April 30, 2024
Hi, I’m Sim. I am one of the volunteer species champions with the Lost Woods project, helping to develop awareness of different species in woods.
Lichens are the crusty, bushy, or leafy patches of colour you see on growing on the bark of a tree. They’re incredible organisms, especially if you magnify them, and vary hugely. My interest was piqued when I saw a Golden Eye lichen on a Hawthorn on Malling Down. I was fascinated by its form!
I am not an expert in lichens, but I am an enthusiast. I am a member of the British Lichen Society and I regularly go on field trips with lichenologists. You certainly don’t need to be an expert to enjoy lichens though. Here are some top tips on what to look for- I promise you'll never look at lichens the same way again.
The above lichen’s structures, its circular fruits (apothecia) and it’s eye-lashed (fibrils) are visible to the naked eye; but many lichens on trees are small and require magnification to see.
To get a good view of a lichen you may want to get a hand lens (aka a Jewellers’ Loupe); you can get a good hand lens for £10-£20.
This Rosette Lichen for example is tiny!:
But below is what a Fringed Rosette lichen looks like when magnified.
Now you can see its “fringes” (marginal cilia) and its amazing colours and forms. Rosette lichens are very common and you can probably see them on almost any Hawthorns in the Lost Woods, and on most Oaks, Ashes and Sycamores.
Lichens are one of the ‘epiphytes’ that grow on trees, along with mosses and liverworts. An epiphyte is any organism that grows upon a plant merely for physical support; they are not parasitic. In some places, like Lag Wood in Hassocks, there are also epiphytic Polypody ferns growing high up in the canopy of ancient Oaks. Lichens also grow on rocks, gravestones, the soil, metal, and plastic (for example on the bins of Brighton!).
So, if lichen are not taking anything from trees, where do lichens get their food?
They get it from their mates – algae or cyanobacteria! Lichens are not one organism but at least two – a fungi (not the type that eats trees) – and at least one alga or cyanobacteria, that photosynthesise energy from light for the fungi. They live together permanently in “mutualistic symbiosis”. The fungi of the lichen provides a home for the algae/cyanobacteria in habitats that wouldn’t normally suit them.
If you want to start engaging in the fascinating world of lichen, you might want to get an ID chart. For £4 you can but a Lichens on Twigs photo chart from the Field Studies Council; it will keep you going for ages!
Or you could attend a Lost Wood introduction to lichen session. Later in the year, Lost Woods wildlife champions will be offering guided woodland walks for community and conservation groups.
If your group is based in the Lost Woods project area and would like to request a lichen walk, please email Michael at lostwoodsteam@ruralsussex.org.uk.