While preparing for my lichen ‘walk’ on campus I examined one of the Horse chestnut trees near the pond in the Harris Garden. I’ve used this tree for teaching lichens on the MSc Plant Diversity course for the last three years. This time I spotted something new.
Normandina pulchella is an interesting lichen that grows as oyster-shell shaped squamules (small thalli of limited size). It has raised margins that develop a coating of small flour-like soredia. These are small bundles of fungal hyphae and algal cells that can break off and grow into a new thallus elsewhere – a form of asexual reproduction.
Normandina is expanding it’s range throughout the south of Britain, probably in response to less sulphur dioxide pollution. This is the first time that the species has been recorded in Berkshire.