‘In all things of nature there is something of the marvellous.’ ~ Aristotle
‘The beauty of the natural world lies in the details.’ ~ Natalie Angier
‘A multitude of small delights constitutes happiness.’ ~ Charles Baudelaire
From my reading I’ve discovered that these cup lichen – Cladonia, by name – are what reindeer and caribou like to eat most. Well, I did see a jolly looking man wearing a bright red jacket walk past just before I took these photos, but I doubt there’s enough Cladonia in my local park to keep Santa’s sleigh-pullers going for more than a kilometre of their round-the-world trip in December, so I don’t think he was Father Christmas looking for potential refuelling stops!
I don’t know exactly which species of Cladonia I’ve found (and I haven’t yet waded through the 42-page key I downloaded!) and it seems you need a certain level of scientific vocabulary to determine this anyway (the first 5 pages of the key are devoted to a glossary of terms!) but I love the common names many of them have: Pixie cup lichen and Red-fruited pixie cup, Lipstick powderhorn, Trumpet lichen and Felt horn lichen, Dragon lichen, Wand lichen and British soldiers. The references to the colour red and to lipstick are due to the red-coloured fruit that appear on top of their goblet-shaped stalks (podetia). Unfortunately, there is only the merest hint of red in the photo above but, if I do manage to see them in full fruiting display, I’ll post another blog to show you.
If you go for a wander through your local cemetery, this is one of the most common lichen you will see on old limestone headstones and grave monuments. Growing up to 10cm (4 inches) across and coming in vibrant shades of yellow and orange, the crust lichen Caloplaca flavescens is easy to spot.
The outer part of the thallus (that’s lichen for body!) has lobes and, at least in the beginning, the pattern in its centre can look a little like white dried-out mud (or, as one website described it, ‘crazy paving’) but that part later seems to disappear, leaving a single outer ring, or a series of thin arcs, that look to me almost like the outline of a rose in flower. If you look very closely, you can sometimes see the fruiting bodies (known as apothecia). These are a darker orange, disc-shaped, and tiny (up to 1.5mm across) – you might need your specs to see them.
Of course, you don’t just see this lichen in graveyards. It can be found on any calcareous rocks and walls, particularly those where birds have frequently been perching, as this lichen finds nourishment in nutrient-rich bird poo!
One way to get kids interested in lichen is to ask them to find the secret writing on woodland trees. The ‘writing’ is made by a lichen, Graphis scripta, which forms long narrow wiggledy black fruiting bodies (apothecia) on its pale smooth crust.
Not surprisingly, this lichen’s common names include script lichen, secret writing lichen, pencil-mark lichen, or hieroglyphics lichen. It is very common on smooth-barked deciduous trees, their twigs and branches, and can be found around the world – does the writing change its language depending on location, I wonder?
Lichens are very sensitive to air quality and, as they are able to accumulate and retain heavy metals, they are often used as a tool to monitor heavy metal pollutants in the atmosphere. Graphis scripta has been utilised in this way by scientists studying air pollution in the Indian city of Bangalore.
What substance produces a beautiful lilac dye and is one of the raw materials in many well-known perfumes? It’s called Oakmoss (Evernia prunastri), but it’s not a moss, it’s a lichen, and it doesn’t just grow on oak trees, it grows on the bark of other deciduous trees and conifers as well, in most of the temperate regions of the northern hemisphere. Another of its common names is Staghorn lichen because its branching shape resembles the antlers of deer.
At one time, Oakmoss was one of the most common base materials used in the Chypre and Fougère categories of perfumes, and was highly valued for the rich, earthy and, apparently, very sensual aroma it added to these fragrances. Unfortunately, Oakmoss can produce severe reactions in people with sensitive skin, so the IFRA (the International Fragrance Association) has now imposed restrictions on its use though, through the prudent manipulation of their recipes, it seems Oakmoss is still to be found in many well-known perfumes, like Paloma Picasso, Chanel No. 19 and Miss Dior.
And, if you’re keen to use natural products to dye wool or fabric products, soaking this lichen in a mixture of water and ammonia will produce a vibrant lilac-coloured dye.
Though lichens are generally intolerant of pollution, this vibrant yellow and orange beauty is an exception and is even tolerant of heavy metal contamination. Its common names include common orange lichen, yellow scale, maritime sunburst lichen and shore lichen, from which you might correctly deduce that Xanthoria parietina is just as common on a rock at the seaside as it is on a tree in the city. It is also something of a globetrotter, being found throughout Britain and most of Europe, in North America, Africa and Asia, as well as in Australia.
Working from the belief that a plant could treat a disease it most looked like, medieval herbalists used Xanthoria parietina to treat jaundice because of its yellow colour, and scientific research has since shown that it has potent antiviral properties. And, given the intense yellow and orange colours of this lichen, it’s probably no surprise to learn that it has also been used as a dye. It is, for example, one of the traditional plant materials used to dye wool in the Scottish highlands and islands, though the colour it produces is brown, not yellow.
I keep thinking I see letters of the alphabet in these photographs as if this lichen is trying to tell me something but I can’t quite make out the message!
Though I’m finding lichens quite difficult to identify, even with my newly acquired guide charts, I’m fairly sure this is Lecanora chlarotera, a very common and widespread British lichen. As it will tolerate moderate amounts of air pollution, it can frequently be seen on the twigs and trunks of young semi-urban tree plantings, of the sort you might see around a shopping centre. It is also found in sparsely planted woodlands, where it benefits from more light than a densely planted forest would provide.
The lichen’s base colour ranges from cream to pale grey, it varies in texture from smooth to what one website describes as ‘strongly warted … like lumpy porridge’, and its apothecia (the little saucer-shaped fruiting bodies) range in colour from pale beige to a rusty brown. As with most lichens, you have to look closely to see how pretty it is.
Lichen have two methods of reproduction: one is asexual – they simply expand to cover more of the surface on which they’re living; the other is sexual but, it’s not the actual lichen that is reproducing sexually, it’s the fungus the lichen is in a symbiotic relationship with.
The saucer-shaped discs in my photos are apothecia, one of the two main types of sexual fruiting bodies of the fungi in the Ascomycota group, to which the majority of lichens belong. Spores (the correct term is propagules) are dispersed from these discs by air, water or attaching themselves to minibeasties, and must then meet up with an algal partner in order to form new lichen.
The yellow- and orange-coloured lichen in these photographs are, I believe, Xanthoria parietina, which is very common on both tree bark and stonework throughout Britain, and has a particular liking for Elder trees and coastal rocks.
Bordering the recreation grounds opposite where I live is a magnificent long line of copper beech trees. Their leaves provide a glorious show of colour in spring, summer and autumn but the trees look rather barren during the winter months. However, if you look closer, you’ll find their bark is alive with algae, mosses and lichens, and the colours, shapes and patterns of these small organisms are, indeed, many and splendid.
A lichen is a complicated entity – it is not actually one single organism but rather a fungus living in a symbiotic relationship with a photosynthetic partner, which might be a green alga or a cyanobacterium or both. The fungus is the farmer and the alga and/or bacterium produce/s the food it survives on.
Next time you see a lichen, look closer and be amazed!