moths, and butterflies such as the small copper butterfly (Lycaena phlaeas). Pollen is collected by solitary bees.[17]
Besides the fact that ragwort is very attractive to such a vast array of insects, some of these are very rare indeed. Of the 30 species that specifically feed on ragwort alone, seven are officially deemed nationally scarce. A further three species are on the IUCN Red List. In short, ragwort is an exclusive food source for ten rare or threatened insect species, including the cinnabar moth (Tyria jacobaeae),[18] the picture winged fly (Campiglossa malaris), the scarce clouded knot horn moth (Homoeosoma nimbella), and the Sussex emerald moth (Thalera fimbrialis).[16] The Sussex Emerald has been labelled a Priority Species in the United Kingdom Biodiversity Action Plan. A priority species is one which is "scarce, threatened and declining".[19] The remainder of the ten threatened species include three species of leaf beetle, another picture-winged fly, and three micro moths. All of these species are Nationally Scarce B, with one leaf beetle categorised as Nationally Scarce A.[16]
The most common of those species that are totally reliant on ragwort for their survival is the cinnabar moth. The cinnabar is a United Kingdom Biodiversity Action Plan Species, its status described as "common and widespread, but rapidly declining".[19]
Poisonous effects
Structure of senecionine
Ragwort contains many different alkaloids, making it poisonous to certain animals. (EHC 80,section 9.1.4). Alkaloids which have been found in the plant confirmed by the WHO report EHC 80 are -- jacobine, jaconine, jacozine, otosenine, retrorsine, seneciphylline, senecionine, and senkirkine (p.322 Appendix II). There is a strong variation between plants from the same location in distribution between the possible alkaloids and even the absolute amount of alkaloids varies drastically.[20]
Ragwort is of concern to people who keep horses and cattle.[21][22] In areas of the world where ragwort is a native plant, such as Britain and continental Europe, documented cases of proven poisoning are rare.[23] Horses do not normally eat fresh ragwort due to its bitter taste.[citation needed] The result, if sufficient quantity is consumed, can be irreversible cirrhosis of the liver of a form identified as megalocytosis where cells are abnormally enlarged. Signs that a horse has been poisoned include yellow mucous membranes, depression, and lack of coordination.[24]
There is no definitive test for the poisoning however, since megalocytosis is not a change in the liver which is specific to ragwort poisoning. It is also seen in poisoning by other alkylating agents, such as nitrosamines and aflatoxins.[25] Aflatoxins are a common contaminant formed in feedstuffs by moulds. Research in the United Kingdom has produced results showing megalocytosis, which may be due to various causes, to be a relatively uncommon cause of liver disease in horses.[26]
The alkaloid does not actually accumulate in the liver but a breakdown product can damage DNA and progressively kills cells.[citation needed] About 3-7% of the body weight is sometimes claimed as deadly for horses,[citation needed] but an example in the scientific literature exists of a horse surviving being fed over 20% of its body weight.[citation needed] The effect of low doses is lessened by the destruction of the original alkaloids by the action of bacteria in the digestive tract before they reach the bloodstream. There is no known antidote or cure to poisoning, but examples are known from the scientific literature of horses making a full recovery once consumption has been stopped.[27][28]
The alkaloids can be absorbed in small quantities through the skin but studies have shown that the absorption is very much less than by ingestion. Also they are in the N-oxide form which only becomes toxic after conversion inside the digestive tract and they will be excreted harmlessly.[29]
Some sensitive individuals can suffer from an allergic reaction because ragwort, like many members of the family Compositae, contains sesquiterpene lactones which can cause compositae dermatitis. These are different from the pyrrolizidine alkaloids which are responsible for the toxic effects.
Honey collected from ragwort has been found to contain small quantities of jacoline, jacobine, jacozine, senecionine, and seneciphylline, but the quantities have been judged as too minute to be of concern.[30]
Control
As indicated above, common ragwort has become a problem in several areas in which it has been introduced, and various methods are employed to help prevent its spread.
