Lichens 2016

This year the first expert identification of lichens was carried out.

Ishpi Blatchley, our expert, made an initial survey and then took a small group round to show us what she had found in her 2 hours in the cemetery. We learnt that each lichen is really 2 organisms not one – a fungus (which has shape and form – usually producing spores) living with and providing physical protection for one or more algae which carry out photosynthesis and produce food for both.

Ishpi took us to a humble looking tree that had 15 different species of lichen on its bark with branches conveniently at the right height for inspection!

The majority of lichens were no more than a few centimetres in diameter and in a wonderful range of colours – almost luminous green to soft sea-green to bright yellow ochre. Their world really came alive on using a lens – fruiting bodies (fruits) in different shapes and colours, some resembling little jam tarts.

We learnt about the three main groups of lichen: crustose, foliose and fruticose. The crustose (crusty) ones were very much ‘stuck’ to the bark and no amount of scraping with a fingernail could dislodge them. In contrast the foliose (‘leafy’) ones had delicate little lobes that could be dislodged. The fruticose (bushy) lichens were very much 3D – quite bushy and much less common in the cemetery.

Identification relies on putting them into their 3 main groups – looking at their growth form, their fruiting bodies, and colour. Where they choose to grow if on grave stones is also relevant– some preferring acid stones (e.g. granite or sandstone) and some more basic stone (ie limestone). Ishpi did some simple tests in the field but others needed to be identified under a microscope.

Some of those we were shown included: Psilolechia lucida, Lecanora muralis, Lecanora campestris, Lecanora chlarotera, Lecidella elaeochroma, Xanthoria parietina, Xanthoria calcicola, Parmelia sulcata.