A weed with great wee qualities

COWSLIPs and violets are having a bumper year.

Everyone is delighted.

Dandelions are also thriving but, with them, it’s a different story.

Roadside verges, fields and unmowed lawns are ablaze with their bright yellow flowers, but few people welcome this humble weed.

It’s even got a put-down nickname; ‘piss-a-bed’ is a translation from the French ‘piss en lit’. Drinking the milky juices of dandelion stems induces urination and doing so, folk medicine practitioners claim, removes toxins from the body. Herbalists prescribe the plant for liver and kidney disorders. The supposed health effects may be an old wife’s tale but the plant has culinary virtues. Although contact with the leaves sometimes causes allergies, they are eaten in salads. Dandelion wine can be quite potent. ‘Dent de lion’ or ‘dens leonis’ means ‘lion’s tooth’. Perhaps the long serrated leaves, or the huge tap-root, call to mind a big cat’s formidable teeth.

This cold-tolerant species is one of our oldest Irish weeds. According to Jonathan Pilcher and Valerie Hall in Flora Hibernica, the dandelion may even have survived the last ice age, isolated in pockets of exposed soil. At any rate, when the glaciers retreated all those millennia ago, great expanses of rough disturbed soil were exposed. Conditions during the long wet summer days were ideal for dandelions. The current economic recession offers a faint reminder of those ancient times; Ireland, just now, is dotted with the shells of half-built houses and commercial buildings, surrounded by rough ground disturbed by mechanical diggers and bulldozers. Hardy opportunist weeds love abandoned building-sites.

The dandelion is very much a loner; it wants the place all to itself. Encroaching neighbours, such as nettles and thistles, shade the light from its flat ground-hugging leaves. When other weeds come too close, the dandelion, starved of light, must leave. It has little problem doing so; mobility is one of its great skills.

Just now the bright flower-heads, each an assembly of tiny florets, are fading fast, transforming themselves into grey ‘monk’s heads’ or ‘priest’s crowns’. A dandelion ‘clock’ has hundreds of seeds. As children used to think, you can tell the time by blowing on them and counting the number left behind. Each seed is equipped with its own little parachute and the seed-head is pushed aloft on a long stalk where the breeze can grab it. Some stalks are almost half a metre long. Once airborne in a stiff breeze, the little sky-divers may travel for miles; the dandelion Diaspora is always expanding.

This trespassers-will-be-prosecuted weed, not only resents the presence of other plants, it has little time even for its own kind. The yellow flowers produce pollen to attract bees. The heads are equipped with male organs but fertilisation seldom takes place. Celibacy is the norm for this anti-social hermit. No sex please we’re dandelions! The parachuting babies are clones, exact genetic copies of their mother. Parthenogenesis, virgin birth, is a risky venture.

Virgin offspring resemble Model-T cars coming off a production line; when a genetic copying error occurs somewhere along the line, all the seeds produced from then on carry the defect.

Sex may be messy but it provides a more secure future; the deck of genetic cards is constantly shuffled. Teaming up with partners provides a more diverse progeny and greater capacity to adapt to life’s ups and downs. So, once in a blue moon, dandelions begrudgingly allow fertilisation to take place; as St Paul said ‘ it is better to marry than to burn’! Breeding without a father is a legacy of the weed’s pioneering lifestyle; potential partners will be thin on the ground when you parachute into a remote area. With their genetic isolation, many dandelion lines are on the way to becoming distinct species.

But are there more dandelions around this year? According to Dr Matthew Jebb of the National Botanic Gardens, the current explosion is to some extent a case of increased visibility.

Spring has been late, the soil is still cold and the growth of grasses delayed. The absence of grass renders dandelions, cowslips and violets more visible than normal. But the short grass and lack of competition give dandelions the isolation they crave. This year, they are at their best.

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Saturday, January 23, 2021

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