In many Australian states ragwort has been declared a noxious weed, and landholders are required to remove it from their property by law.[citation needed] In the island state of Tasmania, ragwort is responsible for more than half of the total costs of that state's control of invasive species. The species has been calculated as the 8th most expensive invasive species in terms of cost to Australian farmers, at over A$500m over 60 years.[31]
It is also legislated as a noxious weed in New Zealand, where farmers sometimes bring in helicopters to spray their farms if the ragwort is too widespread.[citation needed]
In the United Kingdom, common ragwort (Senecio jacobaea) is one of the five plants named as an injurious weed under the provisions of the Weeds Act 1959. The word injurious in this context indicates that it could be harmful to agriculture, not that it is dangerous to animals, as all the other injurious weeds listed are non-toxic. Under the terms of this Act, a land occupier can be required by the Secretary of State for Environment, Food and Rural Affairs to prevent the spread of the plant. However, the growth of the plant is not made illegal by the Act and there is no statutory obligation for control placed upon landowners in general.[34]
The Ragwort Control Act 2003 provides for a code of practice, which the government states is guidance,[35] on ragwort and does not place any further legal responsibilities on landowners to control the plant.[36]
Biological control
Flowering plant with cinnabar moth caterpillars
Ragwort is a food plant for the larvae of Cochylis atricapitana, Phycitodes maritima, and Phycitodes saxicolais. Ragwort is best known as the food of caterpillars of the cinnabar mothTyria jacobaeae. They absorb alkaloids from the plant and become distasteful to predators, a fact advertised by the black and yellow warning colours. The red and black, day-flying adult moth is also distasteful to many potential predators. The moth is used as a control for ragwort in countries in which it has been introduced and become a problem, like New Zealand and the western United States.[37] As both larvae and adults are distinctly colored and marked, identification of cinnabars is easy outside of their natural range, and grounds and range keepers can quickly recognize them. In both countries, the tansy ragwort flea beetle (Longitarsus jacobaeae) has been introduced to combat the plant. Another beetle, Longitarsus ganglbaueri, also feeds on ragwort, but will feed on other plants as well, making it an unsuitable biological control.[38] Another biological control agent introduced in the western United States is the ragwort seed fly, although it is not considered very effective at controlling ragwort.[39] The biological control of ragwort was already used in the 1930s.[40]
The leaves can be used to obtain a good green dye, although it fades. The flowers can be used to produce a dye that is yellow when the fabric is mordanted with alum. Brown and orange dyes are also reported.[41]
Literature, poetry and mythology
Ragwort thou humble flower
The Greek physician Pedanius Dioscorides (c.40-90 CE) recommended the herb. The two "fathers" of herbalism, Gerard and Culpeper, also recommended the herb. Culpeper was an astrological botanist and thought the plant was "under the command of Dame Venus, and [it] cleanses, digests, and discusses."[42]
The poet John Clare had a more positive opinion of the plant, as revealed in this poem of 1831:
Ragwort thou humble flower with tattered leaves
I love to see thee come and litter gold...
Thy waste of shining blossoms richly shields
The sun tanned sward in splendid hues that burn
So bright and glaring that the very light
Of the rich sunshine doth to paleness turn
And seems but very shadows in thy sight.
The ragwort, under its Manx name Cushag, is the national flower of the Isle of Man[43] According to one story King Orry chose as his emblem the cushag flower, as its twelve petals represent one of the isles of the Kingdom of Mann and the Isles: the Isle of Man, Arran, Bute, Islay, Jura, Mull, Iona, Eigg, Rum, Skye, Raasay, and the Outer Hebrides.[citation needed] The ragwort, in fact, usually has thirteen petals. The Manx poet Josephine Kermode (1852–1937) wrote the following poem about the Cushag:
Donald Macalastair of Druim-a-ghinnir on the Isle of Arran told a story of the fairies journeying to Ireland. The ragwort was their transport and every one of them picked a plant, sat astride and arrived in Ireland in an instant.[44]
Senecio is a genus of flowering plants in the daisy family (Asteraceae) that includes ragworts and groundsels.
