Caloplaca herbidella. This photograph was taken on an oak tree in Mataelpino in thre Sierra Guadarrama in Spain, which may indicate that the species, in the fertile state is on the northern edge of its range in Britain. Although very rare, this was a species I saw on my very first day studying lichens, when I was shown it by Dr Francis Rose in the New Forest back in 1971!
Species category:
Photo:
![](https://psl.brc.ac.uk/sites/default/files/upload/Caloplaca%20herbidella%203.jpg)