The little things

It's surprising what can survive in even the bleakest of city streets. While hunting for plants in urban Peterborough, I spotted this colony of common liverwort (Marchantia polymorpha), but on close examination  i found that it was growing alongside a moss (Bryum dichotomum) and three lichens (the greenish-grey Lecanora sp., a yellow Xanthoria sp. and possibly a Physcia sp.). All thriving in a space no bigger than my hand!