Senecio vulgaris, often known by the common names groundsel and old-man-in-the-spring, is a flowering plant in the family Asteraceae. It is an annual herb, native to the Palaearctic and widely naturalised as a ruderal species in suitable disturbed habitats worldwide.
Echium plantagineum, commonly known as purple viper's-bugloss or Patterson's curse, is a species of the genus Echium native to western and southern Europe, northern Africa, and southwestern Asia. It has also been introduced to Australia, South Africa, and United States, where it is an invasive weed. Due to a high concentration of pyrrolizidine alkaloids, it is poisonous to grazing livestock, especially those with simple digestive systems, such as horses.
Tansy is a perennial, herbaceous flowering plant in the genus Tanacetum in the aster family, native to temperate Europe and Asia. It has been introduced to other parts of the world, including North America, and in some areas has become invasive. It is also known as common tansy, bitter buttons, cow bitter, or golden buttons. The Latin word vulgare means "common".
The cinnabar moth is a brightly coloured arctiid moth found as a native species in Europe and western and central Asia then east across the Palearctic to Siberia to China. It has been introduced into New Zealand, Australia and North America to control ragwort, on which its larvae feed. The moth is named after the red mineral cinnabar because of the red patches on its predominantly black wings. The species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. Cinnabar moths are about 20 mm (0.79 in) long and have a wingspan of 32–42 mm (1.3–1.7 in).
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or livestock. Most noxious weeds have been introduced into an ecosystem by ignorance, mismanagement, or accident. Some noxious weeds are native. Typically they are plants that grow aggressively, multiply quickly without natural controls, and display adverse effects through contact or ingestion. Noxious weeds are a large problem in many parts of the world, greatly affecting areas of agriculture, forest management, nature reserves, parks and other open space.
Ageratum conyzoides is native to Tropical America, especially Brazil, and is an invasive weed in many other regions. It is an herb that is 0.5–1 m. high, with ovate leaves 2–6 cm long, and flowers are white to mauve.
Packera aurea, commonly known as golden ragwort or simply ragwort, is a perennial flower in the family Asteraceae.
Senecio squalidus, known as Oxford ragwort, is a flowering plant in the daisy family Asteraceae. It is a yellow-flowered herbaceous plant, native to mountainous, rocky or volcanic areas, that has managed to find other homes on man-made and natural piles of rocks, war-ruined neighborhoods and even on stone walls. These habitats resemble its well drained natural rocky homeland. The plants have spread via the wind, rail and the activities of botanists. The travels of this short-lived perennial, biennial, or winter annual make it a good subject for studies of the evolution and ecology of flowering plants.
Ragwort may refer to a number of plant species:
Longitarsus jacobaeae is a species of flea beetle known as the tansy ragwort flea beetle. It is used as an agent of biological pest control against the nectar-rich noxious weed known as ragwort.
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 known as common comfrey or true comfrey. Other English names include boneset, knitbone, consound, and slippery-root. It is native to Europe, growing in damp, grassy places. It is locally frequent throughout Ireland and Britain on river banks and ditches. It occurs elsewhere, including North America, as an introduced species and sometimes a weed. The flowers are mostly visited by bumblebees. Internal or long-term topical use of comfrey is discouraged due to its strong potential to cause liver toxicity.
Senecio madagascariensis, also known as Madagascar ragwort, is a species of the genus Senecio and family Asteraceae that is native to Southern Africa. Other common names include Madagascar groundsel and fireweed. It has been included on the noxious weeds list for Hawaii and the reject list for Australia. S.madagascariensis is the diploid cytotype of S.inaequidens.
Conium maculatum, colloquially known as hemlock, poison hemlock or wild hemlock, is a highly poisonous flowering plant in the carrot family Apiaceae, native to Europe and North Africa. It is herbaceous without woody parts and has a biennial lifecycle. A hardy plant capable of living in a variety of environments, hemlock is widely naturalised in locations outside its native range, such as parts of Australia, West Asia, and North and South America, to which it has been introduced. It is capable of spreading and thereby becoming an invasive weed.
