Ancient town walls and similar structures which are not derelict. Frequently with pteridophytes. Other possible species include: Parietaria judaica, Mercurialis annua, Hyoscyamus albus, Verbascum undulatum, Capparis spinosa ssp. spinosa, Micromeria juliana, Diplotaxis tenuifolia, Sedum album, Lactuca serriola, Asphodelus fistulosus, Bromus madritensis, Erysimum cheiri, Antirrhinum majus, Sonchus oleraceus.