Medieval ‘science’ behind naming of weeds and their dubious medicinal purposes

Long daylight hours, plenty of showers, warm soil, and the weeds in my garden have put on a spurt of growth. I have to mount an offensive, by hand and by hoe, to control them.

Some have started to flower and even produce seeds and this is bad news. There’s an old saying: ‘one year’s seeding, seven years weeding’. Weeding can be satisfying but can also become monotonous. A couple of hours ago boredom set in. I looked at a weed in my hand. It had rather pretty yellow flowers, like tiny dandelion heads the size of a two cent coin. It was very familiar but I realised I didn’t know its name. Plants with yellow flowers resembling dandelions probably make up the most difficult group of Irish wildflowers to identify. There are hawkbits and hawkweeds and catsears and coltsfoots… and this wasn’t any of the above. I decided to take a break from gardening and bring the weed inside to try and identify it online.

I used a website that groups Irish wildflowers by colour. There was a page and a half of thumbnail pictures of yellow flowers and, after a couple of false starts, I clicked on the correct thumbnail and identified my weed — it was nipplewort. An odd name, I thought, so I did a bit more searching.

Nipplewort owes its name to the doctrine of signatures. This was a medical theory developed in Europe in the 16th century. It held that God had put all wild plants on earth for human use and given each plant a signature, or clue, to show people what to use it for. Someone had decided that the unopened flower buds of my weed looked like nipples and therefore God intended it to be used for the treatment of sore or ulcerated nipples. I looked at the flower buds on the weed lying beside my keyboard and decided the whole thing was rather far-fetched.

The doctrine is scientific nonsense. The young leaves of nipplewort, those higher up the stem, are edible cooked and raw but the plant will no nothing for your nipples. However the doctrine has left a considerable legacy in the common English names for plants. The flowers of eyebright, blue surrounded by white, look a little like eyes so the herbalists made eye medicines from it. ‘Wort’ is an old English word for a herb. Hedge woundwort was believed to have antiseptic qualities, liverwort was used to cure liver complaints, and lungwort pulmonary problems. Spleenwort and toothwort are also self-explanatory.

Looking at pictures of these plants gives us an insight into the scientific mind of the late Middle Ages. Science was theocentric but there was a rudimentary knowledge of anatomy. They knew what a lung or a liver looked like and were able to search for plants that resembled these organs. One expert even recommended walnuts for headaches because a walnut looks like a brain.