This is a local community, found mainly on
Carboniferous limestone in England and Wales. It is an early coloniser of limestone
screes and slopes, but is only able to persist if the talus if especially coarse or if there is limited grazing, both conditions which inhibit invasion by scrub and woodland species. This community was first described in Britain by Shimwell, who assigned it to the
Gymnocarpietum robertianae (Kuhn 1937), previously described from Germany. ==References==