Look out for lichen

WHILE FOLIAGE AND FLOWERS ARE SCARCE DURING THE COLDEST MONTHS, stalwart-natured lichens continue to thrive. An intriguing combination of fungus and algae, there are around 1,700 species in the British Isles, and, with their crackled, leaf-like growth, they add texture and interest to everything from bark, leaves and exposed soil to dry-stone walls, roofs and gravestones. Thought to be among the oldest organisms on earth, lichen can be used to determine the age of exposed rock (known as lichenometry). On winter walks, look out for the sinuous, pale-green oakmoss, whose flattened lobes resemble miniature antlers, and the leafier grey-blue shield variety. For more details, see woodlandtrust.org.uk.