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Pastinaca sativa, parsnip

Summary

The upsurge in interest in growing your own food seems to be leading to an increase in problems associated with handling the plant.

Family

Umbelliferae (Apiaceae is the modern name for this family.)

Meaning of the Name

Pastinaca
From the Latin 'pastus' to feed on, especially in the sense of grazing.

sativa
Cultivated 

Common Names and Synonyms

Parsnip, wild parsnip

How Poisonous, How Harmful?

Like the Heracleum mantegazzianum, Pastinaca sativa is known to contain furocoumarins that can make the skin sensitive to light. Little is known, however, about the concentration of these chemicals and whether it varies during the life cycle of the plant.

There are a number of reports in the literature but they tend to indicate only mild to moderate injury.

Many gardeners grow parsnips every year but the number of incidents reported is extremely small. It would require much more research to determine the factors involved in producing harmful events.

Incidents

People who grow parsnips often leave them in the ground and harvest them as required. This may mean that, in the spring, unharvested plants run to seed and are of no use. A visitor to this site reported two occasions when after clearing his allotment of some mature plants on a sunny day, he suffered blistering to his arms and a change in pigmentation which lasted six months. The first year he did not realise what has caused the burns but when it happened a second time he realised that he had been handling the mature Pastinaca sativa previously.

Two children were helping their father remove some run to seed parsnips from the allotment. 48 hours later they came up in blisters described as 'the size of marbles'. It is to be hoped their experience doesn't put them off gardening completely.

Incidents in the literature seem to refer to wild parsnips more often that the cultivated varieties. Some work has suggested that fungal infection of the root results in a significant increase in the furocoumarin content. The work was done using harvested parsnips stored under different conditions but it may explain why the problem occurs only with older plants.

It may be, however, that bright sunlight is required to cause the burning to occur and thus parsnips harvested through the winter do not give rise to problems.

For reasons which are unclear the wild variety of Pastinaca sativa is reported as especially prevalent in Addison County, Vermont, USA and people in the area have been warned to avoid contact with it. It seems, however, that the warning is based on theoretical knowledge rather than any recent incidents.

In August 2010, the UK's Daily Mail reported the case of a woman who removed her shirt on a hot, sunny day whilst working with her parsnips and, having brushed the leaves across her stomach, as she worked, found, two days later that her skin suffered burns and blisters. She was advised to attend hospital.

The woman concerned, Mrs Jo Miles, has been kind enough to give permission for some pictures of the burns she suffered to appear here.

parsnip burns            parsnip burns

parsnip burns parsnip burns

Mrs Miles tells me that she is willing for these pictures to be used because she wants as many people as possible to realise the potential for harm arising from exposing the skin to this plant on a sunny day.

The fact that, it seems, not all parsnip plants produce these effects makes the danger greater because people who have suffered no harm for years may find themselves exposed to a crop which is high in the fourocoumarins that produce the sensitization of the skin.

Folklore and Facts

Pastinaca sativa is an interesting example of the fact that vegetables which people eat without any concern can be harmful in the wrong circumstances. The potential for Solanum tuberosum, potato, to become toxic if exposed to the sun is well-known, as is the poisonous nature of Lycopersicon esculentum, tomato plant, foliage and the need to cook Solanum melongena, aubergine, to destroy the toxins.

Given that some of the possible harm from vegetables is well known, though not the Pastinaca sativa, it seems odd that they are not included in the Horticultural Trades Association classification of potentially harmful plants. The HTA classification rates potentially harmful plants in three classes, though only one plant, which is never sold in the UK, is classified in the highest, 'A', category. Thus X cupressocyparis leylandii, Leyland cypress, are classified as 'C' because contact can result in mild effects but parsnip, which can result in mild to moderate burning, is unclassified and, by implication, harmless. This, on the face of it, looks like another example of the horticultural industry's fear that buyers could be deterred by being given information about a plant's ability to cause problems. 

Though modern carrots are orange, the wild carrot is white and, therefore, there is a lot of overlap between the carrot and the parsnip. John Gerrard comments on this confusion and says that Dioscorides states that deer eat parsnips to protect themselves from serpent bites. Dioscorides' comment, however, appears to have referred to carrot rather than parsnip.

William Rhind states that wild parsnip is sweeter than the cultivated variety and says that, because it needs similar soil to that best suited to potatoes, its cultivation has declined in favour of the more productive potato. He goes on to note that the Irish are said to use parsnip to brew an alcoholic drink.  

The appearance of the parsnip has, unsurprisingly, led to its use as a euphemism for the male organ. There is a saying in France which approximately translates as 'a young man always wants to put his parsnip in an pretty girl's basket'.

In some Celtic cultures, all fires were extinguished on 31st October before being relit from a flame source provided by a priest. The fire was transferred from the priest to the various fires in the home by carrying lighted coals in a hollowed out parsnip or carrot. It is believed that this is the source of the American tradition of hollowing out a pumpkin and placing a lantern in it. The pumpkin was not known in Europe and it is thought that settlers in America found that it provided a better vessel for distributing the Halloween flame than the parsnip.