Would you mistake the highly poisonous woodland plant, Dog’s Mercury (Mercurialis perennis) for the edible, semi-aquatic Brooklime (Veronica beccabunga)?

Brooklime and Dog's Mercury

In 1982, a 40 year old schoolmaster and his 39 year old wife did, with near-fatal consequences. They based their identification on a small black-and-white line illustration in the 1975 edition of Richard Mabey’s  Food for Free.

In fairness to the book, the image, which in my opinion looks like Brooklime as intended, and not like Dog’s Mercury, was clearly never meant to be used for ID. There is no additional description or further detail. So why stake your life on it?

Well, enthusiasm sometimes gets the better of us. Every now and then the impatient desire to forage a free meal overrides a person’s knowledge or experience or powers of observation; the notion of a patient apprenticeship is exchanged for a steep learning curve.

Acquiring identification skills takes time and practise. If all you want to do is give something its correct name, there is no harm done if you later find out you were wrong. We all have to learn. When studying, a sound approach is to give your specimen (or perhaps a digital photo) a provisional identification that may one day be confirmed. Read the additional information in the text, and use all your senses. ID first then, perhaps eat it the following year after you have seen the plant in all stages and looked at it carefully. Training your eyes and brain to recognise subtle differences between things take time, and the keener we are sometimes the less we look. In fact, we carry preconceptions in our heads that can stop us seeing what is truly there.

Ray egg-case or bat?

This was brought home to me very strikingly recently. I had a display of Natural History items at a country event. Amongst them were several black ‘mermaid’s purses’, the egg cases of skates/rays that get washed up on the beach. Several times that day different people said to me ‘Those are bats’. Something black with vaguely hook-shaped appendages, no eyes, mouth, ears or any features at all, had defaulted to ‘bat’ in their minds and they looked no further until I pointed out their mistake.

We are probably all guilty of doing it to a greater or lesser extent but we should take special care whilst foraging. Dog’s Mercury has also been taken for Spearmint (Mentha spicata) (despite not smelling minty) and Fat Hen (Chenopodium album), amongst others. Compare the Brooklime and Dog’s Mercury in the photos. I hope they are helpful, but don’t base your breakfast on them.