Lichenicolous Fungi

 

Lichenicolous fungi are fungi that live on lichens. The word simply means “lichen-dwelling”, but the reality is far more fascinating. These species use lichens as their habitat, and often as their food source too. Some are parasitic, visibly damaging their host. Others appear to be more benign, living alongside the lichen with little obvious harm. Either way, they represent an entire hidden layer of biodiversity that most people never notice.

​

To understand them, it helps to remember that a lichen is itself a partnership between a fungus and an alga (and/or cyanobacterium). A lichenicolous fungus is therefore a fungus living on another fungus-alga partnership — an ecological relationship stacked on top of another. In some cases, these fungi form tiny black pimples, colourful cushions or powdery patches erupting from the surface of a lichen thallus. In others, the only clue is distortion of the host’s form or a subtle change in colour.

​

North Wales is exceptionally rich in lichens, from ancient woodland specialists to upland rock species and maritime communities along the coast. Where lichens thrive, lichenicolous fungi follow. Many are highly host-specific, meaning they will only grow on one particular lichen species. This makes them both challenging and rewarding to record. Finding one often requires careful hand-lens work and a good knowledge of the host lichen in the first place.

​

These fungi are important indicators of healthy, long-established lichen communities. Because they depend entirely on their hosts, they cannot exist where lichens are absent or degraded. Recording them adds depth to our understanding of habitats and reveals just how intricate ecological networks can be, even on the surface of a single rock or tree trunk.

​

Lichenicolous fungi are small, overlooked and often technically challenging to identify — but that is part of their appeal. They reward patience, close observation and curiosity, turning an already rich lichen flora into an even more complex and beautiful world waiting to be discovered.