Likin’ lichens!

By Dr Poppy Lakeman Fraser
OPAL Coordinator

Likin’ lichens – this is what many a London resident has been doing over the past fortnight.

Together with Pat Wolseley from the Natural History Museum, the OPAL team have been discovering different types of lichens that can be found in and around parks in the capital.

Leafy Xanthoria

The OPAL Air Survey revealed that many of you were recording large numbers of lichens in built-up areas so we thought we would delve deeper into the world of urban lichens and investigate what these curious living patches are on our pavements, benches and trees.

Not sure what a lichen is? Well you wouldn’t be alone. Many people are not aware that lichens are actually two organisms living together. The first partner is a fungus (i.e. is in the same family as the mushroom), and this provides the structure of the lichen.

The second partner is usually an alga (i.e. a plant-like organism that has no roots, stems or leaves) which provides the food for lichen.

Occasionally this second partner could be what’s called a cyanobacteria (blue-green algae) which also produces food from the process of photosynthesis (making food from carbon dioxide and water).

This partnership is called symbiosis because of the close, long-term interaction between the two organisms.

The first port of call for our lichen sessions was Abney Park Cemetery in Stoke Newington. This is a magical park that although very affected by pollutants when London was much more industrial, it is now teeming with lichens. We found over 14 different species of lichen in the hour that we spent nestled up to the gravestones.

Lichenology isn’t for the easily embarrassed; I have to say we did get a few raised eyebrows as our group of 10 lay on the concrete inspecting the so called ‘chewing gum lichen’ (Lecanora muralis).

An OPAL guide to lichensIf you can bear the curiosity of passers-by, then looking at lichens really does provide a glimpse into a whole new world! Their colours, shapes and intricate structures are simply awe-inspiring.

If you fancy finding out more about lichens and how to identify the common ones in your local neighbourhood then our new Urban Lichen Guide will be available soon.

Alternatively, if you live in the London area come along tonight (Tuesday 10 September) to our next FREE session in Hampstead Heath. Please contact opal@imperial.ac.uk to book.

Hope to see you there!

 

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