Reindeer lichen  (Cladonia mediterranea)

Lichens consist of two different organisms, a fungus and either an alga (a simple plant) or a cyanobacterium (bacteria that can photosynthesise), which live together symbiotically, forming a composite organism (3). Many lichens are known to be very sensitive to environmental pollution, and they have been used as 'indicators' species (3). There has been some doubt about the taxonomic status of this species in the UK it was thought that at some sites, the species present may be a form of C. portentosa (1). However, recent genetic analysis by the Natural History Museum on behalf of Plantlife, the wild plant charity, has shown that this species does indeed occur on the Lizard peninsula (5).