Ragwort
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| Ragwort | ||||||||||||||
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| Senecio jacobaea |
Ragwort (Senecio jacobaea) is a common wild flower in the family Asteraceae that is found throughout Europe, usually in dry, open places, and has also been widely distributed as a weed elsewhere.
Alternative names include Tansy Ragwort, St. James-wort, Ragweed, Stinking Nanny/Ninny/Willy, Staggerwort, Dog Standard, Cankerwort, Stammerwort and Mare's Fart. In the western US it is generally known as "Tansy Ragwort", or even more confusingly "Tansy", though its resemblance to the true tansy is superficial at best. This is a potentially dangerous misuse of names, since the true tansy has been used for culinary purposes.
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Botanical description
The plant is biennual or perennial. The stems are erect, straight, have no or few hairs, and reach a height of 0.3-1.5 metres. The leaves are pinnately lobed and the end lobe is blunt. 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 cm 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.
Pollination is by a wide range of bees, flies and moths and butterflies. Over a season, one plant may produce 2000-2500 yellow flowers in 20- to 60-headed, flat-topped corymbs. This number of seeds produced may be as large as 75.000 - 200.000.
Taxonomy
Two subspecies are accepted:
- Senecio jacobaea ssp. jacobaea - the typical plant, with ray florets present.
- Senecio jacobaea ssp. dunensis - the ray florets are missing.
Distribution
Ragwort can be found along road sides and waste grounds, and grows in all cool and high rainfall areas.
The Ragwort is native to the Eurasian continent. In Europe it is widely spread, from Scandinavia to the Mediteranean. In Britain it is listed as a weed. In the USA it has been introduced, and is present mainly in the North West and North East: California, Idaho, Illinois, Maine, Massachusetts, Michigan, Montana, New Jersey, New York, Oregon, Pennsylvania, and Washington.
In South America it grows in Argentina, in Africa in the north, and on the Asian continent in India and Siberia. It is widespread weed in New Zealand.
Ecological aspects
Ragwort is foodplant for larvae Cochylis atricapitana, Phycitodes maritima, and Phycitodes saxicolais. Ragwort is best known as the food of caterpillars of the Cinnabar moth Tyria jacobaeae. The larvae absorb toxins from the plant and become poisonous themselves, a fact advertised by the black and yellow warning colours. The red, day-flying adult moth is also toxic or distasteful to many potential predators. The caterpillar stores the poison it eats in its skin. This way, when it casts its skin, it also gets rid of much of the poison it has accumulated.
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. In New Zealand, the ragwort flea beetle (Longitarsus jacobaea) has been introduced to combat the plant.
The flowers of Ragwort are eaten by the larvae of the Lime-speck Pug, Wormwood Pug, Golden-rod Pug, Double-striped Pug and Common Pug moths. The latter will also eat the leaves.
Ragwort is hostplant for Longitarsus ganglbaueri.
Poisonous effects
Ragwort contains many different alkaloids, making it poisonous to men and animals. Alkaloids which have been found in the plant are acetylerucifoline, (Z)-erucifoline, (E)-erucifoline, 21-hydroxyintegerrimine, integerrimine, jacoline, jaconine, jacobine, jacozine, riddelline, retrorsine, senecivernine, senecionine, seneciphylline, spartioidine, and usaramine.
Ragwort is the bane of people who keep horses, as well as cattle. Although horses do not normally eat Ragwort due to its bitter taste, if the growth is particularly dense or if it has been picked and dried out, and some is taken while grazing, the result can be irreversible cirrhosis of the liver. Signs that a horse has been poisoned include yellow mucus membranes, depression, and lack of coordination. Animals may also resort to the consumption of Ragwort when there is shortage of food. They even become addicted to it. Sheep, in marked contrast, eat small quantities of the plant with relish and without apparent harm. They seem to profit slightly from eating it, according to some reports the alkaloids kill worms in the sheeps stomach.
The great danger of Ragwort is that the toxin does not have an incidental but a cumulative effect. The toxin does not actually accumulate in the liver but a break down product can damage DNA and gradually kill cells. About 3-7% of the body weight is deadly for horses. It makes no difference whether this amount is consumed in a few months or over 10 years. However because of the mode of poisoning is through affecting DNA molecules, very small amounts are unlikely to cause harm as they will be below the threshold to cause damage. There is no known antidote or cure.
Even honey collected from Ragwort has been found to contain small quantities of jacoline, jaconine, jacobine, jacozine, senecionine, and seneciphylline. However these are unlikely to cause harm since the quantities consumed are below the harm threshold.
Medicine
From medieval times to the mid 20th_century, Ragwort was used against inflammations of the eye, for sore and cancerous ulcers, rheumatism, sciatica and gout, for painful joints.
According to some, it would relieve the pain of bee stings.
All applications should be outward only, never internally, and only under professional supervision.
With the large range of pyrrolizidine alkaloids, which are known to inhibit or reduce cell division, some researchers hope to use them to slow down or arrest the growth of cells in cancer.
Other usage
The leaves can be used to obtain good green dye, as yellow dye is obtained from the flowers, as can be done for brown and orange.
Literature
The Greek physician Dioscorides (c.40-90 CE) recommended the herb. The two "fathers" of herbalism, Gerard and Culpeper, also recommended the herb.
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 & litter gold...
- Thy waste of shining blossoms richly shields
- The sun tanned sward in splendid hues that burn
- So bright & glaring that the very light
- Of the rich sunshine doth to paleness turn
- & seems but very shadows in thy sight.
Cultivation
The Ragwort is combatted, not cultivated. There are no varieties known.
Trivia
Ragwort is the national flower of the Isle of Man, where it is known as Cushag.
| Missing image Ragwort.jpg flowering plants | Missing image SenecioJacobea-with-caterpillar.jpg leaves eaten by caterpillar | 
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