Study area - The Flemish district
The Flemish district (Fl.) is also a fairly flat region; it corresponds to the plains of Quaternary sand deposited over sand and clays of the Eocene or of more recent origin. It is strongly urbanized and industrialized, even in terms of agricultural practices. Almost all ericaceous heaths have indeed disappeared. There is no natural rock outcrop, and woodland areas are now very reduced and strongly altered. The lichen flora is confined to isolated trees, old walls, especially on churches and in cemeteries, but has lost any outstanding feature; atlantic species characteristic of old forests found in the district until the end of last century have now all disappeared.