It is one of six communities of crevice, scree and spoil vegetation.
[1] This community is widely distributed in areas of suitable habitat, especially in the west of Britain.
Four constant species are found in this community: Two rare species are associated with the community: This community require a lime-rich substrate and its natural habitat is crevices in limestone bedrock, especially in western Britain, where the more humid conditions are favourable to the weathering of suitable rocks.
The Sedum acre - Arenaria serpyllifolia subcommunity typically contains many more vascular plants, with sheep's fescue (Festuca ovina), wild thyme (Thymus praecox) and biting stonecrop (Sedum acre) the most frequent.
Maritime communities and vegetation of open habitats.