Vegetation of stream-bed garigues in the antiapennine range of Tuscany and Latium (central Italy), especially the new association Santolino etruscae-Saturejetum montanae

The authors describe the prevalently chamaephytic vegetation found on terraces of fluvial origin along water courses in the Antiapennine range of Tuscany and Latium (Provinces of Siena, Grosseto and Viterbo) on stable or rarely disturbed sandy-pebbly alluvium. This vegetation is of the primary type, characterized principally by Santolina etrusca, Satureja montana, Teucrium montanum, Helichrysum italicum, Linum tenuifolium and Bromus erectus, strongly determined by soil and closely related to the geomorphological and hydrological features of the station. The syntaxonomic, synecological and syndynamic setting of this vegetation is discussed by comparison with similar types described in other places. A new association, Santolino etruscae-Saturejetum montanae, is proposed. It is temporarily collocated in the alliance Xerobromion (Festuco-Brometea), and has at least two subassociations: the first, saturejetosum, on consolidated material hardly ever subject to disturbance by flooding; the second, inuletosum, on wider, occasionally disturbed terraces. Contact vegetation, linked to the different ecological conditions occurring in these biotopes, is briefly described.