Another wilding, growing by a doorway in rue Réamur.   Native to rocky places in southern Europe, with a preference for limestone, Cymbalaria muralis is now naturalised in most parts of Europe. It needs cracks and crevices to get a toe hold in a wall so ruins are an ideal habitat, but any stone or brick will do if there’s crumbling mortar to supply a touch of lime.

Known in Britain as ivy-leaved toadflax, the French name, Ruine de Rome, is rather more poetic.  There’s nothing in the plant’s behaviour to suggest it could have contributed to Rome’s downfall, though it is long established on walls in that city.   One theory is that the plant was imported to France from Italy in the 18th century, to decorate the walls of artificial ruins in the newly fashionable landscape gardens.  The plant’s name added a touch of ancient history, essential for the success of a good ruin.