This is a good time to look at urban lichens, as levels of sulphur dioxide, air pollution and acid rain have been falling rapidly. Many leafy lichens are growing in sites in central London where they may not have been present for 200 years. Illustrated with 49 colour photographs, and including an easy-to-use visual key, this is the second part of the Urban Lichens series. Part 1 (Urban Lichens on Trees and Wood) was published earlier in 2006.