The lichen vegetation of a limestone pavement in the Burren region of western Ireland is described. Species are distributed in relation to gradients of moisture, nutrient-availability and insolation; these in turn may be related to the range of geomorphological micro-features associated with karst. The majority of the 136 stands are dominated by endolithic and foliose cyanophilic lichens. Epilithic, non-cyanophilic crusts grow best on surfaces subjected to occasional bird-manuring. A successional sequence from bare rock through endolithic communities to ones dominated by epilithic, noncyanophilic species does not occur in the Burren.