Senecionine is a toxic pyrrolizidine alkaloid isolated from various botanical sources. It takes its name from the Senecio genus and is produced by many different plants in that genus, including Jacobaea vulgaris. It has also been isolated from several other plants, including Brachyglottis repanda, Emilia, Erechtites hieraciifolius, Petasites, Syneilesis, Crotalaria, Caltha leptosepala, and Castilleja.
Pyrrolizidine alkaloidosis is a disease caused by chronic poisoning found in humans and other animals caused by ingesting poisonous plants which contain the natural chemical compounds known as pyrrolizidine alkaloids. Pyrrolizidine alkaloidosis can result in damage to the liver, kidneys, heart, brain, smooth muscles, lungs, DNA, lesions all over the body, and could be a potential cause of cancer. Pyrrolizidine alkaloidosis is known by many other names such as "Pictou Disease" in Canada and "Winton Disease" in New Zealand. Cereal crops and forage crops can sometimes become polluted with pyrrolizidine-containing seeds, resulting in the alkaloids contaminating flour and other foods, including milk from cows feeding on these plants.
Nyctemera annulata, the magpie moth, is a moth of the family Erebidae. The species was first described by Jean Baptiste Boisduval in 1832. It is endemic to New Zealand and found in all parts of the country.
Riddelliine is a chemical compound classified as a pyrrolizidine alkaloid. It was first isolated from Senecio riddellii and is also found in a variety of plants including Jacobaea vulgaris, Senecio vulgaris, and others plants in the genus Senecio.
Botanophila seneciella, the ragwort seed fly or ragwort seed head fly, is a fly species in the family Anthomyiidae.
↑ USDA, NRCS (n.d.). "Senecio jacobaea". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 9 November 2015.
↑ Poole, A. L.; Cairns, D. (1940). "Botanical Aspects of Ragwort (Senecio jacobaea L.) Control". Bulletin of the New Zealand Department of Science and Industrial Research. 82: 1–66.
↑ McEvoy, Peter B.; Cox, Caroline S. (1987). "Wind Dispersal Distances in Dimorphic Achenes of Ragwort, Senecio Jacobaea". Ecology. 68 (6): 2006–2015. doi:10.2307/1939891. JSTOR1939891. PMID29357152.
↑ Lessard, P.; Wilson, W. D.; Olander, H. J.; Rogers, Q. R.; Mendel, V. E. (1986). "Clinicopathologic study of horses surviving pyrrolizidine alkaloid (Senecio vulgaris) toxicosis". American Journal of Veterinary Research. 47 (8): 1776–80. PMID2875683.
↑ McEvoy, Peter; Cox, Caroline; Coombs, Eric (1991). "Successful Biological Control of Ragwort, Senecio Jacobaea, by Introduced Insects in Oregon". Ecological Applications. 1 (4): 430–442. doi:10.2307/1941900. JSTOR1941900. PMID27755672. S2CID21701854.
↑ D. A. McLAREN, J. E. IRESON, and R. M. KWONG (2000). "Biological Control of Ragwort (Senecio jacobaea L.) in Australia". Proceedings of the X International Symposium on Biological Control of Weeds: 67–79.{{cite journal}}: CS1 maint: multiple names: authors list (link)
↑ Support, Extension Web (12 June 2018). "Tansy Ragwort". Ag - Weed Management.
↑ Cameron, Ewen (1935). "A Study of the Natural Control of Ragwort (Senecio Jacobaea L.)". The Journal of Ecology. 23 (2): 265–322. doi:10.2307/2256123. JSTOR2256123.
↑ Grieve, Maud (1971). A Modern Herbal: The Medicinal, Culinary, Cosmetic and Economic Properties, Cultivation and Folk-lore of Herbs, Grasses, Fungi, Shrubs, & Trees with All Their Modern Scientific Uses, Volume 2.
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