One exception, however, is navelwort (Umbilius rupestris) which gets its name from the way the stalk joins the leaf in the middle, marked by a dimple on the top. Alternatively, however, it is often known as pennywort, thanks to its circular shape, roughly the size of a coin.

At first glance this is an extremely unlikely winter food. To start with, it is basically a desert plant, equipped with thick waxy leaves to withstand heat and drought – so why is it abundant in winter – and particularly so in Europe’s dampest regions?

The answer is that it grows in the arid conditions of rocky crevices and drystone walls. In former times it was far more widespread, – in the 16th century John Gerrard found it on the wall of Westminster Abbey – but today it is largely confined to the West Country and Wales.

Thanks to the rich moist texture of its leaves, it was once used as a poultice for burns, but modern fabrics and antiseptics do a far better job today. Much more preferable, however, is to eat it. The succulent leaves taste delicious, with a flavour reminiscent of lambs lettuce. Pennywort is slow-growing, however, so only harvest selectively from areas where it is locally abundant and be selective, leaving plenty to regenerate.

This article is reproduced by kind permission of Daniel Butler www.fungiforays.co.uk