The flora and vegetation of this well-defined physiognomic unit in eastern England show relationships with continental Europe as well as with the oceanic West. Preliminary to more detailed analysis, a general account of the relationships between climate, soil and vegetation is given. The climate combines certain continental and oceanic features. The continental feature of dryness (low rainfall with a tendency towards a maximum fall in summer) is accentuated by the highly permeable soil. The soils are genetically related; in the main they are derived from chalky boulder clay (approx. 50% chalk and 50% sand) and show a complete developmental series from slightly leached chalky boulder clay, through soils with little CaCO3 to well developed pod-sols: further variation is caused by widespread erosion, truncation and burial of the soil in place. The 4 major plant communities, fescue-bent, sand-sedge, heather, and bracken, show considerable variation closely linked with the development of the soil profile. Thus the fescue-bent varies markedly in floristic composition, including communities closely related to the floristically rich chalk grassland as well as impoverished types excluding all but the most tolerant spp. Single dominants express the variation chiefly in their varying height and density.